intersil HSP50214B DATA SHEET

®
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HSP50214B
Data Sheet May 1, 2007 FN4450.4
Programmable Downconverter
The HSP50214B Programmable Downconverter converts digitized IF data into filtered baseband data which can be processed by a standard DSP microprocessor. The Programmable Downconverter (PDC) performs down conversion, decimation, narrowband low pass filtering, gain scaling, resampling, and Cartesian to Polar coordinate conversion.
The 14-bit sampled IF input is down converted to baseband by digi
tal mixers and a quadrature NCO, as shown in the Block Diagram. A decimating (4 to 32) fifth order Cascaded Integrator-Comb (CIC) filter can be applied to the data before it is processed by up to 5 decimate-by-2 halfband filters. The halfband filters are followed by a 255-tap programmable FIR filter. The output data from the programmable FIR filter is scaled by a digital AGC before being re-sampled in a polyphase FIR filter. The output section can provide seven types of data: Cartesian (I, Q), polar (R, θ), filtered frequency (dθ/dt), Timing Error (TE), and AGC level in either parallel or serial format.
Features
• Up to 65MSPS Front-End Processing Rates (CLKIN) and 55MHz Back-End Processing Rates (PROCCLK) Clocks May Be Asynchronous
• Processing Capable of >100dB SFDR
• Up to 255-Tap Programmable FIR
• Overall Decimation Factor Ranging from 4 to 16384
• Output Samples Rates to ≅ 12.94MSPS with Output Band
widths to ≅ 982kHz Lowpass
• 32-Bit Programmable NCO for Channel Selection and Carrier Tracking
• Digital Resampling Filter for Symbol Tracking Loops and Incommensurate Sample-to-Output Clock Ratios
• Digital AGC with Programmable Limits and Slew Rate to Opt
imize Output Signal Resolution; Fixed or Auto Gain
Adjust
• Serial, Parallel, and FIFO 16-Bit Output Modes
• Cartesian to Polar Converter and Frequency Discriminator for AFC Loops and Demodulation of AM, FM, FSK, and DPSK
• Input Level Detector for External I.F. AGC Support
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• Single Channel Digital Software Radio Receivers
• Base Station Rx’s: AMPS, NA TDMA, GSM, and CDMA
• Compatible with HSP50210 Digital Costas Loop for PSK Rece
ption
• Evaluation Platform Available
Ordering Information
PART NUMBER PART MARKING TEMP. RANGE (°C) PACKAGE PKG. DWG. NO.
HSP50214BVC HSP50214BVC 0 to +70 120 Ld MQFP Q120.28x28 HSP50214BVCZ (Note) HSP50214BVCZ 0 to +70 120 Ld MQFP (Pb-free) Q120.28x28 HSP50214BVI HSP50214BVI -40 to +85 120 Ld MQFP Q120.28x28 HSP50214BVIZ (Note) HSP50214BVIZ -40 to +85 120 Ld MQFP (Pb-free) Q120.28x28
NOTE: Intersil Pb-free plus anneal products employ special Pb­termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
free material sets; molding compounds/die attach materials and 100% matte tin plate
1
Block Diagram
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MICROPROCESSOR
C(7:0)
IN(13:0)
GAIN
ADJ
(2:0)
COF SOF
CLKIN
PROCCLK
REFCLK
READ/WRITE
LEVEL DETECT
INPUT
SECTION
CARRIER
NCO
CONTROL
TH
5
ORDER
CIC
FILTER
TH
5
ORDER
CIC
FILTER
FILTERS
HALFBAND
FILTERS
HALFBAND
HSP50214B
255-TAP
FIR FILTER
255-TAP
FIR FILTER
RESAMPLING
NCO
AGC LOOP FILTER
POLYPHASE
FIR AND
HALFBAND
FILTERS
POLYPHASE
FIR AND
HALFBAND
FILTERS
Δ
I OUT
CARTESIAN
TO
POLAR
COORDINATE
CONVERTER
Q OUT
DISCRIMINATOR
TIMING ERROR
AGC
MAG.
PHASE
FREQ
SEROUTA
SEROUTB
AOUT(15:0)
BOUT(15:0)
OUTPUT FORMATTER
2
FN4450.4
May 1, 2007
Pinout
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HSP50214B
HSP50214B
(120 LD MQFP)
TOP VIEW
OEAL
GND
AOUT0
AOUT1
AOUT2
AOUT3
AOUT4
NC
VCCAOUT5
AOUT6
AOUT7
AOUT8
AOUT9
NC
GND
AOUT10
AOUT11
IN11
IN13
IN12
GND
REFCLK
VCCAGCGNSEL
OEAH
AOUT13
AOUT14
AOUT15
AOUT12
IN10
IN9 IN8
GND
IN7
NC IN6 IN5 IN4 IN3 IN2
GND
IN1 IN0
V
CC
CLKIN
GND
NC
ENI GAINADJ2 GAINADJ1 GAINADJ0
COF
COFSYNC
GND
SOF
SOFSYNC
V
CC
SYNCIN1 SYNCIN2
103
102
101
100
117
118
119
120 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
32
31
115
116
333435363738394041424344454647484950515253545556575859
111
112
113
114
105
104
106
107
108
109
110
95
96
97
98
99
91
92
93
94
90
DATARDY OEBH
89
BOUT15
88
BOUT14
87
V
86
CC
NC
85
BOUT13
84
BOUT12
83
BOUT11
82
BOUT10
81
BOUT9
80
BOUT8
79
GND
78
GND
77
PROCCLK
76
V
75
CC
MSYNCI
74
MSYNCO
73 72
GND
71
BOUT7
70
BOUT6 BOUT5
69
GND
68
BOUT4
67
NC
66
BOUT3
65
BOUT2
64
BOUT1
63
BOUT0
62
OEBL
61
60
3
SYNCOUT
WR
INTRRP
RD
GND
C7
C6NCC5
C3C2C1NCC0A2A1
C4
CC
V
A0
GND
SEL2
SEL1
GND
SEL0
CC
V
SEROE
SEROUTB
SERSYNC
SERCLK
FN4450.4
May 1, 2007
SEROUTA
HSP50214B
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Pin Descriptions
NAME TYPE DESCRIPTION
V
CC
GND - Ground.
CLKIN I Input Clock. This clock should be a multiple of the input sample r
IN(13:0) I Input Data. The format of the input data may be set to offset binary or 2’s complement. IN13 is the MSB (see Control
ENI I Input Enable. Active Low. This pin enables the input to the part in one of two modes, gated or interpolated (see
GAINADJ(2:0) I GAINADJ Input. Adds an offset to the gain via the shifter following the mixer. GAINADJ value is added to the shift
PROCCLK I Processing Clock. PROCCLK is the clock for all processing functions fo
AGCGNSEL I AGC Gain Select. This pin selects between two AGC loop gain
COF I Carrier Offset Frequency Input. This serial inpu
COFSYNC I Carrier Offset Frequency Sync. This signal is asserted one CLK befor
SOF I Re-Sampler Offset Frequency Input. This se
SOFSYNC I Re-Sampler Offset Frequency Sync. This signal is asserted
AOUT(15:0) O Parallel Output Bus A. Two parallel output modes are available on th
BOUT(15:0) O Parallel Output Bus B. Two parallel output modes are available on th
- Positive Power Supply Voltage.
ate. All input section processing occurs on the rising
edge of CLKIN. The frequency of CLKIN is designated f
rd 0).
Wo
Control Word 0). In gated mode, one sample is taken per CLKIN when designated f
co
de from the microprocessor (μP) interface. The shift code is saturated to a maximum code of F . The gain is of fset by (6dB)(GAINADJ); (000 = 0dB gain adjust; 111 = 42dB gain adjust) GAINADJ2 is the MSB. See “Using the Input Gain Adjust Control Signals” Section.
performed on PROCCLK’s rising edge. All output timing is derived from this clock. This clock may be asynchronous to CLKIN.
Gain setting 1 is selected when AGCGNSEL = 1.
(see Serial Interface Section). The offset may be 8, 16, 24, or 32-bit s. The setup and hold times are relative to CLKIN. This input is compatible with the outp ut o f t he HSP5 0210 Costas loop [1].
frequency word (see Serial Interface Section). The setup and hold times are relative to CLKIN. This input is compatible with the output of the HSP50210 Costas loop [1].
NCO (see Serial Interface Section). The offset may be 8, 16, 24, or 32-bits. The setup and hold times are relative to PROCCLK. This input is compatible with the output of the HSP50210 Costas loop [1].
(see Serial Interface Section). The setup and hold times are relative to PROCCLK. This input is compatible with the output of the HSP50210 Costas loop [1].
Output Port, where the source is selected through Control Word 20 (see the Microprocessor Write Section) and comes directly from the Output MUX Section (see Output Control Section). The most significant byte of AOUT always outputs the most significant byte of the Parallel Direct Output Port whose data type is selected via μP interface. AOUT15 is the MSB. In this mode, the AOUT(15:0) bus is updated as soon as data is available. is asserted to indicate new data. For this mode, the output choices are: I, |r|, or f. The format is 2’s complement, except for magnitude, which is unsigned binary with a zero as the MSB. The second mode for parallel data is called the Buffer RAM Output Port. The Buffer RAM Output Port acts like a
O for blocks of information called data sets. Within a data set is I, Q, magnitude, phase, and frequency
FIF information; a data type is selected using SEL(2:0). Up to 7 data sets are stored in the Buffer RAM Output Port. The LSBytes of the AOUT and BOUT busses form the 16-bits for the buffered output mode and can be used for buffered mode while the MSBytes are outputting data in the direct output mode. For this mode, the output formats are the same as the Direct Output Port mode.
Output Port, where the source is selected through Control Word 20 (see the Microprocessor Write Section) and comes directly from the Output MUX Section (see Output Control Section). The most significant byte of BOUT always outputs the most significant byte of the Parallel Direct Output Port whose data type is selected via μP interface. BOUT15 is the MSB. In this mode, the BOUT(15:0) bus is updated as soon as data is available. is asserted to indicate new data. For this mode, the output choices are: Q, φ, or |r|. The format is 2’s complement, except for magnitude which is unsigned binary with a zero as the MSB. The second mode for parallel data is called the Buffer RAM Output Port. The Buffer RAM Output Port acts like a
O for blocks of information called data sets. Within a data set is I, Q, magnitude, phase, and frequency
FIF information; a particular information is selected using SEL(2:0). Up to 7 data sets is stored in the Buffer RAM Output Port. The least significant byte of BOUT can be used to either output the least significant byte of the B Parallel Direct Output Port or the least significant byte of the Buffer RAM Output Port. See Output Section. For this mode the output formats are the same as the Direct Output Port mode.
, which can be different from f
S
when ENI is used.
CLKIN
t pin is used to load the carrier of fset f reque ncy in to t he C arrie r NCO
rial input pin is used to load the offset frequency into the Re-Sampler
.
CLKIN
ENI is asserted. The input sample rate is
llowing the CIC Section. Processing is
s. This input is setup and held relative to PROCCLK.
e the most significant bit (MSB) of the offset
one CLK before the MSB of the offset frequency word
e HSP50214B. The first is called the Direct
e HSP50214B. The first is called the Direct
DATARDY
DATARDY
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HSP50214B
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Pin Descriptions (Continued)
NAME TYPE DESCRIPTION
DATARDY O Output Strobe Signal. Active Low. Indicates when new data from the Direct Output Port Section is available.
OEAH I Output enable for the MSByte of the AOUT bus. Active Low. The AOUT MSByte outputs are three-stated when
OEAL I Output enable for the LSByte of the AOUT bus. Active Low. The AOUT LSByte outputs are three-stated when
OEBH I Output enable for the MSByte of the BOUT bus. Active Low. The BOUT MSByte outputs are three-stated when
OEBL I Output enable for the LSByte of the BOUT bus. Active Low. The BOUT LSByte outputs are three-stated when
SEL(2:0) I Select Address is used to choose which information in a data set fr
INTRRP O Interrupt Output. Active Low. This output is asserted for 8 PROCCLK cycles when the Buffer RAM Output Port is
SEROUTA O Serial Output Bus A Data. I, Q, magnitude, phase, frequ
SEROUTB O Serial Output Bus B Data. Contents may be related to SEROUTA. I, Q, magnitude, phase, frequency, timing error
SERCLK O Output Clock for Serial Data Out. Derived from PROCCLK as give
SERSYNC O Serial Output Sync Signal. Serves as serial da
SEROE I Serial Output Enable. When high, the SEROUTA, SEROUTB, SERCLK, and SERSYNC signals are set to a high
C(7:0) I/O Processor Interface Data Bus. See Microprocessor Write Section. C7 is the MSB.
A(2:0) I Processor Interface Address Bus. See Microprocessor
WR I Processor Interface Write Strobe. C(7:0) is written to Control Words selected by A(2:0) in the Programmable Down
RD I Processor Interface Read Strobe. C(7:0) is read from output or status locations selected by A(2:0) in the
REFCLK I Reference Clock. Used as an input clock for the timing error de
MSYNCO O Multiple Chip Sync Output. Provided for synchronizing multiple parts when CLKIN and PROCCLK are
MSYNCI I Multiple Chip Sync Input. The MSYNCI pin of all the p
SYNCIN1 I CIC Decimation/Carrier NCO Update Sync. Can be used to synchronize the CIC Section, carrier NCO update, or
SYNCIN2 I FIR/Timing NCO Update/AGC Gain Update Sync. Can be used to synchronize the FIR, T
SYNCOUT O S trobe Output. This synchronization signal is generated by the μP
DATARDY is asserted for one PROCCLK cycle during the first clock cycle that data is available on the parallel out busses. See Output Section.
OEAH is high.
OEAL is high.
OEBH is high.
OEBL is high.
least significant bytes of AOUT and BOUT. SEL2 is the MSB.
ready for reading.
ency, timing error and AGC information can be sequenced
in programmable order. See Output Section and Microprocessor Write Section.
and AGC information can be sequenced in pr Section.
Section.
impedance.
Converter on the rising edge of this signal. See Microprocessor Write Section.
Programmable Down Converter on the falling edge of this signal. See Microprocessor Read Section.
REFCLK. REFCLK frequency must be less than or equal to PROCCLK/2.
asynchro back end processing operating under PROCCLK. This output sync signal from one part is connected to the MSYNCI signal of all the HSP50214Bs.
NOTE: MSYNCI must be connected t
both. See High.
gain update, or any combination of the above. See the Multiple Chip Synchronization Section and Control Words 7, 8, and 10 in the Microprocessor Write Section. Active High.
generated by PROCLK or CLKIN (see Control Word 0 and Control Word 24 in the Microprocessor Write Section). Active High.
nous. MSYNCO is the synchronization signal between the input section operating under CLKIN and the
the Multiple Chip Synchronization Section and Control Word 0 in the Microprocessor Write Section. Active
ogrammable order. See Output Section and Microprocessor Write
ta strobes. See Output Section and Microprocessor Write Section.
Write Section. A2 is the MSB.
arts should be tied to the MSYNCO of one part.
o an MSYNCO signal for operation.
om the Buffer RAM Output Port is sent to the
n by Control Word 20 in the Microprocessor Write
tector. The timing error is computed relative to
iming NCO update, AGC
interface for synchronizing multiple parts. Can be
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FN4450.4
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6
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AGCGNSEL
PROCCLK
GAINADJ(2:0)
ENI
IN(13:0)
DETECT
μPROCESSOR
INTERFACE
CLKIN
INPUT
LEVEL
TO
SECTION
MIXER
5TH ORDER
CIC DECIMATE FROM 4-32
TO OUTPUT FORMATTER AND MICROPROCESSOR
0 TO 5 HALFBAND FILTER;
DECIMATION UP TO 32
INTERFACE
(CO = 1;
= 0)
C
n
255-TAP
PROGRAMMABLE
FIR FILTER
(DECIMATE UP TO 16)
AGCOUT
SHIFT
AGC
A
LIMIT
FILTER
POLYPHASE
RE-SAMPLER
LOOP
FILTER
INTERPOLATE
BY 2/4
HALFBAND
FILTERS
ERROR
DETECT
CARTESIAN
TO
POLAR
I
I2Q2+
Q
⎛⎞
----
atan
⎝⎠
I
Q
DATARDY INTRRP
AOUT(15:0) BOUT(15:0)
OEAH OEAL OEBH OEBL
HSP50214B
(C
COS
COF
COFSYNC
(CARRIER TRACKING)
SOF
SOFSYNC
REFCLK
RD
WR A(2:0) C(7:0)
May 1, 2007
FN4450.4
SIN NCO
MICROPROCESSOR
READ/WRITE
CONTROL
SECTION
OUTPUT SECTION DISCRIMINATOR SECTION INPUT SECTION LEVEL DETECT SECTION SYNCHRONIZATION SECTION CARRIER NCO SECTIONS CIC, HALFBAND FILTER, AND FIR SECTIONS DIGITAL AGC SECTION RE-SAMPLER/INTERPOLATION HALFBAND SECTION TIMING NCO
= 1;
O
= 0)
C
n
(SYMBOL TRACKING)
SHIFT
NCO
FILTER
POLYPHASE
DIFFERENCE
CLKIN
PROCCLK
DISCRIMINATOR
dθ
PROGRAMMABLE
td
63-TAP
FIR FILTER
TIMING ERROR
AGCOUT
A
CHIP
SYNCHRONIZATION
CIRCUITRY
BACK END
SYNCHRONIZATION
CIRCUITRY
FRONT END
SYNCHRONIZATION
CIRCUITRY
OUTPUT FORMATTER
INTRRP SEL(2:0)
SEROUTA SEROUTB SERCLK
SERSYNC SEROE
MSYNCI SYNCOUT MSYNCO
SYNCIN2
SYNCIN1
FIGURE 1. FUNCTIONAL BLOCK DIAGRAM OF THE HSP50214B PROGRAMMABLE DOWNCONVERTER
HSP50214B
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Functional Description
The HSP50214B Programmable Downconverter (PDC) is an agile digital tuner designed to meet the requirements of a wide variety of communications industry standards. The PDC contains the processing functions needed to convert sampled IF signals to baseband digital samples. These functions include LO generation/mixing, decimation filtering, programmable FIR shaping/bandlimiting filtering, resampling, Automatic Gain Control (AGC), frequency discrimination and detection as well as multi-chip synchronization. The HSP50214B interfaces directly with a DSP microprocessor to pass baseband and status data.
A top level functional block diagram of the HSP50214B is sh
own in Figure 1. The diagram shows the major blocks and
multiplexers used to reconfigure th
e data path for various architectures. The HSP50214B can be broken into 13 sections: Synchronization, Input, Input Level Detector, Carrier Mixer/Numerically Control Oscillator (NCO), CIC Decimating Filter, Halfband Decimating Filter, 255-Tap Programmable FIR Filter, Automatic Gain Control (AGC), Re-sampler/Halfband Filter, Timing NCO, Cartesian to Polar Converter, Discriminator, and Output Sections. All of these sections are configured through a microprocessor interface.
The HSP50214B has three clock inputs; two are required and on
e is optional. The input level detector , carrier NCO, and CIC decimating filter sections operate on the rising edge of the input clock, CLKIN. The halfband filter , p rogrammable FIR filter, AGC, Re-Sampler / Halfband filters, timing NCO, di
scriminator, and ou tput sections ope ra te on the ri si ng edge of PROCCLK. The third clock, REFCLK, is used to generate timing error information.
NOTE: All of the clocks may be asynchronous.
PDC Applications Overview
This section highlights the motivation behind the key programmable features from a communications system level perspective. These motivations will be defined in terms of ability to provide DSP processing capability for specific modulation formats and communication applications. The versatility of the Programmable Downconverter can be intimidating because of the many Control Words required for chip configuration. This section provides system level insight to help allay reservations about this versatile DSP product. It should help the designer capitalize on the greatest feature of the PDC - VERSATILITY THROUGH PROGRAMMABILITY. It is this feature, when fully understood, that brings the greatest return on design investment by offering a single receiver design that can process the many waveforms required in the communications marketplace.
FDM Based Standards and Applications
Table 1 provides an overview of some common frequency division multiplex (FDM) base station applications to which the PDC can be
applied. The PDC provides excellent selectivity
for frequency division multiple access (FDMA) signals. This high selectivity is achieved with 0.012Hz resolution frequency control of the NCO and the sharp filter responses capable with a 255-tap, 22-bit coefficient FIR filter . The 16-bi t resolution out of the Cartesian to Polar Coordinate Converter are routed to the frequency detector, which is follow ed by a 63-t ap, 22-bit coefficient FIR filter structure for facilitating FM and FSK detection. The 14-bit input resolution is the smallest bit resolution found throughout the conversion and filtering sections, providing excellent dynamic range in the DSP processing. A unique input gain scaler adds an additional 42dB of range to the input level variation, to compensate for changes in the analog RF front end receive equipment. Synchronization circuitry allows precise timing control of the base station reconfiguration for all receive channels simultaneously. Portions of this table were corroborated with reference [2].
TABLE 1. CELLULAR PHONE BASE STA TION
STANDARD
RX BAND
CHANNEL
BW (kHz)
# TRAFFIC
CHANNELS
MODULA-
DEVIATION
CONTROL
MOD
DEVIATION
CONTROL
HANNEL
C
APPLICATIONS USING FDMA
(MHz)
VOICE
TION
PEAK
(kHz)
ULA­TION
PEAK
(kHz)
RATE
(Kbps)
AMPS (
IS-91)
824-849 925-940 453-458
832 600
FSK FSK FSK FSK FSK
MCS-L1 MCS-L2
30 25.0
12.5
1200
FM FM FM FM FM
12 5 5 4 9.5
8 4.5 3.5 2.5 6.4
10 0.3 1.2 5.3 8
NMT-400 NMT-900 C450
890-915
12.5 200
1999
451-456 871-904
25
20.0
10.0 222
444
ETACS NTACS
915-925
25.0
12.5
1240
800
TDM Based Standards and Applications
Table 2 provides an overview of some common Time D ivision Multiplexed (TDM) base station applications to which the PDC can be ap applications, such as North American TDMA (IS136), where 30kHz is the received band of interest for the PCS basestation, the PDC offers 0.012Hz frequency resolution in downconversion in addition to α = 0.35 matched (programmable) filtering capability. The π/4 DPSK modulation can be processed using the PDC Cartesian to Polar coordinate converter and dφ/dt detecto r circuitry or by processing the I/Q samples in the DSP μP. The PDC provides
plied. For time division multiple access (TDMA)
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HSP50214B
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the ability to change the received signal gain and frequency, synchronous with burst timing. The synchronous gain adjustment allows the user to measure the power of the signal at the A/D at the end of a burst, and synchronously reload that same gain value at the arrival of the next user burst.
For applications other than cellular phones (where the prea
mbles are not changed), the PDC frequency discriminator output can be used to obtain correlation on the preamble pattern to aid in burst acquisition.
TABLE 2. CELLULAR BASESTATION APPLICATIONS USING
CHANNEL BW (kHz) 200 200 30
# TRAFFIC CHANNELS 8 16 3
VOICE MODULATION GMSK GMSK
CHANNEL RATE (Kbps) 270.8 270.8 48.6
CHANNEL RATE (Kbps) 270.8 270.8 48.6
Several applications are combinations of frequency and time domai TDMA signal that is frequency hopped. The individual channels contain Gaussian MSK modulated signals. The PDC again offers the 0.012Hz tuning resolution for de­hopping the received signal. The combination of halfband and 256-tap programmable, 22-bit coefficient FIR filters readily performs the necessary matched filtering for demodulation and optimum detection of the GMSK signals.
TDMA
STANDARD GSM PCN IS-54
TYPE Cellular Cellular Cellular
BASESTATION RX
BAN
D (MHz)
CONTROL
MODULATION
n multiple access schemes. For example, GSM is a
935-960 1805-1880 824-849
π/4
DQPSK
GMSK GMSK
π/4
DQPSK
CDMA Based Standards and Applications
For Code Division Multiple Access (CDMA) type signals, the PDC offers the ability to have a single wideband RF front end, from which it can select a single spread channel of interest. The synchronization circuitry provides for easy control of multiple PDC for applications where multiple received signals are required, such as base-stations.
In IS-95 CDMA, the receive signal bandwidth is app
roximately 1.2288MHz wide with many spread spectrum channel in the band. The PDC supplies the downconversion and filtering required to receive a single RF channel in the presence of strong adjacent interference. Multiple PDC’s would be sourced from a single receive RF chain, each processing a different receive frequency channel. The despreader would usually follow the PDC. In some very specific applications, with short, fixed codes, the filtering and despreading may be possible with innovative use of the programmable, 22-bit coefficient FIR filter. The PDC offers
0.012Hz resolution on tuning to the desired receive channel and excellent rejection of the portions of the band not being
processed, via the halfband and 255-tap programmable, 22­bit coefficient FIR filter.
Traditional Modulation Formats
AM, ASK, FM AND FSK
The PDC has the capability to fully demodulate AM and FM
lated waveforms. The PDC outputs 15-bits of amplitude
modu or 16-bits of frequency for these modulation formats. The FM discriminator has a 63-tap programmable, 22-bit coefficient FIR filter for additional signal conditioning of the FM signal. Digital versions of these formats, ASK and FSK are also readily processed using the PDC. Just as in the AM modulated case, ASK signals will use 15-bit magnitude output of the Cartesian to Polar Coordinate converter. Multi-tone FSK can be processed several ways. The frequency information out of the discriminator can be used to identify the received tone, or the filter can be used to identify and power detect a specific tone of the received signal. AMPS is an example of an FM application.
PM AND PSK
The PDC provides the downcon matched filtering and coordinate conversion required for demodulation of PM and PSK modulated waveforms. These modulation formats will require external carrier and symbol timing recovery loop filters to complete the receiver design. The PDC was designed to interface with the HSP50210 Digital Costas Loop to implement the carrier phase and symbol timing recovery loop filters (for continuous PSK signals-not burst).
Digital modulation formats that combine amplitude and ph
ase for symbol mapping, such as m-ary QAM, can also be downconverted, demodulated, and matched filtered. The received symbol information is provided with 16-bits of resolution in either Cartesian or Polar coordinates to facilitate remapping into bits and to recover the carrier phase. External Symbol mapping and Carrier Recovery Loop Filtering is required for this waveform.
version, demodulation,
Resampling and Interpolation Filters
Two key features of the resampling FIR filter are that the re­sampler filter allows the output sample rate to be programmed with millihertz resolution and that the output sample rate can be phase locked to an independent separate clock. The re-sampler frees the front end sampling clocks from having to be synchronous or integrally related in rate to the baseband output. The asynchronous relationship between front end and back end clocks is critical in applications where ISDN interfaces drive the baseband interfaces, but the channel sample rates are not related in any way. The interpolation halfband filters can increase the rate of the output when narrow frequency bands are being processed. The increase in output rate allows maximum use of the programmable FIR while preserving time resolution in the baseband data.
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HSP50214B
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14-Bit Input and Processing Resolution
The PDC maintains a minimum of 14-bits of processing resolution through to the output, providing over 84dB of dynamic range. The 18-bits of resolution on the internal references provide a spurious floor that is better than 98dBc. Furthermore, the PDC provides up to 42dB of gain scaling to compensate for any change in gain in the RF front end as well as up to 96dB of gain in the internal PDC AGC. This gain maximizes the output resolution for small signals and compensates for changes in the RF front end gain, to handle changes in the incoming signal.
Summary
The greatest feature of the PDC is its ability to be reconfigured to process many common standards in the communications industry. Thus, a single hardware element can receive and process a wide variety of signals from PCS to traditional cellular, from wireless local loop to SATCOM. The high resolution frequency tuning and narrowband filtering are instrumental in almost all of the applications.
Multiple Chip Synchronization
Multiple PDCs are synchronized using a MASTER/SLAVE configuration. One part is responsible for synchronizing the front end internal circuitry using CLKIN while another part is responsible for synchronizing the backend internal circuitry using PROCCLK.
The PDC is synchronized with other PDCs using lines: SYNCOUT, SYNCIN1, SYNCIN2, MSYNCO, and MSYNCI. Figure 2 shows the interconnection of these five signals for multiple chip synchronization where different sources are used
PDC A is the Master sync through MSO. PDC B configures the CLKIN sync through SYNCIN1. PDC A configures the PROCCLK sync through SYNCIN2.
HSP50214B
(MASTER
SYNCIN2)
for CLKIN and PROCCLK.
AB
MSYNCO
MSYNCI
SYNCOUT
SYNCIN2
SYNCIN1
ALL OTHER SYNCIN1 ALL OTHER SYNCIN2 ALL OTHER MSI
FIGURE 2. SYNCHRONIZATION CIRCUIT
SYNCOUT for PDC B should be set to be synchronous with C
LKIN (Control Word 0, Bit 3 = 0. See the Microprocessor Write Section). SYNCOUT for PDC B is tied to the SYNCIN1 of all the PDCs. The SYNCIN1 can be programmed so that
five control
HSP50214B
MSYNCO
MSYNCI
SYNCOUT
SYNCIN2
SYNCIN1
(MASTER SYNCIN1)
the carrier NCO and/or the 5th order CIC filter of all PDCs can be synchronously loaded / updated using SYNCIN1. See Co
ntrol Word 0, Bits 19 and 20 in the Microprocessor W ri te
Section for details. SYNCOUT for one of the PDC’s other than PDC B, should
be
set for PROCCLK (bit 3 = 1 in Control Word 0). This output signal is tied to the SYNCIN2 of all PDCs. The SYNCIN2 can be programmed so that the AGC updates its accumulator with the content s in the master registers (Control Word 8, Bit 29 in the Microprocessor Write Section). SYNCIN2 is also used to load or reset the timing NCO using bit 5, Control Word 11. The halfband and FIR filters can be reset on SYNCIN2 using Control Word 7, Bit 21. The MSYNCO of one of the PDCs is then used to drive the MSYNCI of all the PDCs (including its own).
For application configuration
s where CLKIN and PROCCLK have the same source, SYNCIN1 and SYNCIN2 can be tied together. However, if different enabling is desired for the front end and backend processing of the PDC’s, these signals can still be controlled independently.
In the HSP50214B, the Control Word 25 reset signal has be
en extended so that the front end reset is 10 CLKIN periods wide and the back end reset is 10 PROCCLK periods wide. This guarantees that no enables will be caught in the pipelines. In addition, the SYNCIN1 internal reset signal, which is enabled by setting Control Word 7, Bit 21 = 1, has been extended to 10 cycles.
In summary, SYNCIN1 is used to update carrier phase of
fset, update carrier center frequency, reset CIC decimation counters and reset the carrier NCO (clear the feedback in the NCO). SYNCIN2 is used to reset the HB filter, FIR filter, re-sampler / HB state machines and the output FIFO, load a ne
w gain into the AGC and load a new re-sampler NCO
center frequency and phase offset.
Input Section
The block diagram of the input controller is provided in Figure 3. The input can support offset binary or two’s complement data and can be o interpolated mode (see Control Word 0 from the Microprocessor Write Section). The gated mode takes one sample per clock when the input enable (ENI) is asserted. The gated mode allows the user to synchronize a low speed sampling clock to a high speed CLKIN.
The interpolated mode allows the user sample rate and to zero-stuff the data prior to filtering. This zero stuffing effectively interpolates the input signal up to the rate of the input clock (CLKIN). This interpolated mode allows the part to be used at rates where the sampling frequency is above the maximum input rate range of the halfband filter section, and where the desired output bandwidth is too wide to use a Cascaded Integrator Comb (CIC) filter without significantly reducing the dynamic range.
perated in gated or
to input data at a low
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See Figures 4 to 7 for an interpolated input example, detailing the associated spectral results.
Interpolation Example:
The specifications for the interpolated input example are: CLKIN = 40MHz
Input Sample Rate = 5MSPS PROCCLK = 28MHz Interpolate by 8, Decimate by 10 Desired 85dB dynamic range output bandwidth = 500kHz
Input Level Detector
The Input Level Detector Section measures the average magnitude error at the PDC input for the microprocessor by comparing the input level against a programmable threshold and then integrating the result. It is intended to provide a gain error for use in an AGC loop with either the RF/IF or A/D converter stages (see Figure 8). The AGC loop includes Input Level Detector an external gain control amplifier (or attenuator). The input samples are rectified and added to a threshold
IN(13:0)
INPUT FORMAT
INPUT
FORMAT
GAINADJ(2:0)
, the microprocessor and
LEVEL
DETECT
REG
REG
INPUT LEVEL DETECTOR STATUS (0)
14
14
18
NCO††
EN
programmed via the microprocessor interface, as shown in Figure 9. The bit weighting of the data path through the input threshold detector is shown in Figure 10. The threshold is a signed number, so it should be set to the inverse of the de to zero if the average input level is desired instead of the error. The sum of the threshold and the absolute value of the input is accumulated in a 32-bit accumulator. The accumulator can handle up to 2 overflow. The integration time is controlled by an 18-bit counter. The integration counter preload (ICPrel) is programmed via the microprocessor interface through Control Word 1. Only the upper 16-bits are programmable. The 2 LSBs are always zero. Control Word 1, Bits 29-14 are programmed to:
ICPrel N()41+=
where N is the desired integration period, defined as the nu
mber of input samples to be integrated. N must be a
multiple of 4: [0, 4, 8, 12, 16 .... , 2
INPUT_THRESH INTG_MODE INTG_INTEVAL
15
REGREG
15
18
LIMIT
DELA Y 3
3
sired input level. The threshold can be set
18
samples without
(EQ. 1)
18
].
MUX
SHIFT
4
BYPASS
CIC
ENI
INTERP
CONTROL WORD 0 CONTROL WORD 1
CLKIN
BYPASS
5MHz
CLKIN = 5MHz
Without Interpolation, the CIC bypass path exceeds the HB/FIR filter inp
ut sample rate and the CIC filter path will not yield the desired
85dB dynamic range band width of 500kHz.
CIC
FILTER
MIN. R = 4
FIGURE 4. STATEMENT OF THE PROBLEM
PROCCLK = 28MHz
HB/FIR FILTER
MUX
MAX. fS = 4MHz
(EXCEEDED IN BYPASS PATH)
CONTROL
LOGIC
FIGURE 3. BLOCK DIAGRAM OF THE INPUT SECTION
500kHz = 85dB
BANDWIDTH (NOT ACHIEVED WITH CIC FILTER PATH)
INPUT_MODE INPUT_FMT INPUT_THRESH INTG_MODE INTG_INTEVAL
DELA Y 3
4
†† See NCO Section for more details.
8 (0 STUFF) = 40MHz
5MHz
CLKIN = 40MHz
FIGURE 5. BLOCK DIAGRAM OF THE INTERPOLATION
CIC FILTER
10
Controlled via microprocessor interface.
4MHz
R = ↓10
APPROACH
HB/FIR FILTER
500kHz = 85dB BANDWIDTH
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f
S
5MHz 10MHz 15MHz 20MHz 25MHz 30MHz 35MHz 40MHz 45MHz 50MHz
5MHz 10MHz 15MHz 20MHz 25MHz 30MHz 35MHz 40MHz
2f
3f
S
THE INPUT DATA SPECTRUM SAMPLED AT RATE R = f
4f
S
5f
S
S
6f
S
7f
8f
S
S
f’S f’S/2 f’S/4 f’S/8 3f’S/8 5f’S/8 7f’S/8 3f’S/4
9f
S
10f
S
S
FIGURE 6. INTERPOLATION SPECTRUM: INTERPOLATE BY 8 THE INPUT DATA WITH ZERO STUFFING; SAMPLE AT RATE R = f’s
8MHz 12MHz 16MHz 20MHz 24MHz 28MHz 32MHz 36MHz 40MHz
4MHz
DECIMATE BY 10 AND CIC FILTER; SAMPLE AT RATE R = f’s/10
85dB DYNAMIC RANGE BANDWIDTH
4MHz2MHz1MHz 3MHz
CIC FILTER FREQUENCY RESPONSE
CIC FILTER ALIAS PROFILE
O.5MHz
FIGURE 7. ALIAS PROFILE AND THE 85dB DYNAMIC RANGE BANDWIDTH
INPUT
μPROC
DAC
IF
GCA
A/D
INPUT LEVEL DETECTOR (24-BIT ERROR VALUE)
THRESH
PDC
FIGURE 8. PROCESSOR BASED EXTERNAL IF AGC
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INPUT
|X|
R E
G
16
COUNTER
CONTINUOUS SINGLE
ACCUMULATOR
18
2
17
2
16
2
15
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
μPROC READ
0
18
2
17
2
16
2
15
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-6dB
-12dB
-18dB
-24dB
-30dB
-36dB
-42dB
-48dB
-54dB
-60dB
-66dB
-72dB
-78dB
IN(13:0)
INPUT_THRESHOLD
INTEGRATION_INTERVAL
INTEGRATION_MODE
Controlled via microprocessor interface.
A/D
OUTPUT
f
0
2
S
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
INPUT
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
0 2 2 2 2 2 2 2 2 2 2 2 2 2
MAGNITUDE
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-11
-12
-13
GATING
LOGIC
START
CLKIN
THESHOLD
0
-2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
FIGURE 10. INPUT THRESHOLD DETECTOR BIT WEIGHTING
+ +
“0”
FIGURE 9.
READ CODE A(2:0)
PORTS
000 010001
ACCUMULATOR
32
CLKIN
R E G
R E G
ADDR(2:0)
24
M U X
TO μPROC
8
The integration period counter can be set up to run continuously or to count down and stop. Continuous integration counter operation lets the counter run, with sampling occurring every time the counter reaches zero. Because the processor samples the detector read port asynchronous to the CLKIN, data can be missed unless the status bit is monitored by the processor to ensure that a sample is taken for every integration count down sequence.
Additionally , in the HSP50214B, the ability to alig n the st
art/restart of the input level detector integration period with an external event is provided. This allows the sync signals, which are synchronized to external events, to be used to align all of the gain adjustments or measurements. If Control W ord 27, Bit 17 is set to a logic one, the SYNCIN1 signal will cau se the input level detector to start/restart its integration peri od. If Control Word 27, Bit 17 is set to a logic zero, control of the start/restart of the input level detector integration period does not respond to SYNCIN1.
In the count down and stop mode, the microprocessor read command
s can be synchronized to system events, such as the start of a burst for a TDMA application. The integration counter can be started at any time by writing to Control Word 2. At the end of the integration period (counter = 0000), the upper 23-bits of the accumulator are transferred to a holding register for reading by the microprocessor. Note that it is not the restarting of the counter (by writing to Control Word 2) that latches the current value, but the end of the integration count. When the accumulator results are latched, a bit is set in the Status Register to notify the processor. Reading the most significant byte of the 23-bits clears the status bit. See the Microprocessor Read Section. Figure 11 illustrates a typical AGC detection process.
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Typically, the average input error is read from the Input Level Detector port for use in AGC Applications. By setting the threshold to 0, however, the average value of the input signal can be read directly. The calculation is:
dBFS
RMS
20() 1.111()level()N()16()()[]log=
(EQ. 2)
where “level” is the 24-bit value read from the 3 level Detector Registers and
“N” is the number of samples to be integrated. Note that to get the RMS value of a sinusoid, multiply the average value of the rectified sinusoid by 1.111. For a full scale input sinusoid, this yields an RMS value of approximately 3dBf
NOTE: 1.111 scales the rectified sinusoid average (2/π) to 1/ √2
.
A) INPUT SIGNAL
AMPLITUDE
C) THRESHOLD
AMPLITUDE
E) DETECTOR OUTPUT
AMPLITUDE
FIGURE 11. SIGNAL PROCESSING WITHIN LEVEL DETECTOR
.
S
B) RECTIFIED SIGNAL
AMPLITUDEAMPLITUDE
D) ACCUMULATOR INPUTS
F) CLOSED LOOP STEADY STATE
(CONSTANT INPUT)
AMPLITUDE
In the HSP50214B, the polarity of the LSB’s of the integration period pre-load is selectable. If Control Word 27, Bit 23 is set to a logic one, the two LSB’s of the integration period preload are set to logic ones. This allows a power of two to be set for the integration period, for easy normalization in the processor. If Control Word 27, Bit 23 is set to a logic zero, then the two LSB’s of the integration period preload are set to zeros as in the HSP50214.
Carrier Synthesizer/Mixer
The Carrier Synthesizer/Mixer Section of the HSP50214B is shown in Figure 12. The NCO has a 32-bit phase accumulator, a 10-bit phase offset adder, and a sine/cosine ROM.
The frequency of the NCO is the sum of a center frequency Control Word, loaded via the microprocessor interface (Control Word 3, Bits 0 to 31), and an offset frequency, loaded serially via the COF and COFSYNC pins. The offset frequency can be zeroed in Control Word 0, Bit 1. Both frequency control terms are 32-bits and the addition is
modulo 2
32
. The output frequency of the NCO is computed
as:
fCfS* N 232() ,=
(EQ. 3)
or in terms of the programmed value:
NINTf
C
232fS⁄×[]
HEX
, =
where N is the 32-bit sum of the terms, f
is the frequency of the carrier NCO sinusoids, fS is
C
center and offset frequency
(EQ. 3A)
the input sampling frequency, and INT is the integer of the computation. See the Microprocessor Write Section on instructions for writing Control Word 3.
TO MIXERS
PHASE
ACCUMULATOR
ENI
18 18
REG
REG
SIN/COS
ROM
18
+
REG
SINCOS
CARRIER
PHASE
STROBE
R
R
10
E G
MUX
CARRIER
E
PHASE
G
OFFSET
CLEAR
0
R E G
PHASE
ACCUM
+
COF
ENABLE
COFSYNC
COF
SYNCIN1
MUX
32
COF
REG
SYNC REG
SHIFT REG
SYNC
CIRCUITRY
32
0
CF
REG
CARRIER
FREQUENCY
STROBE
CARRIER FREQUENCY (f
)
C
CARRIER LOAD ON UPDATE
Controlled via microprocessor interface.
FIGURE 12. BLOCK DIAGRAM OF NCO SECTION
For example, if N is 3267 (decimal), and f
is 65MHz, then fC
S
is 49.44Hz. If received data is modulated at a carrier frequency of 10MHz, then the synthesizer/mixer should be programmed for N = 27627627 (hex) or D89D89D8 (hex).
Because the input enable, ENI, controls the operation of the pha
se accumulator, the NCO output frequency is computed
relative to the input sample rate, f
, not to f
S
CLKIN
. The frequency control, N, is interpreted as two’s complement because the output of the NCO is quadrature. Negative frequency L.O.s select the upper sideband; positive freq uency L.O.s select the lower sideband. The range of the NCO is
-f
/2 to +fS /2. The frequency resolution of the NCO is fS /(232)
S
or approximately 0.015Hz when CLKIN is 65MSPS and ENI is tied low.
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The phase of the Carrier NCO can be shifted by adding a 10­bit phase offset to the MSB’s (modulo 360o) of the output of th
e phase accumulator. This phase offset control has a resolution of 0.35 complement from -180
o
to 360
φ
(0 to 2π). The phase offset is given by:
2π PO 210⁄()× 29()PO 291()≤≤–();=
OFF
o
and can be interpreted as two’s
o
to 180o (-π to π) or as binary from 0
512 to 511–()
(EQ. 4)
or, in terms of the parameter to be programmed:
PO INT 2
10
φ
()⁄]
OFF
HEX
π– φ
OFF
π<<();[=
(EQ. 4A)
where PO is the 10-bit two’s complement value loaded into the Phase Offset Register (Control Word 4, Bits 9-0). For example, a value of 32 (decimal) loaded into the Phase Offset Register would produce a phase offset of 1 1.25 would produce an offset of 180
o
o
. The phase offset is loaded via
and a value of -512
the microprocessor interface. See the Microprocessor Write Section on instructions for writing Control Word 4.
The most significant 18-bits from th
e phase adder are used as the address a sin/cos lookup table. This lookup table maps phase into sinusoidal amplitude. The sine and cosine values have 18-bits of amplitude resolution. The spurious components in the sine/cosine generation are at least
-102dBc. The sine and cosine samples are routed to the mixer section where they are multiplied with the input samples to translate the signal of interest to baseband.
The mixer multiplies the 14-bit i
nput by the 18-bit quadrature
sinusoids. The mixer equations are:
I
OUTIIN
Q
OUTIIN
ωc()cos×=
ωc()sin×=
(EQ. 5)
(EQ. 5A)
The mixer output is rounded symmetrically to 15-bits. To allow the frequency and phase of multiple parts to be
ated synchronously, two set s of registers are used for
upd latching the center frequency and phase offset words. The offset phase and center frequency Control Words are first loaded into holding registers. The contents of the holding registers are transferred to active registers in one of two ways. The first technique involves writing to a specific Control Word Address. A processor write to Control Word 5, transfers the center frequency value to the active register while a processor write to Control Word 6 transfers the phase offset value to the active register.
The second technique, designed for synchronizing updates to multipl
e parts, uses the SYNCIN1 pin to update the active registers. When Control Word 1, Bit 20 is set to 1, the SYNCIN1 pin causes both the center frequency and Phase Offset Holding Registers to be transferred to active registers. Additionally, when Control Word 0, Bit 0 is set to 1, the feedback in the phase accumulator is zeroed when the transfer from the holding to active register occurs. This feature provides
synchronization of the phase accumulator starting phase of multiple parts. It can also be used to reset the phase of the NCO synchronous with a specific event.
The carrier offset frequency is loaded using the COF and COFSYN
C pins. Figure 13 details the timing relationship between COF, COFSYNC and CLKIN. The offset frequency wo
rd can be zeroed if it is not needed. Similarly, the Sample Offset Frequency Register controlling the Re­Sampler NCO is loaded via the SOF and SOFSYNC pins. The procedure for loading data through the two pin NCO interfaces is identical except that the timing of SOF and SOFSYNC is relative to PROCCLK.
CLKIN
COFSYNC/
SOFSYNC
COF/
SOF
NOTE: Data must be loaded MSB first.
FIGURE 13. SERIAL INPUT TIMING FOR COF AND SOF INPUTS
MSB
LSB
MSB
Each serial word has a programmable word width of either 8, 16
, 24, or 32-bits (See Control Word 0, Bits 4 and 5, for the Carrier NCO programming and Control Word 11, Bits 3 and 4, for Timing NCO programming). On the rising edge of the clock, data on COF or SOF is clocked into an input shift register. The beginning of a serial word is designated by asserting either COFSYNC or SOFSYNC “high” one CLK period prior to the first data bit.
32
30 28 26
24
22 20 18
16
14 12 10
8
6
SHIFT COUNTER VALUE
4 2 0
ASSERTION OF
COFSYNC, SOFSYNC
DATA TRANSFERRED
TO HOLDING REGISTER
(8)
(24)
(16)
CLK TIMES
(32)
54504642383430262218141062
T
††
D
T
††
D
T
††
D
T
††
D
Serial word width can be: 8, 16, 24, 32 bits wide.
†† T
is determined by the COFSYNC, COFSYNC rate.
D
FIGURE 14. HOLDING REGISTERS LOAD SEQUENCE FOR
COF AND SOF SERIAL OFFSET FREQUENCY DATA
NOTE: Serial Data must be loaded MSB first, and COFSYNC or
SOFSYNC should not be asserted for more than one CLK cycle.
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NOTE: COF loading and timing is relative to CLKIN while SOF
loading and timing is relative to PROCCLK.
NOTE: T
can be 0, and the fastest rate is with 8-bit word width.
D
The assertion of the COFSYNC (or SOFSYNC) starts a count down from the programmed word width. On following CLKs, data is shifted into the register until the specified number of bits have been input. At this point the contents of the register are transferred from the Shift Register to the respecti ve 32-bit Holding Register. The Shift Register can accept new data on the following CLK. If the serial input word is defined to be less than 32-bits, it will be transferred to the MSBs of the 32-bit Holding Register and the LSBs of the Holding Register will be zeroed. See Figure 14 for details.
CIC Decimation Filter
The mixer output may be filtered with the CIC filter or it may be routed directly to the halfband filters. The CIC filter is use d to reduce the sample rate of a wideband signal to a rate that the halfbands and programmable filters can process, given the maximum computation speed of PROCCLK. (See Halfband and FIR Filter Sections for techniques to calculate this value).
Prior to the CIC filter, the output of the barrel shifter. The shifter is used to adjust the gain in 6dB steps to compensate for the variation in CIC filter gain with decimation. (See Equation 6). Fine gain adjustments must be done in the AGC Section. The shifter is controlled by the sum
of a 4-bit CIC Shift Gain word from the microprocessor and a 3-bit gain word from the GAINADJ(2:0) pins. The three bit value is pipelined to match the delay of the input samples. The sum of the 3 and 4-bit shift gain words saturates at a value of 15. Table 1 details the permissible values for the GAINADJ(2:0) barrel shifter control, while Figure 15 shows the permissible CIC Shift Gain values.
The CIC filter structure for the HSP50214B is fifth order; that is it ha
s five integrator/comb pairs. A fifth order CIC has 84dB of alias attenuation for output frequencies below 1/8 the CIC output sample rate.
mixer goes through a
15 14 13 12
11
10
9 8 7 6 5 4 3 2
CIC SHIFT GAIN (FROM PROCESSOR)
1 0
812202836445260
FIGURE 15. CIC SHIFT GAIN VALUES
The decimation factor of the CIC
8-BIT INPUT 10-BIT INPUT 12-BIT INPUT 14-BIT INPUT
164403224 645648
DECIMATION (R)
ALLOWABLE CIC SHIFT GAINS ARE BELOW THE CURVES
filter is programmed in Control Word 0, Bits 12 - 7. The C IC Shift Gain is programmed in Control Word 0, Bits 16-13. The CIC Bypass is set in Control Word 0, Bit 6. When bypassing the CIC filter, the
ENI signal must be de-asserted between samples, i.e., the CL KIN rate must be ≥ 2 • f
TABLE 3. GAIN ADJUST CONTROL AND CIC DECIMATION
VALUE
ΔGAIN
(dB) GAIN ADJ(2:0)
0 000 32
6 001 27 12 010 24 18 011 21 24 100 18 30 101 16 36 110 12 42 111 10
.
S
MAX. CIC
DECIMATION
CIC Gain Calculations
The gain through the CIC filter increases with increased decimation. The programmable barrel shifter that precedes the first integrator in the CIC is used to offset this variation. Gain variations due to decimation should be offset using the 4-bit CIC Shift Gain word. This allows the input signal level to be adjusted in 6dB steps to control the CIC output level.
The gain at each stage of the CIC is:
kRN,=
where R is the decimation factor and N is the number of stages. Th
e input to the CIC from the mixer is 15-bits, and the bit widths of the accumulators for the five stages in the HSP50214B are 40, 36, 32, 32, and 32, as shown in Figure 16. This limits the maximum decimation in the CIC to 32 for a full scale input.
If R is 32, the gain through all five integrator stages is 32 (The gain through the last four CIC stages is 2
15
20
, through the
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(EQ. 6)
5
= 225.
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last 3 it is 215, etc.). The sum of the input bits and the growth bits cannot exceed the accumulator size. This means that for a decimation of 32 and 15 input bits, the first accumulator must be 15 + 25 = 40-bits.
Thus, the value of the CIC Shift Gain word can be calcul
ated:
SG = FLOOR 39 - [ IIN() - log
NOTE: The number of input bits is IIN. (If the number of bits into
the CIC filter is used, the value 40 replaces 39).
(R)5 for 4<R<32
2
for R = 4= 15
(EQ. 7)
For 14-bits, Equation 7 becomes:
SG FLOOR 25 log
15= for R 4=
R()5]for 4 R 32<<[=
2
(EQ. 8A)
For 12-bits, Equation 7 becomes:
SG FLOOR 27 log
15= for 4 R 5
R()5]for 5 < R < 40[=
2
(EQ. 8B)
For 10-bits, Equation 7 becomes:
SG FLOOR 29 log
R()5]for 6 < R < 52[=
2
for 4 R 615=
(EQ. 8C)
The CIC filter decimation counte
r can be loaded synchronous with other PDC chips, using the SYNCIN1 signal and the CIC External Sync Enable bit. The CIC external Sync Enable is set via Control Word 0, Bit 19.
Halfband Decimating Filters
The Programmable Down Converter has five halfband filter stages, as shown in Figure 17. Each stage decimates by 2 and filters out half of the available bandwidth. The first ha
lfband, or HB1, has 7 taps. The remaining halfbands; HB2, HB3, HB4, and HB5; have 11, 15, 19, and 23 taps respectively. The coefficients for these halfbands are given in Table 4. Figure 18 shows the frequency response of each of the halfband filters with respect to normalized frequency, F
. Frequency normalization is with respect to the input
N
sampling frequency of each filter section. Each stage is activated by their respective bit location (15-20) in Control Word 7. Any combination of halfband filters may be used, or all may be bypassed.
For 8-bits, Equation 7 becomes:
SG FLOOR 31 log
15= for 4 R 9
Figure 15 is a plot of Equations 8A throug
R()5]for 9 < R < 64[=
2
(EQ. 8D)
h 8D. The 4-bit CIC Shift Gain word has a range from 0 to 15. The 6-bit Decimatio
n Factor counter preload field, (R-1), has a range
from 0 to 63, limited by the input resolution as cited above.
Using the Input Gain Adjust Control Signals
The input gain offset control GAINADJ(2:0)) is provided to offset the signal gain through the part, i.e., to keep the CIC filter output level constant as the analog front end attenuation is changed. The gain adjust offset is 6dB per code, so the gain adjust range is 0 to 42dB. For example, if 12dB of attenuation is switched in at the receiver RF front end, a code of 2 would increase the gain at the input to the CIC filter up 12dB so that the CIC filter output would not drop by 12dB. This fixed gain adjust eliminates the need for the software to continually normalize.
One must exercise care when using this function as it can cause ove shifter from the gain adjust control signals is the equivalent of an extra bit of input. The maximum decimation in the CIC is reduced accordingly. With a decimation of 32, all 40-bits of the CIC are needed, so no input offset gain is allowed. As the decimation is reduced, the allowable offset gain increases. Table 3 shows the decimation range versus desired offset gain range. T able 3 assumes that the CIC Shift Gain has been programmed per Equation 7 or 8A.
rflow in the CIC filter. Each gain adjust in the
16
FN4450.4
May 1, 2007
OUTPUT SHIFTER BITS TAKEN WHEN CIC IS BYPASSED
-
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HSP50214B
HALFBAND
FILTER INPUT
f
= fS
1
F
HB1
= F
HB2
OR F
HB4
IN
= fS OR fS/2
OR F
HB1
OR F
HB2
/2
HB3
/2
HB1
/2
/2
= F
HB1
HB2
SECTION
FN = f
S
HALFBAND FILTER 4
0
HALFBAND FILTER 5
0
1
F
= F
5
HALFBAND FILTER 1
0
HALFBAND FILTER 2
0
1 F
HB2
HALFBAND FILTER 3
0
1 F
= F
HB3
1 F
= F
HB4
HB3
OR F
HB4
HALFBAND FILTER OUTPUT
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-11
-12
-13
-14
-15
-16
-17
-18
-19
-20
-21
-22
-23
-24
-25
-26
-27
-28
-29
-30
-31
ACC5
CIC
OUTPUT
0
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
-14
2
-15
2
-16
2
-17
2
-18
2
-19
2
-20
2
-21
2
-22
2
-23
2
CONTROL WORD 7, BIT 18 F
CONTROL WORD 7, BIT 15 F
N
CONTROL WORD 7, BIT 16
= F
F
N
CONTROL WORD 7, BIT 17 FN = F
HB3
= F
N
HB4
CONTROL WORD 7, BIT 19
Each halfband section decimates by 2.
FIGURE 17. BLOCK DIAGRAM OF HALFBAND FILTER
INPUT
(SHFT=0)
(SHFT=15)
0
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
-14
2
0
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
-14
2
2 2 2 2 2 2 2 2
ACC2
ACC3
ACC4
0
0
0
0
-1
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
-14
2
-15
2
-16
2
-17
2
-18
2
-19
2
-20
2
-21
2
-22
2
-23
2
-24
2
-25
2
-26
2
-27
2
-28
2
-29
2
-30
2
-31
2
-32
-33
-34
-35
-36
-37
-38
-39
-1
2
2
-2
-2
2
2
-3
-3
2
2
-4
-4
2
2
-5
-5
2
2
-6
-6
2
2
-7
-7
2
2
-8
-8
2
2
-9
-9
2
2
-10
-10
2
2
-11
-11
2
2
-12
-12
2
2
-13
-13
2
2
-14
-14
2
2
-15
-15
2
2
-16
-16
2
2
-17
-17
2
2
-18
-18
2
2
-19
-19
2
2
-20
-20
2
2
-21
-21
2
2
-22
-22
2
2
-23
-23
2
2
-24
-24
2
2
-25
-25
2
2
-26
-26
2
2
-27
-27
2
2
-28
-28
2
2
-29
-29
2
2
-30
-30
2
2
-31
-31
2
2
-32
2
-33
2
-34
2
-35
2
0
-1
2
2
-2
2
2
-3
2
2
-4
2
2
-5
2
2
-6
2
2
-7
2
2
-8
2
2
-9
2
2
-10
2
2
-11
2
2
-12
2
2
-13
2
2
-14
2
2
-15
2
2
-16
2
2
-17
2
2
-18
2
2
-19
2
2
-20
2
2
-21
2
2
-22
2
2
-23
2
2
-24
2
2
-25
2
2
-26
2
2
-27
2
2
-28
2
2
-29
2
2
-30
2
2
-31
2
2
ACC1
INPUT
NOTE: If 14 input bits are not needed, the gain adjust can be in
creased by one for each bit that the input is shifted down at the input. For example, if only 12-bits are needed, an offset range of 24dB is possible for a decimation of 24.
FIGURE 16. CIC FILTER BIT WEIGHTING
Since each halfband filter section decimates by 2, the total decimation through the halfband filter is given by:
DECHB2N=
(EQ. 9)
where N = Number of Halfband Filters Selected (1 - 5).
17
FN4450.4
May 1, 2007
0
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-20
-40
HSP50214B
-6dB BANDWIDTH
-60
-80
MAGNITUDE (dB)
-100
-120
HALFBAND FILTER 5 HALFBAND FILTER 4 HALFBAND FILTER 3 HALFBAND FILTER 2 HALFBAND FILTER 1
0.125 0.25 0.375 0.5
NORMALIZED FREQUENCY (FN)
FIGURE 18. HALFBAND FILTER FREQUENCY RESPONSE
0
ALIAS PROFILES
-20
-40
-60
-80
MAGNITUDE (dB)
-100
-120
HALFBAND FILTER 5
HALFBAND FILTER 4 HALFBAND FILTER 3 HALFBAND FILTER 2 HALFBAND FILTER 1
0.125 0.25 0.375 0.5 NORMALIZED FREQUENCY (FN)
-6dB BANDWIDTH
FIGURE 19. HALFBAND FILTER ALIAS CONSIDERATIONS
18
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May 1, 2007
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TABLE 4. HALFBAND FILTER COEFFICIENTS
COEFFICIENTS HALFBAND #1 HALFBAND #2 HALFBAND #3 HALFBAND #4 HALFBAND #5
C0 - 0.031303406 0.005929947 -0.00130558 0.000378609 -0.000347137 C1 0.000000000 0.000000000 0.000000000 0.000000000 0.000000000 C2 0.281280518 -0.049036026 0.012379646 -0.003810883 0.00251317 C3 0.499954224 0.000000000 0.000000000 0.000000000 0.000000000 C4 0.281280518 0.29309082 -0.06055069 0.019245148 -0.010158539 C5 0.000000000 0.499969482 0.000000000 0.000000000 0.000000000 C6 - 0.031303406 0.29309082 0.299453735 -0.069904327 0.03055191 C7 0.000000000 0.499954224 0.000000000 0.000000000 C8 -0.049036026 0.299453735 0.304092407 -0.081981659
C9 0.000000000 0.000000000 0.500000000 0.000000000 C10 0.005929947 -0.06055069 0.304092407 0.309417725 C11 0.000000000 0.000000000 0.500000000 C12 0.012379646 -0.069904327 0.309417725 C13 0.000000000 0.000000000 0.000000000 C14 -0.00130558 0.019245148 -0.081981659 C15 0.000000000 0.000000000 C16 -0.003810883 0.03055191 C17 0.000000000 0.000000000 C18 0.000378609 -0.010158539 C19 0.000000000 C20 0.00251317 C21 0.000000000 C22 -0.000347137
NOTE: While Halfband filters are typically selected starting with the last stage in the filter chain to give the maximum alias free ban
a higher throughput rate may be obtained using other filter combinations. See Application Note 9720, “Calculating Maximum Processing Rates of the PDC”.
dwidth,
Depending on the number of halfbands used, PROCCLK must operate at a minimum rate above the input sample rate, f
, to the halfband. This relationship depends on the
S
number of multiplies for each of the halfband filter stages. The filter calculations take 3, 4, 5, 6, and 7 multiplies per input for HB1, HB2, HB3, HB4, and HB5 respectively. If we keep the assumption that f
is the input sampling frequency,
S
then Equation 10 shows the minimum ratio needed.
)+
)+
HB5
)+
)+
)]/2T
(EQ. 10)
f
PROCCLK/fS
(6)(HB4)(2 (5)(HB3)(2 (4)(HB2)(2 (3)(HB1)(2
(HB4 + HB5) (HB3+HB4+HB5) (HB2+HB3+ HB4+HB5) (HB1+HB2+HB3+HB4+HB5)
([(7)(HB5)(2
where HB1 = 1 if this section is selected and 0 if it is bypassed;
HB2 = 1 if this section is selected and 0 if it is bypassed; HB3 = 1 if this section is selected and 0 if it is bypassed; HB4 = 1 if this section is selected and 0 if it is bypassed; HB5 = 1 if this section is selected and 0 if it is bypassed; T = number of Halfband Filters Selected. Th
e range for T is
from 0 to 5.
19
Examples of PROCCLK Rate Calculations
Suppose we enable HB1, HB3, and HB5. Using Figure 16, HB1= 1, HB3 = 1, and HB5 = 1. Since stage 2 and stage 4 are no
t used, HB2 and HB4 = 0. PROCCLK must operate
faster than (7x2+5x4+3x8)/8 = 7.25 times faster than f
.
S
If all five halfbands are used, then PROCCLK must operate at (7x2+6x4+5x8+4x16+3x32)/32 = 7.4375 times faster than f
S
255-Tap Programmable FIR Filter
The Programmable FIR filter can be used to implement real filters with even or odd symmetry, using up to 255 filter taps, or complex filters with up to 64 taps. The FIR filter takes advantage of symmetry in coefficients by summing data samples that share a common coefficient, prior to multiplication. In this manner, two filter taps are calculated per multiply accumulate cycle. Asymmetric filters cannot share common coefficients, so only one tap per multiply accumulate cycle is calculated. The filter can be effectively bypassed by setting the coefficient C coefficients, C
= 0.
N
= 1 and all other
0
FN4450.4
May 1, 2007
.
HSP50214B
www.BDTIC.com/Intersil
Additionally, the Programmable FIR filter provides for decimation factors, R, from 1 to 16. The processing rate of the Filter Compute Engine is PROCCLK. As a result, the frequency of PROCCLK must exceed a minimum value to ensure that a filter c alculatio n is complete before the result is required for output. In configurations which do not use decimation, one input sample period is available for filter calculation before an output is required. For configurations which employ decimation, up to 16 input sample periods may be available for filter calculation.
For real filter configurations, use Equatio calculate the number of taps availabl sample rate.
TAPS floor PROCCLK F
SYM) SYM()ODD#()[]
SAMP
for real filters, and
TAPS floor (PROCCLK F
SAMP
for complex filters, where floor is defined as the integer portion
of a number; PROCCLK is the compute clock; f = the FIR input sample rate; R = Decimation Factor; SYM = 1 for symmetrical filter, 0 for asymmetrical filter; ODD# = 1 for an odd number of filter taps, 0 = an even number of taps.
Use Equation 12A to calculate the maximum input rate.
F
SAMP
PROCCLK() R() R floor Taps()[[+[⁄ += SYM()ODD#()]1 SYM+()⁄]]
for real filters, and
F
SAMP
PROCCLK()R()[]R floor Taps()2()][+[]=
for complex filters, where floor[x], PROCCLK, f Decimation Factor, SYM, and ODD# are defined as in Equation 11A.
Use Equation 13 to calculate the maximum output sample rate for both real and complex
F
FIROUT
F
()R=
SAMP
filters.
The coefficients are 22-bits and are loaded using writes to Con
trol Words 128 through 255 (see Microprocessor Write Section). For real filters, the same coefficients are used by I and Q paths. If the filter is configured as a symmetric filter using Control Word 17, Bit 9, then coefficients are loaded starting with the center coefficient in Control Word 128 and proceeding to last coefficient in Control Word 128+n. The filter symmetry type can be set to even or odd symmetric, and the number of filter coefficients can be even or odd, as illustrated in Figure 20. Note that complex filters can also be realized but are only allowed to be asymmetric. Only the coef
ficients that are used need to be loaded.
ns 1 1A an d 11B to
e at a given input filter
S AMP
(EQ. 11A)
(EQ. 11B)
S AMP
(EQ. 12A)
(EQ. 12B)
, R =
(EQ. 13)
R⁄() R][()1 +(=
R() R) 2][=
I
E
N
T
COEFFICIENT VALUE COEFFICIENT VALUE
COEFFICIENT VALUE
V
A
C0
ODD SYMMETRIC
EVEN TAP FILTER
C0
ODD SYMMETRIC ODD TAP FILTER
C0
ASYMMETRIC
ODD TAP FILTER
C
C
I
L
U
E
C0
COEFFICIENT VALUECOEFFICIENT VALUE
EVEN SYMMETRIC EVEN TAP FILTER
C0
EVEN SYMMETRIC
ODD TAP FILTER
C0
COEFFICIENT VALUE
ASYMMETRIC
EVEN TAP FILTER
C
IMAGINARY
COEFFICIENT
R
CN-1
CN-1
Q
C
VALUE
Q(0)
E
A
L
COEFFICIENT NUMBER
CN-1
COEFFICIENT NUMBER
COEFFICIENT NUMBER
REAL FILTERS
C
I(0)
C
O
E
F
F
I
C
COMPLEX FILTERS
CN-1
Q(N-1)
COEFFICIENT NUMBER
C
I(N-1)
CN-1
COEFFICIENT NUMBER
CN
COEFFICIENT NUMBER
COEFFICIENT NUMBER
Definitions: Even Symmetric: h(n) = h(N-n-1) for n = 0 to N-1
Odd Symmetric: h(n) = -h(N-n-1) for n = 0 to N-1 Asymmetric: A filter with no coefficient symmetry. Even Tap filter: A filter where N is an even number. Odd Tap filter: A filter where N is an odd number. Real Filter: A filter implemented with real coefficients.
Complex Filters: A filter with quadrature coefficients.
FIGURE 20. DEMONSTRATION OF DIFFERENT TYPES OF
DIGITAL FIR FILTERS CONFIGURED IN THE PROGRAMMABLE DOWNCONVERTER
Automatic Gain Control (AGC)
The AGC Section provides gain to small signals, after the large signals and out-of-band noise have been filtered out, to ensure that small signals have sufficient bit resolution in the Resampling/Interpolating Halfband filters and the Output Formatter. The AGC can also be used to manually set the gain. The AGC optimizes the bit resolution for a variety of input amplitude signal levels. The AGC loop automatically adds gain to bring small signals from the lower bits of the 26­bit programmable FIR filter output into the 16-bit range of the
20
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May 1, 2007
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output section. Without gain control, a signal at -72dBFS = 20log
-12
(2
) at the input would have only 4-bits of
10
resolution at the output (12-bits less than the full scale 16-bits). The potential increase in the bit resolution due to processin
g gain of the filters can be lost without the use of
the AGC. Figure 23 shows the Block Diagram for the AGC Section.
The FIR filter data output is routed
to the Resampling and Halfband filters after passing through the AGC multipliers and Shift Registers. The outputs of the Interpolating Halfband filters are routed to the Cartesian to Polar coordinate converter. The magnitude output of the coordinate converter is routed through the AGC error detector, the AGC error scaler and into the AGC loop filter. This filtered error term is used to drive the AGC multiplier and shifters, completing the AGC control loop.
The AGC Multiplier/Shifter portion
of the AGC is identified in Figure 23. The gain control from the AGC loop filter is sampled when new data enters the Multiplier/Shifter. The limit
detector detects overflow in the shifter or the multiplier and saturates the output of I and Q data paths independently. The shifter has a gain from 0 to 90.31dB in
6.021dB steps, where 90.31dB = 20log
(2N), when N = 15.
10
The mantissa provides an additional 6dB of gain in
0.0338dB steps where 6.0204dB = 20log where X = 2
15
-1. Thus, the AGC multiplier/shifter transfer
[1+(X)2
10
-15
],
function is expressed as:
AGC Mult/Shift Gain 2
N
1X()2
15
],+[=
(EQ. 14)
where N, the shifter exponent, has a range of 0<N<15 and X, th
e mantissa, has a range of 0<X<(2
15
-1).
Equation 14 can be expressed in dB,
(AGC Mult/Shift Ga
in)dB 20log
2N1X()2
10
-15
]+[()=
(EQ. 14A)
The full AGC range of the Multiplier/Shifter is from 0 to
96.33
1dB (20log
[1+(215-1)2
10
-15
] + 20log10[215] = 96.331). Figure 21 illustrates the transfer function of the AGC multiplier versus mantissa control for N = 0. Figure 22 illustrates the complete AGC Multiplier/Shifter Transfer fu
nction for all values of exponent and mantissa control.
6
5
4
3
2
GAIN - LINEAR AND dB
1
0
0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240
AGC CONTROL MANTISSA VALUES (TIMES 256)
FIGURE 21. AGC MULTIPLIER LINEAR AND dB TRANSFER
FUNCTION
100
90
80
70
60
50
GAIN (dB)
40
30
20
10
0
064 128 192
AGC CONTROL WORD (MANTISSA x 256)
FIGURE 22. AGC GAIN CONTROL TRANSFER FUNCTION
G (dB)
G (LINEAR)
N = 15 N = 14
N = 13 N = 12
N = 11 N = 10
N = 9 N = 8
N = 7 N = 6 N = 5 N = 4
N = 3 N = 2 N = 1 N = 0
The Cartesian to Polar Coordinate converter accepts I and Q data and generates magnitude and phase data. The magnitude output is determined by the Equation 15:
The resolution of the mantissa was increased to 16-bits in t
he A Version, to provide a theoretical AM modulation level of -96dBc (depending on loop gain, settling mode and SNR). This effectively eliminates AM spurious caused by the AGC resolution.
For fixed gains, either set the upper and lower AGC limits to th
e same value, or set the limits to minimum and maximum
gains and set the AGC loop gain to zero.
r 1.64676 I
where the magnitude limits are determined by the maximum I
and Q signal levels into the Cartesian to Polar converter. Taking fractional 2’s complement representation, magnitude ranges from 0 to 2.329, where the maximum output is
r 1.64676 1.0()21.0()
The AGC loop feedback path consists of an error detector, error scali
ng, and an AGC loop filter. The error detector subtracts the magnitude output of the coordinate converter from the programmable AGC THRESHOLD value. The bit weighting of
21
2Q2
+ .=
2
+= 1.64676 1.414× 2.329==
(EQ. 15)
.
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May 1, 2007
HSP50214B
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the AGC THRESHOLD value (Control Word 8, Bits 16-28) is shown in T able 5. Note that the MSB is always zero. The range of the AGC THRESHOLD value is 0 to +3.9995. The AGC Erro
r Detector output has the identical range.
TABLE 5. AGC THRESHOLD (CONTROL WORD 8) BIT
28 27 26 25 24 23 22 21 20 19 18 17 16
22120
2
WEIGHTING
-12-22-32-42-52-62-72-82-92-10
. 2
The loop gain is set in the AGC Error Scaling circuitry, using the two programmable mantissas and exponents. The mantissa, M, is a 4-bit value which weights the loop filter input from 0.0 to 0.9375. The exponent, E, defines a shift
0
factor that provides additional weighting from 2
to 2
-15
. Together the mantissa and exponent define the loop gain as given by,
AGC Loop Gain M
where M E
is a 4-bit binary value ranging from 0 to 15. Table 7 and
LG
=
LG
is a 4-bit binary value ranging from 0 to 15 , an d
LG
8 detail the binary values and th
24–2
15 ELG–()
e resulting scaling effects of
(EQ. 16)
the AGC scaling mantissa and exponent. The composite (shifter and multiplier) AGC scaling Gain range is from
0.0000 to 2.329(0.9375)
0
2
= 0.0000 to 2.18344. The scaled
gain error can range (depending on threshold) from 0 to
2.18344, which maps to a “gain change per sample” range of 0 to 3.275dB/sample.
The AGC Gain mantissa and exponent values are prog
rammed into Control Word 8, Bits 0-15. The PDC provides for the storing of two values of AGC Scaling Gain (both exponent and mantissa). This allows for quick adjustment of the loop gain by simply asserting the external control line AGCGNSEL. When AGCGNSEL = 0, then AGC GAIN 0 is selected, and when AGCGNSEL = 1, AGC Loop Gain 1 is selected. Possible applications include acquisition/tracking, no burst present/burst present, strong signal/weak signal, track/hold, or fast/slow AGC values.
The AGC loop filter consists of an accumulator with a built in limiting function. The
maximum and minimum AGC gain limits are provided to keep the gain within a specified range and are programed by 12-bit Control Words using Equation 17:
AG
C Gain Limit 1 m
AGC Gain Limit()dB = 6.02()eeee()20 1.0 0.mmmmmmmm+()log+
+()2
=
AGC
2
e
(EQ. 17)
(EQ. 17A)
9–
where m is an 8-bit mantissa value between 0 and 255, and e is the 4-bit expon
ent ranging from 0 to 15. Control Word 9, Bits 16-27 are used for programmin g the upper limit, while bits 0-11 are used to program the lower threshold. The range s and format for these limit values are shown in Tables 6A through 6C. The bit weightings for the AGC Loop Feedback elements are detailed in Table 9A.
TABLE 6A. AGC LIMIT EXPONENT vs GAIN
GAIN(dB) EXPONENT MANTISSA
96.332 15 255
90.309 15 0
84.288 14 0
78.268 13 0
72.247 12 0
66.227 11 0
60.206 10 0
54.185 9 0
48.165 8 0
42.144 7 0
36.124 6 0
30.103 5 0
24.082 4 0
18.062 3 0
12.041 2 0
6.021 1 0
0.000 0 0
TABLE 6B. AGC LIMIT MANTISSA vs GAIN
GAIN(dB) EXPONENT MANTISSA
6.000 0 255
5.750 0 240
5.500 0 226
5.250 0 212
5.000 0 199
4.750 0 185
4.500 0 173
4.250 0 161
4.000 0 149
3.750 0 138
3.500 0 127
3.250 0 116
3.000 0 105
2.750 0 95
2.500 0 85
2.250 0 75
2.000 0 66
1.750 0 57
1.500 0 48
1.250 0 39
1.000 0 31
0.750 0 23
0.500 0 15
0.250 0 7
0.020 0 1
22
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TABLE 6C. AGC LIMIT DATA FORMAT
CONTROL WORD 9 BIT: 27 26 25 24 23 22 21 20 19 18 17 16
FORMAT e e e e m m m m m m m m
SERIAL
OUT
μP
(11 MANTISSA
4 EXPONENT)
AGC LOOP FILTER
REGISTER
AGC
LOAD
M U X
MANTISSA =
16
01.XXXXXXXXXXXXXX
16
MSB = 0
16
REGISTER
MSB = 0
4
EXP=2
EN
20
NNNN
μP
(RANGE = -2.18344 TO 2.18344)
+
LIMITER
LIMIT
DET
UPPER LIMIT
LOWER LIMIT
LIMIT
DET
AGC ERROR SCALING
13
EXP
AGCGNSEL
EXP
LOOP GAIN 0
MAN
SHIFT
MANTISSA
4
4
AGC REGISTER 0
AGC REGISTER 1
MAGNITUDE
(RANGE = 0 TO 2.3)
(RANGE = 0 TO 1)
EXP
MAN
LOOP GAIN 1
AGC
ERROR
DETECTOR
13
Δ
(S = 0)
UNSIGNED
THRESHOLD
STT.TTTTTTTTTT
IFIR
QFIR
26
26
18
SHIFTER
18
SHIFTER
AGC MULTIPLIER/SHIFTER
LIMITER
LIMIT
DET
Controlled via microprocessor interface.
FIGURE 23. AGC BLOCK DIAGRAM
Using AGC loop gain, the AGC range, and expected error detector output, the gain adjustments per output sample for the Loop Filter Section of the Digital AGC can be given by:
AGC Slew Rate 1.5dB THRESH MA G*1.64676())×(=
M
()24–()2
LG
⎛⎞ ⎝⎠
15 ELG–()
(EQ. 18)
18
IAGC
QAGC
LIMITER
RESAMPLING
FIR FILTERS
AND
INTERPOLATING
HALFBAND
FILTERS
18
CARTESIAN
TO
POLAR
COORDINATE
CONVERTER (G = 1.64676)
The loop gain determines the growth rate of the sum in the lo
op accumulator which, in turn, determines how quickly the AGC gain traces the transfer function given in Figures 21 and 22. Since the log of the gain response is roughly linear, the loop response can be appro
ximated by multiplying the
maximum AGC gain error by the loop gain. The expected
23
FN4450.4
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range for the AGC rate is ~ 0.000106 to 3.275dB/output sample time for a threshold of 1/2 scale. See the notes at the bottom of Table 9A for calculation of the AGC response times. The maximum AGC Response is given by:
AGC Response
Input(Cart/Polar Gain)(Error Det Gain) AGC(=
Max
Loop Gain)(AGC Output Weighting)
(EQ. 19)
Since the AGC error is scaled to adjust the gain, the loop settl
es asymptotically to its final value. The loop settles to
the mean of the signal.
TABLE 7. AGC LOOP GAIN BINARY MANTISSA TO GAIN
SCALE FACTOR MAPPING
BINARY
DE
CO
(MMMM)
0000 0.0000 1000 0.5000 0001 0.0625 1001 0.5625 0010 0.1250 1010 0.6250 0011 0.1875 1011 0.6875 0100 0.2500 1100 0.7500 0101 0.3125 1101 0.8125 0110 0.3750 1110 0.8750 0111 0.4375 1111 0.9375
TABLE 8. AGC LOOP GAIN BINARY EXPONENT TO GAIN
BINARY
DE
CO
(EEEE)
0000 2 0001 2 0010 2 0011 2 0100 2 0101 2 0110 2 0111 2
SCALE
FA
CTOR
SCALE FACTOR MAPPING
SCALE
CTOR
FA
15
14
13
12
11
10-
9
8
BINARY
DE
CO
(MMMM)
BINARY
DE
CO
(EEEE)
1000 2 1001 2 1010 2 1011 2 1100 2 1101 2 1110 2
1111 2
SCALE
FA
CTOR
SCALE
CTOR
FA
7
6
5
4
3
2
1
0
when AGCGNSEL = 0, and selecting Gain 1 when AGCGNSEL = 1.
In the HSP50214, a reset event (caused by SYNCIN2 or CW
25) would clear the AGC loop filter accumulator. In the HSP50214B, if Control Word 27, Bit 15 is set to zero, the AGC loop filter accumulator will clear as in the original HSP50214. If Control Word 27, Bit 15 is set to a one, the backend reset (from CW25) will not clear the AGC loop filter accumulator.
In the HSP50214, the settling mode of the AGC forces the mean
of the signal magnitude error to zero. The gain error is scaled and used to adjust the gain up or down. This proportional scaling mode causes the AGC to settle to the final gain value asymptotically. This AGC settling mode is preferred in many applications because the loop gain adjustments get smaller and smaller as the loop settles, reducing any AM distortion caused by the AGC.
With this AGC settling mode, the proportional gain error cause
s the loop to settle more slowly if the threshold is small. This is because the maximum value of the threshold minus the magnitude is smaller. Also, the settling can be asymmetric, where the loop may settle faster for “over range” signals than for “under range” signals (or vice versa).
In some applications, such as burst signals or TDMA signals, a very fast settli
ng time and/or a more predictable settling time is desired. The AGC may be turned off or slowed down after an initial AGC settling period.
To minimize the settling time, a median AGC settling mode ha
s been added to the HSP50214B. This mode uses a fixed gain adjustment with only the direction of the adjustment controlled by the gain error. This makes the settling time independent of the signal level.
For example, if the loop is set to adj
ust 0.5dB per output sample, the loop gain can slew up or down by 16dB in 16 symbol times, assuming a 2 samples per symbol output sample rate. This is called a median settling mode because the loop settles to where there is an equal number of magnitude samples above and below the threshold. The disadvantage of this mode is that the loop will have a wander (dither) equal to the programmed step size. For this reason, it is advisable to set one loop gain for fast settling at the beginning of the burst and the second loop gain for small adjustments during tracking.
For example, if MLG = 0101 and ELG = 1100 , the AGC Loop Gain = 0.3125*2
-7
. The loop gain mantissas and exponents are set in the AGC Loop Parameter Control Register (Control Word 8, Bits 0-15).
Two AGC loop gains a re provided in the Programmable Dow n C
onverter, for quick adjustment of the AGC loop. The AGC
Gain select is a control input to the device, selecting Gain 0
The median settling mode is enabled by setting Control W
ord 27, Bit 16 to a logic one. If Control Word 27, Bit 16 is zero, the mean loop settling mode is selected and the loop works identically to the HSP50214.
In the median mode, the loop works as follows: The sign of the true gain error selects a fixed gain error of
00
10000000000
24
or 1110000000000b.
b
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These gain error values are scaled by the programmable AGC loop gains to adjust the data path gain.
The maximum slew rate is ~1.5dB per output sample. See Equa
tion 18.
In order to fully evaluate the dynamic range of the PDC, T
able 9B is provided, which details the bit weighting from the
input to the AGC Multiplier.
Re-Sampler/Halfband Filter
The re-sampler is an NCO controlled polyphase filter that allows the output sample rate to have a non-integer relationship to the input sa mple rate. The f ilter engine can be viewed conceptually as a fixed interpolation filter, followed by an NCO controlled decimator.
The prototype polyphase filter has 192 times the input sample rate. Each of the 32 phases has 6 filter taps (6)(32) = 192. The stopband attenuation of the prototype filter is greater than 60dB, as shown in Figure 24. The signal to total image power ratio is approximately 55dB, due
to the aliasing of the interpolation images. The filter is capable of decimation factors from 1 to 4. If the output is at least 2x the baud rate, the 32 interpolation phases yield an effective sample rate of 64x the baud rate or approximately
1.5%, (1/64), maximum timing error. Following the Re-sampler are two interpolation halfband
fi
lters. The halfband filters allow the user to up-sample by 2 or 4 to recover time resolution lost by decimating. Interpolating by 2 or 4 gives 1/4 or 1/8 baud time resolution (assuming 2x baud at the re-sampler output). The halfband filters use the same coefficients as HB3 and HB5 from the Halfband Filters Section. If one halfband is used, the 23-tap filter is chosen. If two are used, the 23-tap filter runs first
taps designed at 32
followed by the 15-tap filter operating at twice the first halfband’s rate. The 23-tap filter requires 7 multiplies, and the 15-tap filter requires 5 multiplies to complete a filter calculation.
Using the interpolation halfband filters allows for reduction in the FIR fi
lter sample rate. This optimizes the use of the programmable FIR filter by allowing the FIR output sample rate to be closer to the Nyquist rate of the desired bandwidth. Optimizing the FIR filter performance provides better use of the programmable FIR taps. Table 10 details the maximum clocking rates for the possible resampling and interpolation ha
lfband filter configurations of this section of the PDC. Control Word 16, Bits 2-0 identify the filter configuration. Control Word 16, Bit 3 is used to by pass the polyphase re­sampler filter.
For proper data output from the inte
rpolation filters, the data ready signal must account for the interpolation process. Figure 25 illustrates the insertion of additional data ready pulses to provide sufficient pulses for the new output sample rate.
The Re-sampler Output Pulse Delay parameter is set in Control Word 16, Bits 4-1 1. These bits set the delay between the output samples when interpolation is utilized. Program this distance between pulses using
()1][=
Nf
PROCCLK/fOUT
(EQ. 20)
A value of at least 5 is required to have sufficient time to upd
ate the Output Buffer Register. (Writing 5 samples requires 5 clock cycles) A value of at least 16 is required for proper serial output from the part. (Conversion from 16-bit parallel to serial). The value is programmed in numbers of PROCCLK’s.
0
-20
-40
-60
MAGNITUDE (dB)
-80
-100
-120 12345678910111213141516
FREQUENCY (RELATIVE TO f
FIGURE 24A. POL YPHASE RESAMPLER FIL TER BROADBAND
FREQUENCY RESPONSE
There is a 65dB limitation in SNR using the R
)
S
e-Sampler Filter. When only the Interpolation FIRs are used, the full SNR range is passed.
25
FIGURE 24.
10
0
-10
-20
-30
-40
-50
MAGNITUDE (dB)
-60
-70
-80 0
0.0625
FIGURE 24B. POLYPHASE RESAMPLER FILTER P ASS BAND
0.25
0.125
0.1875
0.3125
FREQUENCY (RELATIVE T O fS)
FREQUENCY RESPONSE
0.5
0.375
0.4375
0.5625
0.75
0.625
0.6875
0.875
0.8125
FN4450.4
May 1, 2007
0.9375
1
HSP50214B
www.BDTIC.com/Intersil
.
AGC
ACCUM
POSITION
BIT
GAIN
RROR
E
INPUT
GAIN
RROR
E
BIT
WEIGHT
TABLE 9A. BIT WEIGHTING FOR AGC LOOP FEEDBACK PATH
AGC LOOP
TER
AGC LOOP
ILTER GAIN
F
(MANTISSA)
FIL
GAIN
MULTIPLIER
(OUTPUT)
SHIFT
= 0
SHIFT
= 4
SHIFT
= 8
SHIFT
= 15
AGC
TPUT
OU
AND AGC
LIMITS BIT
WEIGHT
31 2 2 2 2 0 30 2 2 2
2 E 3 48 29 2 2 2 2 E 2 24 28 2 2 2 27 12 = 2 2 2 2 2
2 E 1 12
2 E 0 6 26 11 = 1 1 2 2 2 1 M -1 3
25 10 = 0. 0. 0. 2 2 2 24 9 = 1 x 1 2 2 2 23 8 = 2 x 2 2 2 2 22 7 = 3 x 3 2 2 2 21 6 = 4 x 4 2 2 2
0. M -2 1.5 1 M -3 0.75 2 M -4 0.375 3 M -5 0.1875 4 M -6 0.09375
20 5 = 5 5 2 2 2 5 M -7 0.04688 19 4 = 6 6 2 2 1 18 3 = 7 7 2 2 0.
6 X -8 0.02344 7 -9 0.01172
17 2 = 8 8 2 2 1 8 -10 0.00586 16 1 = 9 9 2 2 2
9 -11 0.00293
15 0 = 10 10 2 1 3 10 -12 0.00146 14 11 2 0. 4 11 -13 0.000732 13 12 2 1 5 12 -14 0.000366 12 13 2 2 6 13 -15 0.000183 11 14 1 3 7 14 -16 0.0000916 10 0. 4 8 G -17 0.0000458
9 1 5 9 G -18 0.0000229 8 2 6 10 G -19 0.0000114 7 3 7 11 G -20 0.00000572 6 4 8 12 G -21 0.00000286 5 5 9 13 G 4 6 10 14 G 3 7 11 G G 2 8 12 G G 1 9 13 G G 0 10 14 G G
AGC Response
AGC Response
= Input(Cart/PolarGain)(Error Det Gain)(AGC Loop Gain
Max
15
⎛⎞
= .
Max
2()1.64676()
------
⎝⎠
16
1()1.5dB()3.275dB/output sample time
)(AGC Output Weighting).G = ground = 0.
Max
AGC GAIN
OLUTION
RES
(dB)
AGC Response
2()1.64676()2
= .
Min
15
()1()1.5dB()0.000106dB/output sample time
Thus, the expected range for the AGC rate is ~ 0.000106 to 3.275dB/output sample time.
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TABLE 9B. PDC BIT WEIGHTING
BIT
WEIGHT INPUT SIN/COS MIX OUT
0 0 0 0 S S xxxxxxxxxx 0 0 0 0 1 1 1 1 1 S S xxxxxxxxxx 1 1 1 1 0 0 2 2 2 2 S S xxxxxxxxxx 2 2 2 2 1 1 3 3 3 3 S S xxxxxxxxxx 3 3 3 3 2 2 4 4 4 4 S S xxxxxxxxxx 4 4 4 4 3 3 5 5 5 5 S S xxxxxxxxxx 5 5 5 5 4 4 6 6 6 6 S S xxxxxxxxxx 6 6 6 6 5 5 7 7 7 7 S S xxxxxxxxxx 7 7 7 7 6 6 8 8 8 8 S S xxxxxxxxxx 8 8 8 8 7 7
9 10 10 10 10 S 10(S) xxxxxxxxxx 10 10 10 10 9 9 11 11 11 11 S 11 xxxxxxxxxx 11 11 11 11 10 10 12 12 12 12 S 12 xxxxxxxxxx 12 12 12 12 11 11 13 13 13 13 S 13 xxxxxxxxxx 13 13 13 13 12 12 14 14 14 S 14 xxxxxxxxxx 14 14 14 14 13 13 15 15 SRnd S 15 xxxxxxxxxx 15 15 15 15 14 14 16 16 S 16 xxxxxxxxxx 16 16 16 16 15 15 17 17 S 17 xxxxxxxxxx 17 17 17 17 16 16 18 S 18 xxxxxxxxxx 18 18 18 18 17 17 19 S 19 xxxxxxxxxx 19 19 19 19 18 18 20 S 20 xxxxxxxxxx 21 S 21 xxxxxxxxxx 21 21 21 21 20 20 22 S 22 xxxxxxxxxx 22 22 22 21 21 23 S 23 xxxxxxxxxx 23 23 23 22 22 24 S 24 xxxxx Rnd Rnd Rnd 23 23 25 25(S) 25 xxxxx SAT SAT SAT 24 24 26 26 26 xxxxx 25 Rnd 27 27 27 xxxxx 26 SAT 28 28 28 xxxxx 27 29 29 29 xxxxx 28 30 30 30 xxxxx 29 31 31 31 xxxxx 30 32 32 32 xx 31 33 33 33 xx 32 34 34 34 xx (Rnd Out
35 35 35 xx 36 36 36 x 37 37 37 x 38 38 38 x 39 39 39 x
NOTES:
1. SRnd = Symmetric Round; Rnd = Round; SAT = Saturation.
2. The NBW out of the CIC filter is 0.5 x f should be ~ 8 (9dB or 1.5 bits) versus A/D noise, the processing gain should be 10log(BW
9 9 9 S S xxxxxxxxxx 9 9 9 9 8 8
CIC IN
SHIFT = 0
. If the NBWIN = fS / 4 and NBWOUT = f
SOUT
CIC IN
SHIFT = 15
CIC BIT
W
EIGHTS
IIIIICCCCC CIC OUT HB DAT A IN
20 20 20 20 19 19
/2, then the processing gain for a decimation x 16 CIC
SOUT
IN
/ BW
OUT
HB DATA
OUT/FIR
).
IN
FIR
COEF
FIR
MU
LTI/
ACC
of Mult.)
FIR
OUT
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2 1 0
-1
-2
-3
-4
-5
-6
MAGNITUDE (dB)
-7
-8
-9
-10 0
0.125
0.0625 FREQUENCY (RELATIVE TO fS)
0.1875
0.25
0.3125
0.375
0.4375
FIGURE 24C. POLYPHASE RESAMPLER FIL TER EXP ANDED
RESOLUTION PASSBAND FREQUENCY RESPONSE
TABLE 10. POLYPHASE AND INTERPOLATING HALFBAND
FILTER MAXIMUM CLOCKING RATES
RE-SAMPLER
PUT
MODE
CLOCK
CYCLES
IN
RATE (MHz)
INTER-
POLATION
RATE
OUTPUT
RATE (MHz)
Bypass 0 55.00 - 55.00 Polyphase Filter 6 55/6 = 9.17 - 9.17
(Note 3)
Polyphase and 1 Halfband
13 55/13 = 4.23 2 8.46
(Note 3)
Filter Polyphase and
2 Halfband
23 55/23 = 2.39 4 9.56
(Note 3)
Filters 1 Halfband
7 55/7 = 7.86 2 15.72
Filter 2 Halfband
17 55/17 = 3.24 4 12.94
Filters
NOTE:
3. This frequency is set by the Resampler NCO.
In burst systems (such as TDMA), time resolution is needed for quickly identifying the optimum sample point. The timing is adjusted by shifting the decimati o n i n th e DSP μP to the closest sample. Use of timing error in this way may yield a faster acquisition than a phase-locked loop coherent bit synchronization. Finding the optimum sample point minimizes intersymbol interference.
Fine time resolution is needed in CDMA systems to resolve di
fferent multipath rays. In CDMA systems, the demands on the programmable FIR can only be relieved by the resampler/interpolation halfband filters. Assume the chip rate for a baseband CDMA system is 1.2288MHz and PROCCLK
0.5
is limited to 55MHz. Using the symmetric filter pre-sum approach, PROCCLK limits the programmable FIR to 11 0MIPS (millions of instructions per se cond) effective due to symmetry . If the CDMA filter (loaded into the programmabl e FIR Section) requires an impulse response with a span of 12 chips, the filter at 2x the chip-rate would need 24 tap s. The 24 taps would translate into 59MIPS = (1.2288MHz)(2)(24). To get the same filtering at 8x the chip rate would require 944MIPS = (1.2288MHz)(8)(96). Direct 8x filtering can not be accomplished with the programmable filter alone because 944MIPS are much greater that the 60MIPs effective limit set by PROCCLK. It is necessary to decimate down to 2x the chip rate to get a realistic number of filter taps. Both interpolation halfband filters are then used to obtain the 8x CDMA output. 944MIPS is a lot of MIPS. The HSP50214B gets the equivalent processing by decimating down and interpolating backup.
POLYPHASE
RESAMPLER
FILTER
RESAMPLER
NCO
PROCCLK
PROCCLK/N
THIS BLOCK GENERATES EXTRA DATA READY PULSES FOR THE NEW OUTPUTS FROM THE INTERPOLATION PROCESS.
NV = INVALID MODE
HALFBAND
FILTER #1
PULSE DELAY
COUNTER
FIGURE 25. GENERATING DA TA READY PULSES FOR
OUTPUT DATA
PULSE DELAY
HALFBAND
FILTER #2
HB2
HB1
0
00
1
0
0
0
1
0
1
1
0
0
1
0
0
1
1
1
1
0
1
1
1
MUX
# EXTRA PULSES
RSMPLR
0 BYPASS 0 1 1
(
3
3 (NV) 3
3
)
V
N
Timing NCO
The Timing NCO is very similar to the carrier NCO Phase Accumulator Section. It provides the NCO driven sample pulse and associated phase information to the resampling filter process described in the Re-sampler Filter Section. The Timing NCO does not include the SIN/COS Section found in the Carrier NCO. The top level block diagram is shown in Figure 26.
28
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EN EXT TIMING NCO SYNC
SYNCIN2 TIMING PHASE STROBE
TIMING NCO
PHASE OFFSET
SYNC
REG
PHASE
ACCUMULATOR
REG
FILTER PHASE SELECT
5
8
REG
+
CARRY OUT = RUN FILTER STROBE
CLEAR PHASE
0
MUX
ACC
+
TIMING NCO
PH ACC
LOAD ON UPDATE
TIMING FREQ STROBE
SOF
SOF
SYNC
SHIFT REG
ENABLE SOF
SOFSYNC
NUMBER OF SOF BITS
MUX
32
0
REG
TIMING NCO CENTER
32
SCF
REG REG
FREQUENCY
SYNC
Controlled via microprocessor interface.
FIGURE 26. TIMING NCO BLOCK DIAGRAM
The programmable parameters for the Timing NCO include an Enable External Timing NCO Sync (Control Word 11, Bit
5), the serial word width, Number of Offset Frequency Bits (Control Word 11, Bits 3-4), an Enable Offset Frequency control (Control Word 11, Bit 2), a Clear NCO Accumulator control (Control Word 11, Bit 1), a Timing NCO Phase Accumulator Load On Update control (Control Word 11, Bit
0), the Timing NCO Center Frequency (Control Word 12), a Timing Phase Offset (Control Word 13, Bits 0-7), a Timing Frequency Strobe (Control Word 14) and a Timing Phase Strobe (Control Word 15). Refer to the Carrier Synthesizer Mixer Section for a detailed discussion of the serial interface for the Timing NCO offset frequency word.
A timing error detector is provided for measuring the phase di
fference between the timing NCO and a external clock input, REFCLK. Timing Error is generated by comparing the values of two programmable counters. One counter is clocked with the Timing NCO carry out and the other is clocked by the REFCLK. The 12-bit NCO Divide parameter is set in Control Word 18, Bits 16-27. The NCO Divide parameter is the preload to the counter that is clocked by the Timing NC O carry out. The 12-bit Reference Divide parameter is set in Control Word 18, Bits 0-11, and is the preload for the counter that is clocked by the Reference clock. Figure 26 details the block diagram of the timing error generation circui
t. The 16-bits of timing error are available both as a PDC serial output and as a processor read parameter. See the Processor Read Sectio n for more details on accessing this value.
TIMING
NCO
ACC.
CARRY
PHASE(31:28)
REFCLK
NCO DIVIDE
PROGRAMMABLE
DIVIDER
REFERENCE
DIVIDE
PROGRAMMABLE
DIVIDER
(NCO DIVIDE)/2
-
12
+
4
REG
EN
Δ
TE(15:0)
Controlled via microprocessor interface.
FIGURE 27. TIMING ERROR GENERATION
Figure 27A illustrates an application where the Timing Error Generator is used to lock the receiver samples with a tra
nsmit data rate. In this example, the receive samples are at four times the transmit data rate. An external loop filter is required, whose frequency error output is fed into the Timing NCO. This allows the loop to track out the long term drift between the receive sample rate and the transmit data clock.
LOOP
FILTER
μP
TIMING
NCO
ACC.
CARRY
PHASE(31:28)
Tx DATA CLK
(REFCLK)
RT = TOTAL DECIMATION (CIC, HB FILTERS AND FIR)
CLKIN/R
T
NCO DIVIDE = 4N
PROGRAMMABLE
DIVIDER
REFERENCE
DIVIDE = N
PROGRAMMABLE
DIVIDER
(NCO DIVIDE)/2
-
12
+
4
REG
EN
TO Tx BLOCK (MODULATOR)
Δ
TE(15:0)
Controlled via microprocessor interface.
FIGURE 27A. TIMING ERROR APPLICATION
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Cartesian to Polar Converter
The Cartesian to Polar converter computes the magnitude and phase of the I/Q vector. The I and Q inputs are 18 bits. Th
e converter phase output is 18-bits (truncated) with the 16 MSB’s routed to the output formatter and all 18-bits routed to the frequency discriminator. The 16-bit output phase can be interpreted either as two’s complement (-0.5 to approximately 0.5) or unsigned (0.0 to approximately 1.0), as shown in Figure 28. The phase conversion gain is 1/2π. The phase resolution is 16-bits. The 16-bit magnitude is unsi
gned binary format with a range from 0 to 2.32. The magnitude conversion gain is 1.64676. The magnitude resolution is 16 bits. The MSB is always zero.
Table 11 details the phase and magn 16-bits output from the PDC.
TABLE 11. MAG/PHASE BIT WEIGHTING
BIT MAGNITUDE PHASE (
2
15 (MSB) 2
14 2 13 2 12 2 11 2 10 2
9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2
0 (LSB) 2
(Always 0) 180
itude weighting for the
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-11
-12
-13
90 45
22.5
11.25
5.625
2.8125
1.40625
0.703125
0.3515625
0.17578125
0.087890625
0.043945312
0.021972656
0.010986328
0.005483164
o
)
The magnitude and phase computation requires 17 clocks for
full precision. At the end of the 17 clocks, the magnitude and phase are latched into a register to be held for the next stage, either the output formatter or frequency discriminator. If a new input sample arrives before the end of the 17 cycles, the results of the computations up until that time, are latched. This latching means that an increase in speed causes only a decrease in resolution. Table 12 details the exact resolution that can be obtained with a fixed number of clock cycles up
to the required 17. The input magnitude and phase errors induced by normal SNR values will almost always be worse than the Cartesian to Polar conversion.
TABLE 12. MAG/PHASE ACCURACY vs CLOCK CYCLES
MAGNITUDE
ERROR
CLOCKS
6 0.065 3.5 2 7 0.016 1.8 1 8 0.004 0.9 0.5
9 <0.004 0.45 0.25 10 <0.004 0.22 0.12 11 <0.004 0.11 0.062 12 <0.004 0.056 0.03 13 <0.004 0.028 0.016 14 <0.004 0.014 0.008 15 <0.004 0.007 0.004 16 <0.004 0.0035 0.002 17 <0.004 0.00175 0.001
Assumes ±180
o
= fS.
(% f
)
S
PHASE
ERROR
(DEG.)
PHASE
ERROR
(% f
S
)
In the HSP50214, the input to the coordinate converter I/Q to |r|/θ) bl
ock is 18-bits. If the signal range is large and the AGC
is not used, the quantization noise can become a contributing factor in the phase and frequency computations. For example, if the signal range is 84dB and the maximum signal is set at full scale, the minimum signal would have only 4-bits each for I and Q.
In the HSP50214B, an additional data path option was ad
ded that allows the output of the 255 tap programmable FIR filter to be routed directly to the coordinate converter. Rather than having to select only 18-bits out of the available 26 bit output, all 26-bits of the FIR output are routed to the coordinate converter. This change eliminates quantization effects to give more accuracy in the phase and frequency discriminator outputs. The AGC settling time is not a factor because the AGC is effectively bypassed for the magnitude, phase, and frequency computations.
NOTE: The most significant 18-bits of the computed phase are
still routed to the discriminator.
+π/2
3ff f
4000
Q
7fff
±π
8000
bfff
-π/2
FIGURE 28. PHASE BIT MAPPING OF COORDINATE
CONVERTER OUTPUT
c000
I
0000
0
ffff
7fff
π
8000
4000
bfff
π/2
3π/2
3fff
Q
c000
I
0000
0
ffff
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One caveat to selecting the FIR outputs to be routed directly to the coordinate converter is that because the I/Q samples for the coordinate conversion are chosen from before the resampler, the magnitude and phase samples will not align with the I/Q samples, if the resampler or interpolation halfband filters are used.
This optional signal routing mode was intended for FM or for burst PSK
where a fixed decimation can be used. It is also applicable when resampling or timing adjustments on the demodulated samples are done in a processor following PDC.
The magnitude resolution may suffer because there is no gai
n adjustment before computing the magnitude. If the signal is < - 90dBFS, it will be below the LSB of the magnitude output.
The enable signal for gating data into the coordinate converter is either the AGC da
ta ready signal or the resampler data ready signal. If the resampler is bypassed, the AGC data ready signal is used and there is a delay of 6 clock cycles between the FIR data being ready and the coordinate converter block sampling it. If the resampler is enabled, its data ready signal will be delayed by 6 clocks (for the AGC) plus the compute delay of the resampler block. This may cause the I/Q to |r|/θ output sample alignment to shift with decimation. For this reason, it is recommended that the resampler/halfband filter block be bypassed when using this new data path.
T o select the output of the 255 tap programmable FIR filter to be routed
to the coordinate converter, set Control Word 27, Bit 13 to a logic one. For routing as in the HSP50214, set Control Word 27, Bit 13 to a logic zero.
Frequency Discriminator
The discriminator block delays phase from the Cartesian to Polar Section and subtracts it from the latest sample. This delay and subtract can be modeled as a programmable delay comb filter. The output of the filter is dθ/dt, or frequency. The transfer function of the discriminator is set by
Hz() 1Z
where D is the programmable discrimin in number of sample clock delays. The discriminator output frequency is then filtered with a programmable FIR filter. The Block Diagram of the Frequency Discriminator is shown in Figure 29.
The range of delay in the discriminator is from 1 to 8 sample in the subtraction at 2π. The alias free discriminator frequency range is given by:
Rang
D–
=
(EQ. 21)
ator delay expressed
s. Modulo 2π subtraction eliminates rollover problems
e
FREQDISC
CW F±
SAMPOUT
D1+() ;=
(EQ. 22)
where D is the discriminator delay defined in Equation 21 (1 < D < 8), f
SAMPOUT
is the Discriminator FIR filter output sample rate and CW is the desired center frequency. When the phase multiplier is set to a value other than 2
0
, the discriminator range is reduced proportionally. The phase multiplier can be 1, 2, 4 or 8 (2 reduces the range by 2, a multiply of 2 by 4, and a multiply of 2
The FIR filter can be configured wi
0
to 23). Thus, a multiply of 21
2
3
reduces the range by 8.
reduces the range
th up to 63 symmetric taps and up to 32 asymmetric taps. In the symmetric mode, the FIR can be configured for even or odd symmetry, as well as with an even or odd number of filter taps. Decimation is provided to allow more processing time for longer (i.e., more taps) filter structures.
PHASE INPUT
PHASE MULTIPLIER
DISCRIMINATOR DELAY
DISCRIMINATOR EN
FIR COEFFICIENTS
DISC. FIR DECIMATION
FIR SYMMETRY TYPE
FIR SYMMETRY
FIR TAPS
DELAY
(1-8)
-
+
+
63-TAP
FIR
FILTER
FREQ(15:0) (2’s COMPLEMENT)
Controlled via microprocessor interface.
FIGURE 29. FREQUENCY DISCRIMINATOR BLOCK DIAGRAM
The HSP50214B offers an expanded choice of signals to be filtered
by the discriminator FIR. The choices are:
1) 18-bits of delayed, and subtra
cted (and optionally shifted) phase. This is the Discriminator FIR filter input found in the HSP50214.
2) 18-bits of magnitude from the
coordinate converter block. This was added to provide for post-detection filtering of AM signals.
3) 18-bits from the I output of the resampler/interpolation ha
lfband filter block. This was added to provide for
processing of SSB signals. The shift, delay, and subtract functions are bypassed for
items (2) and
(3).
In addition to the FIR input selections, the Q input to the coord
inate converter block can be zeroed so that the magnitude output is the magnitude of I only. Again this was added to provide for processing SSB signals.
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The Discriminator FIR filter input selections are made in Control Word 27, Bits 18 and 19. The bit definitions are:
00 Item (1) described above. 01 Item (2) described above. 1X Item (3) described above. Control Word 27, Bit 14 is used to control the Q input to the
coordi
nate converter. The bit definitions is:
0 I and Q enabled to the I/Q to R/Theta block. 1 The Q input to the I/Q to R/Theta block is zeroed.
The enable signals associated with the various input
ctions to the Discriminator FIR filter are:
sele
1 The data ready strobe from the coordinate con-
verter block.
2 The data ready strobe from the coordinate con-
verter block.
The enable signals associated with the various input
ctions to the coordinate converter are:
sele
3a The data ready signal to the coordinate converter
block
when the resampler is bypassed. This is the
AGC output data ready signal.
3b The data ready to the coordinate converter block
the resampler/halfband filters are enabled.
when This is the resampler halfband filter block output data ready signal.
The discriminator input is 18-bits, and the output is rounded asymme can be multiplied by 2
trically to 16-bits. The phase into the discriminator
0
, 21, 22, or 23 (modulo 2π) to remove PSK data modulation. All programmable parameters for the Frequency Discriminator are set in Control Word 17. Bits 15 and 16 are the phase multiplier which represents the shift applied to the input phase. For CW, the multiply should equal
0
2
, (00). For BPSK, QPSK, and 8PSK, the multiply should
1
equal 2
, (01); 22, (10); or 23, (11); respectively. Bit 14 is used to enable or disable the discriminator. Bits 1 1-13 set the decimation in the programmable FIR filter. Bit 10 sets the filter symmetry type as either odd or even, bit 9 sets whether the filter is asymmetric or symmetric, and bits 3-8 set the number of FIR filter taps. Bits 0-2 set the nu mber of del ays in the frequency discriminator.
Output Section
The Output Section routes the 7 types of processed signals to output pins in three basic modes. These basic modes are: Parallel Direct Output, Serial Direct Output, and the Buf fer RAM Output. The Serial and Parallel Direct Output modes were designed to output data strobes and “real time” continuous streams of data. The Buffer RAM Output mode outputs data upon receipt of an asynchronous request from an external DSP processor or other baseband processing engine. The use of the interrupt signal from the Programmable Down Converter in conjunction with the
request strobes from the controller ensures that data is transferred only when both the controller and the Programmable Down Converter are ready. The Buff e r RA M output can be operated in a First In First Out (FIFO) or SNAPSHOT mode with the data output either via the 8-bit processor interface or a 16-bit processor interface.
Parallel Direct Output Port Mode
The Parallel Direct Output Port Mode outputs two 16-bit words, AOUT and BOUT, of “real time” data. Figure 30 details the parallel output circuitry . Selection of the data source for the AOU
T and BOUT parallel outputs is done via Control Word 20, Bits 22-23, and 20-21, respectively. The AOUT port can output I, Magnitude, or Frequency data. The BOUT port can output Q, Phase or Magnitude data. The upper bytes of AOUT and BOUT are always in the parallel direct mode. The 16-bit parallel direct mode is selected by setting Control Word 20, Bit 25, to zero.
The
DATARDY output is asserted during the first clock cycle of the new data on the AOUT bus. The rate at which the data out of the HSP50214 transitions and the rate at which DATARDY is asserted can be different.
Data Transitions:
The transition rate of the parallel output data is dependent on which of the three types of data is selected for the AOUT Output channel: I (real symbols), |r| (magnitude), or f (frequency). Q (quadrature symbols), ø (phase), or |r| (magnitude) are available on the BOUT output. When selected as an output, the I Q, |r|, and ø outputs transition at the symbol rate. The f (frequency) output transitions at the discriminator FIR filter output rate.
AOUT DIRECT PAR OUTPUT MODE DATA SOURCE
(2’s COMPLEMENT)
(UNSIGNED BINARY)
(2’s COMPLEMENT)
(2’s COMPLEMENT)
(2’s COMPLEMENT)
(UNSIGNED BINARY)
Controlled via microprocessor interface.
MAG
FREQ
BOUT DIRECT PAR OUTPUT MODE DATA SOURCE
PHAS
MAG
RAM (15:0)
DATA SOURCE FOR LSB
FIGURE 30. PARALLEL OUTPUT BLOCK DIAGRAM
MUX
DATARDY
AOUT(15:8)
AOUT(7:0)
16
I
16
MUXMUX
16
A(15:8) A(7:0)
RAM(15:8)
16
Q
16
16
B(15:8) B(7:0)
RAM (7:0)
MUX
BOUT(15:8)
BOUT(7:0)
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Data Ready Signal Assertion Rate:
The assertion rate of the DATARDY signal Is the data transition rate of the A time alignment of parallel data words available for output are as follows:
output data either [I, |r| or f]. The
OUT
time with respect to
DA TARDY, depending on the type of data selected for output. This is because of the timing relationships defined above, and because the DATARDY is driven by the AOUT signal. Figure 32 details such a configuration.
• I and Q are aligned in time,
• |r| and ø are time aligned, but one sample clock delayed fro
m the associated I and Q samples.
DATARDY Is asserted time aligned with and at the same
as the data type selected for the AOUT output.
rate
Figure 31 details the timing of the AOUT and
DATARDY for
an AOUT = I data selection.
When the f (frequency) word is selected for output on AOUT, the DA
TARDY signal is asserted at the discriminator FIR filter output rate, which will be a reduced rate when decimation is engaged in the filter. The f (frequency)S output is delayed from the associated I and Q samples one sample time plus, the discriminator FIR filter impulse response time. Figure 33 details the timing of this configuration for a FIR filter that decimates by 4.
AOUT
PROCCLK
DATARDY
NOTE: The number of PROCCLKS per output symbol is not representative, but shown to be small for clarity of establishing timing with respect to the DATARDY signal. For each application, the relationship of the exact nature of the timing.
I0 I1 I2 I3 I4 I5 I6
DR
0 DR1 DR2 DR3 DR4 DR5 DR6
output symbol rate to PROCCLK must be properly illustrated to determine the
FIGURE 31.
DATARDY WAVEFORMS WHEN I (READ DATA) IS SELECTED AS AOUT
BOUT
AOUT
PROCCLK
DATARDY
BOUT
AOUT
PROCCLK
DATARDY
NOTE: I and Q are sample aligned in time. |r| and
is delayed in time from I or Q by 1 sample time + 63 tap FIR impulse response. If the FIR is set to decimate and frequency is selected for AOUT, the DATARDY signal will be at the discriminator FIR output (decimated) rate.
Q0 Q1 Q2 Q3 Q4 Q5 Q6
|r|0 |r|1 |r|2 |r|3 |r|4 |r|5 |r|6
DR
0 DR1 DR2 DR3 DR4 DR5 DR6
FIGURE 32. DATARDY WAVEFORMS WHEN |r| (MAGNITUDE) IS SELECTED AS AOUT
1 + FIR Delay
Q0 Q1 Q2 Q3 Q4 Qn Qn+1 Qn+2
DR-1
φ are sample aligned in time, but one sample delayed from I or Q. The frequency sample
FIGURE 33. DATARDY WAVEFORMS WHEN f (FREQUENCY) IS SELECTED AS AOUT
DR
0
f0 (R = 4)
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Serial Direct Output Port Mode
The Serial Direct Output Port Mode offers the ability to construct two serial output data streams, SEROUT A AND SEROUTB, from 16-bit I, Q, magnitude, phase, frequency, timing error, and AGC level data words. The total number of data words (1 to 8) for serial output, and the sequential order of these data word components of the serial output are programmable. Each data word may be used once in either the SEROUTA or SEROUTB dat a streams. Figure 34 illustrates the conceptual implementation of the Mode.
In the Serial Direct Mode, the output data is loaded into Serial Shif
t Registers and routed to two serial output pins, SEROUTA and SEROUTB. The serial output shift clock, SERCLK, is PROCCLK divided by 1, 2, 4, 8, or 16. The divide down ratio is programmed using Control Word 20, Bits 14-16. The data is shifted out on the rising edge of the internal SERCLK . The external clock polarity of SERCL programmable via Control Word 20, Bit 18. A sync signal is provided for detection of the start or end of each word in the serial sequence. Control Word 20, Bit 17, sets the SERSYNC signal location as either preceding the MSB (typical for interfacing with microprocessors) or following the LSB (typical for interfacing to D/A converters). Control Word 20, Bit 19, sets the SERSYNC polarity as active low or high. The LSB of each data word can be configured as either the true LSB data, or set at a fixed logic “1” or “0” for use as a tag bit. Control Word 20, Bits 0-13 set the LSB of each of the 7 types of data words that can be configured in the serial output stream. Control Word 19, Bits 21-24 set the number of serial data words that will be linked to form the serial outputs. Up to 7 data words can be linked to fo rm the serial output. SEROUTA and SEROUTB will have an identical number of words in the serial output streams.
The 16-bit I, Q, magnitude, phase, frequency, timing error, AGC le
vel, and “zeros” data words are loaded into their respective shift registers. The Magnitude and AGC Level data word are unsigned binary format with a leading zero, while the remaining signals are 2’s complement format.
Any of the eight data sources can be s ele ct ed a s the f ir st se
rial word for SEROUTA or SEROUTB. Control Word 19, Bits 25-30 set the data type for the first serial word for SEROUTA and SEROUTB. The three bit data type identifier is shown both in Table 13 and in Figure 34, to the right of the controls for the cross matrix switch. Serial ou
tput data word sequences are formed by linking data words by programming the data source for each shift requester’s shift input signal. This programming links the Shift Registers together in one or two serial chains. Thus, the Control Word 19 term “Link follows X data”, where X is one of the seven data types. Once the data source data word is selected (by programming a three bit word representing one of the data types into Control Word 19, Bits 25-27 (SEROUTA), and 28-30 (SEROUTB)), the
Serial Direct Output Port
K is
process for identifying the next word is to select a three bit data type identifier which represents the data type to fol low the source data type. Program these bits into the Control Word 19 field representing the “Link following X data”, where X = the source data type, defines the second word in the sequence. Likewise, the third data word is linked by selecting the Control Word 19-bits that identify the “Link following X data”, where X = the data type of the second word in the serial chain. The process continues until all the desired data words have been linked.
NOTE: I and Q are sample aligned in time. |r| and φ are sample
aligned in time, but one sample delayed from I or Q. The frequency sample is delayed in time from I or Q by 1 sample time + 63 tap FIR impulse response. If the FIR is set to decimate, the FIR output will be repeated every sample time until a new value appears at the filter output. (i.e., the frequency samples are clocked out at the I, Q sample rate regardless of decimation.)
TABLE 13. LINKING CONTROL WORDS FOR SERIAL OUTPUT
DATA TYPE IDENTIFIER DATA TYPE
000 I Data 001 Q Data 010 Magnitude (MAG) Data 011 Phase (PHAS) Data 100 Frequency (FREQ) Data 101 Timing Error (TIMER) Data 110 AGC Gain 111 Zeros
Two examples will illustrate the process of configuring a seria l output using the Serial Output mode.
The serial data stream looks like:
SEROUTA: CONTROL WORD 19 FIELD
start I data word > SEROUTA source data = 000 Q data word > Link following I data = 001
a word > Link following Q data = 011
φ dat Zero data word > Link following φ dat end >
SEROUTB: CONTROL WORD 19 FIELD
start |r| data word > SEROUTB source data = 010
ta word > Link following |r| data = 100
f da TE data word> Link following f da AGC data word > Link following TE data = 110
a = 111
ta = 101
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end >
AGC DATA SERIAL OUTPUT TAG BIT TIMING ERROR DATA SERIAL OUTPUT TAG BIT FREQUENCY DATA SERIAL OUTPUT TAG BIT PHASE DATA SERIAL OUTPUT TAG BIT MAGNITUDE DATA SERIAL OUTPUT TAG BIT Q DATA SERIAL OUTPUT TAG BIT I DATA SERIAL OUTPUT TAG BIT
I (15:0)
(2’s COMP)
Q (15:0)
(2’s COMP)
(O; UNSIGNED BINARY)
|r| (15:0)
φ (15:0)
(2’s COMP)
f (15:0)
(2’s COMP)
TE
(15:0)
(2’s COMP)
AGC
(O; UNSIGNED BINARY)
(15:0)
ZERO
PROCCLK
NUM OF SER WORD LINKS IN A CHAIN
REGREGREGREGREGREGREGREG
SHIFT REG
SHIFT REG
SHIFT REG
SHIFT REG
SERIAL OUT CLOCK DIVIDER SERIAL OUTPUT SYNC POSITION SERIAL OUTPUT CLOCK POLARITY
SERIAL OUTPUT SYNC POLARITY
SHIFT REG
SHIFT REG
SHIFT REG
PROGRAMMABLE
SHIFT REG
MUX
SEROUTB
SOURCE
DIVIDER
HSP50214B
DATA SOURCE FOR SEROUTA LINK FOLLOWING I DATA
LINK FOLLOWING Q DATA LINK FOLLOWING MAG DATA LINK FOLLOWING PHASE DATA LINK FOLLOWING FREQ DATA LINK FOLLOWING TIMING DATA LINK FOLLOWING AGC DATA
FOLLOWS I
SHIFT REG
FOLLOWS Q
SHIFT REG
CROSS MATRIX SWITCH
CROSS
MATRIX
SWITCH
DATA SOURCE FOR SEROUTB
FOLLOWS |r|
SHIFT REG
FOLLOWS φ
SHIFT REG
FOLLOWS f
SHIFT REG
FOLLOWS TE
SHIFT REG
FOLLOWS AGC
SHIFT REG
SEROUTA
SOURCE
XXX SOURCE 000 I 001 Q 010 MAG 011 PHASE 100 FREQUENCY 101 TIMING ERROR 110 AGC
ZERO
111
6 5 4 3 2 1 0
SERIAL OUTPUT SHIFT REGISTER
6 5 4 3 2 1 0
SERIAL OUTPUT SHIFT REGISTER
SEROUT
SEROUTB
SERCLK
SERSYNC
Controlled via microprocessor interfacePolarity is programmable
FIGURE 34. SERIAL OUTPUT FORMATTER BLOCK DIAGRAM
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Serial Output Configuration Example 1:
It is desired to output the I data word, followed by the Q data word, followed by the Phase data word on the SEROUTA output. Similarly, it is desired to output the Magnitude data word followed by the Frequency data word, followed by the Timing Error data word, followed by the AGC Level dat a word on the SEROUTB output. Table 14 illustrates how Control Word 19 should be programmed.
TABLE 14. EXAMPLE 1 SERIAL OUTPUT CONTROL SETTINGS
CONTROL
WORD 19
BIT POSITION FUNCTION
30-28 SEROUTA Dat a Source 000 (I) 27-25 SEROUTB Data Source 010 (|r|) 24-21 Number of Serial Word
inks in a Chain
L 20-18 Link following I data 001 (Q) 17-15 Link following Q data 011 (φ) 14-12 Link following |r| data 100 (f)
11-9 Link following φ da
8-6 Link following f data 101 (Timing) 5-3 Link following AGC data XXX (N/A) 2-0 Link following Timing
NOTE: Beca use all but the first data word in the serial output is
identified by the data type that it follows, SEROUTB can only be fully independent of the sequence in SEROUTA if it does not use any of the same data word types. Th is implies a partition as described in Example 1. Once a data word that is used in SEROUTA is called out in SEROUTB, the remaining sequence in SEROUTB will be identical to that portion of SEROUTA sequence that follows the duplicate data type. This follows from using the “Link follows ‘data type’ data” for word linkage.
NOTE: Each type of data word should be used only o nce in each
data with the data type identifier for I, then the part will repeat the I data word until all of the data word locations are filled. In Example 1, if bits 20-18 were erroneously programmed to 000 (I data) then the SEROUTA would be four sequential repeats of the I data word.
Error data
stream. If the “Link following I data” is programmed
ta 111 (Zeros)
Serial Output Configuration Example 2:
It is desired to output only three data words on each serial output. The I data word, followed by the Q data word, foll owed by the Magnitude data word is to be output on SEROUTA. The Q data word followed by the Magnitude data word, followed by the one other data word to be output on SEROUTB. The choices for the remaining dat a wo rd in th e SEROUTB signal are: phase, frequency, AGC level and timing error. Table 15 illustrates how Control Word 19 should be programmed.
BIT
VALUE RESULT
100 (4)
110 (AGC)
TABLE 15. EXAMPLE 2 SERIAL OUTPUT CONTROL SETTINGS
CONTROL
WORD 19
BIT POSITION FUNCTION
30-28 SEROUTA Data Source 000 (I) 27-25 SEROUTB Data Source 001 (Q) 24-21 Number of Serial Word
Links in a C 20-18 Link following I data 001 (Q) 17-15 Link following Q data 010 (|r|) 14-12 Link following |r| data TBD TBD
11-9 Link following φ dat
8-6 Link following f dat 5-3 Link following AGC data XXX (N/A) 2-0 Link following Timing
Error data
hain
a XXX (N/A)
a XXX (N/A)
BIT
VALUE RESULT
011 (3)
XXX (N/A)
The serial data stream looks like:
SEROUTA: CONTROL WORD 19 FIELD
start I data word > SEROUTA source data = 000 Q data word > Link following I data = 001 |r|data word > Link following Q data = 010 end >
SEROUTB: CONTROL WORD 19 FIELD
start Q data word > SEROUTB source data = 001 |r|data word > Link following Q data = 010 TBD data word> Link following | r | data = TBD end >
As shown by this example, once Q was linked to |r| in the SEROU
TA chain, the SEROUTB chain must have |r| following Q, if Q is selected. Figure 35 illustrates the construction of the serial output streams. If
the serial data stream was changed to be a length of four data words, then, by default, the SEROUTA would be whatever is selected for SEROUTB data word 3. SEROUTB would need to identify the fourth data word. Thus, SEROUTA and SEROUTB are not fully independent because they share the Q data word (and by default, the MAGNITUDE follows Q data link and whatever is selected for data word 3 to follow MAGNITUDE data in SEROUTB).
The other signals provide
d with the SEROUTA and SEROUTB are the SERSYNC and the SERCLK. The SERSYNC signal can be programmed in either early or late sync mode. The sync signal is pulsed active low or active high for each information word link of the chain of data created using Control Word 19. Figure 36 shows the four possible configurations of SERSYNC as
programmed using
Control Word 20. As previously discussed, Control Word 20, Bits 17 and 19,
set th
e functionality of the LSB of each data word. These bits may be programmed to be either a logic “0”, logic “1” or as normal data. The fixed states are designed to allow the microprocessor to synchronize to the serial data stream.
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HSP50214B
CONTROL WORD 19, BITS 24-21 = 011
(3 DATA WORDS IN EACH SERIAL OUTPUT)
DATA WORD 1DATA WORD 2DATA WORD 3
IQMAGNITUDE
DATA WORD 1DATA WORD 2DATA WORD 3
QMAGNITUDE
SEROUTA
SEROUTB
THE REMAINING CHOICES FOR THE THIRD LINK ON SEROUTB ARE:
PHASE, FREQUENCY, AGC LEVEL, AND TIMING ERROR
FIGURE 35. EXAMPLE 2 SERIAL OUTPUT DATA STREAM
“NORMAL”
“INVERTED”
“NORMAL”
“INVERTED”
LSB WORD0
12
0
SERSYNC FOLLOWS LSB
01
1
SERSYNC PRECEDES MSB
1
MSB WORD1
0
DATA SHIFT MSB FIRST
1 15 1412215 14 • • •
2
2
0
1
15 14
LSB WORD1
FIGURE 36. VALID SERSYNC CONFIGURATION OPTIONS
The serial direct output can be programmed to output less than 16-bits. New output data preempts old output data, so if SERSYNC is programmed to precede the MSB, then data will shift out until new data comes along. Note that if SERSYNC is programmed to follow the LSB, then a sync will never occur.
Buffer RAM Output Port
The Buffer RAM parallel output mode utilizes a RAM to store output data for future retrieval by either the 8-bit microprocessor that is configuring the PDC or by a 16-bit baseband processing engine (which could also be a microprocessor). Data is output from the RAM only on request and can be obtained from either the 8-bit μP interface or from a 16-bit interface that uses the two LSBytes of AOUT and BOUT. The RAM holds up to eight 80-bit sample sets. Each sample set includes 16-bits of each I, Q, magnitude, phase, and frequency data. The RAM samples are mapped as shown in Table 16. The Buffer RAM controller supports both FIFO and Snapshot modes.
MSB WORD2
• • •
SAMPLE
NOTE: I and Q are sample aligned in time. |r| and
NOTE: Once magnitude is identified to follow Q,
it must be that way on both serial outputs.
3
3
0
2
2
MSB WORD3
• • • 2
LSB WORD2
LATE SERSYNC MODE
EARLY SERSYNC MODE
TABLE 16. RAM DATA STORAGE MAP
RAM
T
SE
0 I 1 I 2 I 3 I 4 I 5 I 6 I 7 I
I
DATA
(000)
(15:0) Q0(15:0) |r|0(15:0) φ0(15:0) f0(15:0)
0
(15:0) Q1(15:0) |r|1(15:0) φ1(15:0) f1(15:0)
1
(15:0) Q2(15:0) |r|2(15:0) φ2(15:0) f2(15:0)
2
(15:0) Q3(15:0) |r|3(15:0) φ3(15:0) f3(15:0)
3
(15:0) Q4(15:0) |r|4(15:0) φ4(15:0) f4(15:0)
4
(15:0) Q5(15:0) |r|5(15:0) φ5(15:0) f5(15:0)
5
(15:0) Q6(15:0) |r|6(15:0) φ6(15:0) f6(15:0)
6
(15:0) Q7(15:0) |r|7(15:0) φ7(15:0) f7(15:0)
7
Q
DATA
(001)
|r|
DATA
(010)
Φ
DATA
(011)
φ are sample
aligned in time, but one sample delayed from I or Q. The frequency sample is delayed in time from I or Q by 1 sample time + 63 tap FIR impulse response. If the FIR is set to decimate, the FIR output will be repeated every sample time until a new value appears at the filter output. (i.e., the frequency samples are clocked out at the I, Q sample rate regardless of decimation.)
F
DATA
100)
(
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The FIFO mode allows the processor to service the interface only when enough samples are present in the RAM. This mode is provided so that the μProcessor does not have to service the PDC every output sample. An interrupt, INTRRPT, is asserted when the desired number of samples are available. The PDC can be programmed to assert the interrupt when up to 7 samples are available. Control Word 21, Bit 15 is used to set the Buffer RAM controller to the FIFO mode, while Control Word 21, Bits 12-14 set the number of RAM samples to be stored (0 to 7) before the interrupt (
INTRRPT) is asserted. Control Word 20, Bit 24 determines whether the RAM output interface is the 8-bit microprocessor interface or the 16-bit processor interface. In the 16-bit interface the MSByte is sent to AOUT(7:0) while the LSByte is sent to BOUT(7:0).
The
INTRRP output signal goes low for 8 PROCCLK cycles when the number of samples in the Buffer RAM (depth) reaches the programmed depth. The depth of the RAM is calculated using Equation 23. A DSP microprocessor or the data processing engine can use the
INTRRP signal to know
that the RAM is ready to be read.
D
RAM
ADDR
ADDR
()1]
WRITE
READ
[=
MOD8
(EQ. 23)
I
16
I
16
Q
16
|r|
φ ƒ
SEQUENCER
NEW
DATA
FIGURE 37. 16-BIT MICROPROCESSOR INTERFACE BUFFER
TABLE 17. BUFFER RAM OUTPUT SELECT DEFINITIONS
MUX
16 16
WRITE
SEL(2:0) OUTPUT DATA TYPE
000 I Data 001 Q Data 010 Magnitude 011 Phase 100 Frequency
DUAL PORT
RAM
DATA INPUT
“SET OF WORDS”
ADDRESS
SEQUENCER
INCR
WR
PROCCLK
RAM MODE BLOCK DIAGRAM
INCR
RD
DATA OUTPUT
Q |r|
φ ƒ
STATUS
0 1 2 3
MUX
4 6
OUTPUT
DATA
OEBL
SEL(2:0)
FIFO Operation Via 16-Bit μProcessor Interface
Figure 37 shows the conceptual configuration of the 16-bit
μProcessor interface. Th μProcessor read-only microprocessor interface. The
SEL(2:0) lines are the address bus and the OEAL and OEBL lines are the read lines. The address is decoded as shown in Table 17.
Use of the 16-bit interface for Buf Control Word 20, Bit 25, to be set to a logic “0” and Control Word 20, Bit 24, to be set to a logic “1”. Once the Control Word 20 has been set to route data to AOUT(7:0) and BOUT(7:0), then the microprocessor must place a value on the PDC input pins SEL(2:0), to choose which data type will be output on AOUT(7:0) and 6BOUT(7:0). Table 17 defines the data types in terms of SEL(2:0). With the control lines set, the selected
data is read MSByte on AOUT(7:0) and LSByte on BOUT(7:0) when New data only read when bit modes. Programming SEL(2:0) = 110 outputs a 16-bit status signal on AOUT and BOUT. The FIFO status includes FULL, EMPTY, FIFO Depth, and READYB. These status signals are defined in Table 18.
is interface looks like a 16-bit
fer RAM output requires
OEAL and OEBL (are low).
OEBL goes low, so use μP for 8-
101 Unused 110 Memory Status
111 Reading this address increments to the next
ple set
sam
TABLE 18. STATUS BIT DEFINITIONS
AOUT BIT
ATION INFORMATION
LOC
(7:5) FIFO depth - When in FIFO mode, these bits are
current depth of the FIFO.
the
4 EMPTY - When in FIFO mode, the FIFO is
3 FULL - When in FIFO mode, the FIFO is full, and
2 READYB - When in FIFO mode, the output
1-0 GND
NOTE: In the Status output, BOUT(7:0) are all GND.
, and the read pointer cannot be
empty advanced. Active High.
samples will not be written.
new Active High.
fer has reached the programmed threshold.
buf In the snapshot mode, the programmed number of samples have been taken. Active Low.
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Figure 37 shows the interface between a 16-bit microprocessor (or other baseband processing engine) and th
e Buffer RAM Output Section of the Programmable Down Converter, configured for data output via the parallel outputs AOUT and BOUT. In the 16-bit microprocessor interface configuration, the Buffer RAM pointer is incremented when the μProcessor reads address SEL(2:0) = 7 and
OEBL = 0.
INTRRP
OEAL,
OEBL
SEL(0:2)
8 CLKS
> 4 CLKS
0147 01
After reset, the FIFO must be incremented to read the first sample set. This is because the RAM read and write pointers cannot point to the same address. Thus, the FIFO pointer must move to the next address before reading the next set of data (I, Q, |r|, φ, and f) samples. 4 PROCCLK cycles are required after an increment before reading can resume. The FIFO write pointer is reset to zero (the first data sample) when Control Word 22 is written to via the 8-b it mi croprocessor interface. See the Microprocessor Read Section for more detail on how to obtain the Buffer RAM output with this technique. Figure 39 shows the timing diagram required fo r parallel output operations. In this diagram, only the I, Q and Freque
ncy data are taken from each sample before incrementing to the next sample. Figure 39 assumes that the pointer has already been incremented into a sample.
NOTE: For the very first sample read, the pointer must be
incremented first and 4 PROCCLKs must pass before
this sample can be read.
Figure 38 shows INTRRP going low before the FIFO is read. The FIFO can be read before the
number of samples reaches the INTRRP pointer. The number of samples in the FIFO must be monitored by the user via a status read.
INTRRP
PDC
HSP50214B
FIGURE 38. INTERFACE BETWEEN A 16-BIT
MICROPROCESSOR AND PDC IN FIFO BUFFER
OEAL
AOUT(7:0)
OEBL
BOUT(7:0)
SEL(2:0)
INT
RD
D(15:8)
16-BIT
μP
D(7:0)
A(2:0)
AOUT(7:0),
BOUT(7:0)
PROCCLK
FIGURE 39. TIMING DIAGRAM FOR PDC IN FIFO MODE WITH
IQFR IQ
1234 12345678
OUTPUTS I, Q, AND FREQUENCY SENT TO AOUT(7:0) AND BOUT(7:0)
Suppose the depth of the Buffer RAM Output Section is prog
rammed for an
INTRRP pointer depth of 4. If the output is at 4 times the baud rate, the processing routine for the microprocessor may only need to read the buffer when the Buffer RAM had 4 samples since processing is usually on a baud by baud basis.
Figure 39 illustrates the conceptual view of the FIFO as a circular buffer, with the Write address one step ahead of the Rea
d Address.
Figure 40A deals with clockwise read and write address incrementing. The FIFO depth is the
difference between the Write and Read pointers, modulo 8. Figure 40B illustrates a FIFO status of Full, while Figure 40C illustrates a FIFO empty status condition. Figure 40D illustrates a programmed FIFO depth of 3 and the INTRRP signal indicating that the bu
ffer has sufficient data to be read.
Following some simple rules for operating the FIFO will el
iminate most operational errors:
Rule #1: The Read and Write Pointers cannot point at the same add
ress (the circuitry will not allow this).
Rule #2: The FIFO is full when the Write Address = Read Addre
ss -1 (no more data will be written until some samples
are read or the FIFO is reset). Rule #3: The FIFO is empty when the Read Address =
(W
rite Address -1) (the circuitry will not allow the read
pointer to be incremented). Rule #4: You cannot write over what you have not read. Rule #5: RESET places the Write address pointer = 000 and
Rea
d address pointer = 111.
Rule #6: The best addressing scheme is to read the FIFO un
til it is empty. This avoids erroneous and provides for simple FIFO depth monitoring. The interrupt is generated when the depth increments past the threshold.
39
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5
4
HSP50214B
FIFO Operation Via 8-Bit μProcessor Interface
The Buffer RAM Output may also be accessed via the 8-bit microprocessor interface C(7:0). Figure 41 shows the
0
FIFO
DEPTH
1
23
Control Word 20, Bit 24 must be set to 0 in order to obtain Buffer RAM data to this output. The Microprocessor Read Section describes how to read the data from each sample out of the C(7:0) interface.
conceptual configuration of the 8-bit μproce
ssor interface.
WRITE
FIGURE 40A. FIFO DEPTH IS (WRITE - READ)
WRITE
67
5
4
FIGURE 40B. FIFO FULL IS WHEN (WRITE - READ) = 7
67
5
4
0
1
23
0
1
23
READ
READ
WRITE
Recall that
INTRRP stays low for 8 PROCCLK cycles. The FIFO can be read before the INTRRP signal goes low; the number of samples in the FIFO must be monitored by the user. The timing relationship of the
INTRRP to the snapshot data is
shown in Figure 42. The read pointer of the FIFO is incremented when Control
W
ord 23 is written to. The data cannot be read from the next sample until 4 PROCCLKs after the Buffer RAM pointer has been incremented. Control Word 22 is used to reset the Read and Write pointers of the Buffer RAM output to the first sample to 000 and 007 for write and read respectively.
FIGURE 40C. FIFO EMPTY IS WHEN (WRITE - READ) = 1
READ
67
5
4
WRITE
FIGURE 40D. FIFO READY IS WHEN (WRITE - READ) > DEPTH
FIGURE 40.
0
1
23
READY
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DATA
CONTROL
WORD 23
A(2:0)
RD
16
I
16
Q
16
|r|
φ ƒ
SEQUENCER
MUX
16 16
WRITE
WRITE
ADDRESS “5”
0: I;Q (2’s COMP) 1: |r|;
φ (O; UNSIGNED BINARY; 2’s COMP)
2:
ƒ (2’s COMPLEMENT)
4: INPUT AGC (O; UNSIGNED BINARY) 5: AGC; TIMING (O; UNSIGNED BINARY;
DUAL PORT
RAM
DATA INPUT
“SET OF WORDS”
ADDRESS
SEQUENCER
INCR
WR
R2, R1, R0
A2, A1, A0
2’s COMP)
FIGURE 41. 8-BIT MICROPROCESSOR INTERFACE BUFFER RAM MODE BLOCK DIAGRAM
INCR
RD
I Q |r|
φ ƒ
DATA OUTPUT
STATUS
0 1 2 3 4
0
MUX
R0R1
A1
INT(15:0)
INT(22:16)
TIMING
HSP50214B
LSByte
0
MUX
1
R2
1
MSByte
A0
0
1
2
AGC
MUX
3
R0 A1
MUX
0
1
MUX
A1A2 A0
OUTPUT
DATA
R2 R1 R0 A2 A1 A0 SELECTION
000000RAM I LSB 000001RAM I MSB 000010RAM Q LSB 000011RAM Q MSB 001000RAM |r| LSB 001001RAM |r| MSB 001010RAM φ LSB 001011RAM φ MSB 010000RAM ƒ LSB 010001RAM ƒ MSB 011XXXNOT USED 100000INPUT INTEG LSB 100001INPUT INTEG NMSB 100010INPUT INTEG MSB 101000AGC LSB 101001AGC MSB 101010TIMING LSB 101011TIMING MSB 11XXXXNOT USED XXX111STATUS
PROCCLK
I/Q
R/
φ
DATARDY
(I/Q SELECTED)
DATARDY
(R/φ SELECTED)
INTRRP
WRITES TO
SNAPSHOT
RAM
DELA Y TO DATARDY DEPENDS ON LENGTH OF FIR IF FREQ CHOSEN
IQR
FIGURE 42. RAM LOAD SEQUENCE
Snap Shot Operation
The snapshot mode takes sets of adjacent samples at programmed intervals. It is provided for tracking algorithms that do not require processing of every sample, but do require sets of adjacent samples. For example, bit sync algorithms have narrow loop bandwidths that may not need to be updated every sample. Computing the bit phase may require 4 adjacent samples at 2 times the baud rate. The snapshot mode allows the processor to implement the tracking algorithms for high speed data without having to handle every data sample.
The interval from the start of one sna second snapshot is programmed into bits 11-4 (where bit 11 is the MSB) of Control Word 21. The actual interval is the
pshot to the start of a
ƒ
φ
value programmed plus 1. If bits 11-4 = 11111111, then the interval is set to 256. If sample sets are to be taken every 4 samples, then bits 11-4 = 00000011.
Figure 43 shows the relationship between the snapshot samples and the snapshot interval.
ADJACENT
SAMPLES
01234
# SAMPLES = 4
INTERVAL = 64
FIGURE 43. SNAP SHOT SAMPLING
6362
64 65
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The PDC begins to fill the buffer each time an interval number of samples have passed. The number of sample sets the PDC writes into the buffer and is programmed into bits 3-0 of Control Word 21. The number of samples stored is the programmed value and may be from 1 to 8 sample sets. A sample set consists of I, Q, | r | , φ an
d ƒ.
In snap shot operations, the buffer is read the same as for FIFO ope
rations. Figures 37 and 39 describe the Design Blocks and Timing required to output data on AOUT(7:0) and BOUT(7:0). T
able 17 summarizes the selectable output signals. The method for reading data through the Microproce
ssor Section in snap shot mode is identical to the method described in the FIFO mode subsection and the Microprocessor Read Section.
Avoiding Timing Pitfalls When Using the Buffer RAM Output Port
In snapshot mode, the whole buffer is written whenever the interval counter has timed-out. After time-out, old data can be written over. Thus, the data contained within the buffer must be retrieved before time-out to avoid data loss.
It may be desirable to disable the controlling microprocessor during read cycles to avoid the generating extra interrupts. Figure 44 details how the WRITE address can trigger extra interrupts. Care must be taken to eithe
r read sufficient data out of memory or RESET the addressing to ensure that a complete set of data is the cause of the interrupt.
INTRRP
WRITE
ADDRESS
WR RD WR
A COMPLETE SET OF 3 DATA SAMPLES IS IN MEMORY AT INTRRP
A: NORMAL READ/WRITE SEQUENCE
INTRRP
WRITE
ADDRESS
WR RD WR
THE THIRD INTERRUPT HAS ONLY 1 NEW DATA ENTRY
B: FALSE TRIGGERED INTERRUPT READ/WRITE SEQUENCE
FIGURE 44. AVOIDING FALSE INTRRP ASSERTIONS
INTRRP
INTRRP
(INSTEAD OF 3) AT INTRRP
INTRRPT into the
INTRRP
TIME
WR RD
REEST
INTRRP
RD
RD
WR
TIME
Microprocessor Write Section
The Microprocessor Write Section uses an indirect addressing scheme where a 32-bit data word is first loaded in a four 8-bit byte master registers using four writes via C(7:0). The desired destination register address is then written to another address using C(7:0). Writing this address triggers a circuit that generates a pulse, synchronous to clock, that loads the Destination Register . The sync circuit s and dat a words are synchronized to different clocks, CLKIN or PROCCLK, depending on the Destination Registers.
A(2:0) determines the destination for the data on bus, C(7:0). T
able 19 shows the address map for microprocessor interface. Figure 45 shows the Control Register loading sequence. The data in C(7:0) and loaded into the PDC on the rising edge of WR and is latched into the Master Register on the rising edge of WR and A(2:0) = 100. Four clocks must pass before loading the next Contro l Word to guarantee that the data has been transferred.
Some registers can be loaded (i.e., transferred from the Maste
r Register to a Configuration Register or from a Holding Register to an active register) by initiating a sync. For example, to load the AGC Gain, the value of the AGC gain is first loaded into the Holding Registers, then a transfer is initiated by SYNCIN2 if Control Word 8, Bit 29 = 1. This allows the AGC gain to be loaded by detecting a system event, such as a start of a new burst. Bit 20 of Control Word 0 has the same effect on the Carrier NCO center frequency for assertion of SYNCIN1, except it transfers from a dedicated holding register - not the Master Register.
TABLE 19. DEFINITION OF ADDRESS MAP
A2-0 REGISTER DESCRIPTION
0 Holding Register 0. Transfers to bits 7-0 of the 32-bit
estination Register. Bit 0 is the LSB of the 32-bit register.
D
1 Holding Register 1. Transfers to bits 15-8 of a 32-bit
estination Register.
D
2 Holding Register 2. Transfers to bits 23-16 of a 32-bit
estination Register.
D
3 Holding Register 3. Transfers to bits 31-24 of a 32-bit
estination Register. Bit 31 is the MSB of the 32-bit
D register.
4 This is the Destination Address Register. On the fourth CLK
following a wr Registers are transferred to the Destination Register. All 8 bits written to this register are decoded into the Destination Register Address. The configuration destination address map is given in the tables in the Control Word Section.
5 Selects data source for reading. See Microprocessor Read
Section.
ite to this register, the contents of the Holding
Suppose a (0018D038)H needs to be loaded into Control Word 0, the
n Table 20 details the steps to be taken.
address map in A(2:0) is
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TABLE 20. EXAMPLE PROCESSOR WRITE SEQUENCE
STEP A(2:0) C(7:0) COMMENT
1 000 0011 1000 Loads 38 into Master Register
7:0) on rising edge of
(
2 001 1101 0000 Loads D0 into Master Register
15:8) on rising edge of
(
3 010 0001 1000 Loads 18 into Master Register
4 011 0000 0000 Loads 00 into Master Register
5 100 0000 0000 Load “0018D038” into
6 Wait 4 CLKS.
CLK =
(PROCCLK,
CLKIN)
WR
A2-0
C7-0
01234
LSB MSB
23:16) on rising edge of
(
31:24) on rising edge of
(
nfiguration Control Register 0.
Co
1
23
ADD
WR.
WR.
WR.
WR.
4
0
PROCLK
WR RD
A2-0
C7-0
LOAD ADDRESS
OF TARGET
CONTROL REGISTER
FIGURE 46. READING THE CONTROL REGISTERS USING A
TABLE 21. PROCESSOR READ SEQUENCE (INPUT LEVEL
STEP A(2:0) C(7:0) COMMENT
1 101 100 Write Read Code, 100 to
2
2 000 1111 1000
5
READ CODE C(2:0)
LATCH CODE EQUAL T O A 5, A READ ADDRESS AND A READ CODE
SELECTOR)
(F
READ ADDRESS
THREE-STATE
INPUT BUS
Addr generate rising edge.
Drop RD low, Read AGC LSB.
4)H
OUTPUT DATA C(7:0)
ASSERT RD
TO ENABLE DATA
OUTPUT ON C0-7
WR pulled high to
ess 5,
LOAD
CONFIGURATION
DATA
FIGURE 45. LOADING THE CONTROL REGISTERS WITH
32-BIT CONTROL WORDS
LOAD ADDRESS OF
TARGET CONTROL
REGISTER AND
WAIT 4 CLKs
LOAD NEXT
CONFIG­URATION
REGISTER
Microprocessor Read Section
The microprocessor read uses both read and write procedures to obtain data from the PDC. A write must be done to location 5 to select the source of data to be read. The read source is determined by the value placed on the lower three bits of C(7:0). The output from a particular read code is selected using a read address placed on A(2:0). The output is sent to C(7:0) on the falling edge of
If the Read Address is equal to 111, the Read Code is ignored, and the status bits shown in Table 22 in the Output Section is sent to C(7:0). This st
ate was provided so that the
user could obtain the status bits quickly. Refer to the Timing Diagram in Figure 46. Suppose the inpu t
level detector has a hex value of (321AF5)H, then Table 21 details the steps to be taken.
RD.
3 001 0001 1010
(1
4 010 0011 0010
TABLE 22. DEFINITION OF ADDRESS MAP
READ
CO
DE C(2:0)
000 Buffer RAM
001 Buffer RAM
010 Buffered
011 Not Used
100 Input Level
32)H
(
STATUS
TYPE READ ADDRESS A(2:0)
I and Q
Output (|r| and φ)
uency
Freq
Detector
Pull RD high, then drop low,
A)H
Read AGC NLSB. Pull RD high, then drop low,
Read AGC MSB.
000- I LSB. 001- I MSB. 010- Q LSB. 011- Q MSB. See Output Section.
000- MAG LSB (7-0). 001- MAG MSB (15-8). 010- PHASE LSB (7-0). 011- PHASE MSB (15-8). See Output Section.
000- FREQ LSB. 001- FREQ MSB. See Output Section.
Input AGC 000- input AGC LSB (0-7). 001- input AGC NLSB (8-15). 010- input AGC MSB (16-23).
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TABLE 22. DEFINITION OF ADDRESS MAP (Continued)
2:0)
STATUS
TYPE READ ADDRESS A(2:0)
AGC (must write to location 10 to and Timing Error
ple)
sam
000- AGC LSB (lower 8-bits of linear
ol Word 3 used by multiplier)
Contr
mmmmmmmm LSB.
001- AGC MSB (4 shift control bits
and first thre
Word oeeeemmm MSB. This yields
11-bits of the linear control mantissa.
010- Timing error LSB, not stabilized.
011- Timing error MSB, not
abilized.
st
(6:4)-FIFO depth when output is in
FIF
O Buffer RAM Output Mode. (3)-EMPTY signalling the FIFO is empty advanced (Active High). (2)-FULL signalling the FIFO is full and new (Active High). (1)-READYB Output buffer has reached th in FIFO mode or the programmed number of samples have been taken in snapshot mode. (Active Low). (0)-INTEGRATION has been complete and is ready to be read. (Active High).
e bits of linear) Control
and the read pointer cannot be
samples will not be written
e programmed threshold
d in the input level detector
READ
CODE C(
101 AGC Data
110 Not Used 111 Not Used
Don’t Care Status 111- Status (6:0) consisting of
Applications
Composite Filter Response Example
For this example consider a total receive band roughly 25MHz wide containing 124 200kHz wide FDM channels as shown in Figure 47. The design goal for the PDC is to and filter out a single 200kHz FDM channel from the FDM ban
d, passing only baseband samples onto the baseband
processor at a multiple of the 270.8 KBPS bit rate.
to tune
124 CHANNELS
••
FREQUENCY
200kHz
CHANNEL
FREQUENCY
FIGURE 47. RECEIVE SIGNAL FREQUENCY SPECTRUM
RF/IF Considerations
The input frequency to the PDC is dependent on the A/D converter selected, the RF/IF frequency, the bandwidth of interest and the sample rate of the converter. If the A/D converter has sufficient bandwidth, then undersampling techniques can be used to downconvert IF/RF frequencies as part of the digitizing process, using the PDC to process a lower frequency alias of the input signal.
For example, a 70MHz IF can be sampled at 40MHz and the resul
ting 10MHz signal alias can be processed by the PDC to perform the desired downconversion/tuning and filtering. If the IF signal is less than 1/2 the sample frequency then standard oversampling techniques can be used to process the signal. Of the two techniques, only undersampling allows part of the down conversion function to be brought into the digital domain just through sampling, assuming that a sampling frequency can be found that keeps the alias signals low and that the A/D converter has the bandwidth to accept the unconverted analog signal.
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PDC Configuration
For this example, the PDC is configured as follows:
CLKIN: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39MHz
Mode: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Gated
Input Format: . . . . . . . . . . . . . As required by Digital Source
Carrier NCO Fc: . . . . . . . .As determined by Channel Freq.
Carrier NCO Phase Offset: . . . . . . . . . . . . . . . . . . . . . . . . .0
Carrier NCO Offset Frequency: . . . . . . . . . . . . . . . .Disabled
CIC Filter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enabled
Decimation: . . . . . . . . . . . . . . . . .
PROCCLK:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28MHz
Half Band Filters: . . . . . . . . . . . . . . . . . . HB3 and 5 Enabled
FIR Filter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gsmtemp file
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . fS = 541.667kHz
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Decimation = 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Passband: 90kHz
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transition Band: 25kHz
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Passband Atten: 3dB
. . . . . . . . . . . . . . . . . . . . . . . . . Stop Band Atten: 111.25713
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .FIR Order: 90
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FIR Symmetry: Even
Resampling Filter: . . . . . . . . . . . . . . . . . . . . . . HB1 Enabled
The basis for this configuration is:
. . . . . . . . . . . . . . . . . . .18
References
For Intersil documents available on the web, see www.intersil.com/
[1] HSP50210 Data Sheet, [2] Cellular Radio and Personal Communications: A Book
lected Readings, Theodore S. Rappaport, 1995 by
of Se
IEEE, Inc.
[3] AN9720 Application Note, Intersil Corporation,
“Calculating Maximum Processing Rates of the PDC (HSP50214B)”.
[4] FO-007 Block Diagram of HSP50214.
Intersil Corporation, FN3652.
Sampling Rate: Sele Output Rate: 1.083MHz (4x Bit Rate; 8x Baud Rate) CIC Filtering: Primarily Rate Reduction (39/18 = 2.166MHz). HB Filtering: Flat passband with rate reduction by 4 - low
enough (541.66kHz) for sufficient FIR Taps to be used. FIR Filtering:
suppression. Polyphase/HalfBand Filtering:
8x baud rate or 4x bit rate. The CIC and halfband filter responses are shown in Figures
48A and 48B. The composite filter response co
halfband filter 5 and the FIR filter, are shown in Figure 48C and 48D.
For a more detailed discussion of design approaches and tra
des when designing with the PDC, refer to AN9720 [3],
“Calculating the Maximum Processing Rates of the PDC”.
ct a high rate PROCCLK
Primary shaping filter/set final out of band
Interpolate by two to output
nstrained primarily by
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10
-10
-30
-50
-70
MAGNITUDE (dB)
-90
-110 fS = CIC INPUT RATE
-130
10
-10
-30
10
-10
-30
-50
-70
MAGNITUDE (dB)
-90
-110 fS = CIC INPUT RATE
FREQUENCY
f
S
R
-130
FREQUENCY
FIGURE 48A. CIC FILTER RESPONSE FIGURE 48B. HB3 FILTER RESPONSE
10
fS = CIC INPUT RATE
-10
-30
f
S
R
-50
-70
MAGNITUDE (dB)
-90
-110
-130
-50
-70
MAGNITUDE (dB)
-90
-110
fS = CIC INPUT RATE
FREQUENCY
f
S
R
-130
FREQUENCY
FIGURE 48C. HB5 FILTER RESPONSE FIGURE 48D. 255 FIR TAP FILTER RESPONSE
10
fS = CIC INPUT RATE
-10
-30
-50
-70
MAGNITUDE (dB)
-90
-110
f
S
R
-130 FREQUENCY
FIGURE 48E. COMPOSITE FILTER RESPONSE
FIGURE 48. PDC FILTER FREQUENCY SPECTRUMS EXAMPLE (NORMALIZED T
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Configuration Control Word Definitions
Note that in the Configuration Control Register Tables, some of the available 32-bits in a Control Word are not used. Unused bits do not need to be written to the Master Register. If the destination only has 16-bits, then only 2 bytes need to be written to the Master Register. Figure 45 details the timing
CONTROL WORD 0: CHIP CONFIGURATION, INPUT SECTION, CIC GAIN (SYNCHRONOUS TO CLKIN)
BIT
PO
SITION FUNCTION DESCRIPTION
31-21 Reserved Reserved.
for proper operation of the Microprocessor Write Section. Bits identified as “Reserved” should be programmed to a zero.
NOTE: CLKIN or PROCCLK must be present to properly load
control words. Note in the header which is applicable.
20 Carrier NCO External
Sync Enable
19 CIC External Sync
18 Input Format 0- Two’s Complement Input Format.
17 Input Mode 0- Input operates in Gated Mode.
16-13 CIC Shift Gain These bits control the barrel shifter at the input to the CIC filter. These bits are added to the
12-7 CIC Decimation
6 CIC Bypassed Active high, this bit routes the output of the input shif
Enable
Counter
Preload
0- The SYNCIN1 pin has no effect on the Carrier NCO. 1- When the SYNCIN1 pin is asserted, the carrier holding registers to the active register. Also, if bit 0 of this word is active, the carrier phase accumulator feedback will be zeroed to set the Carrier NCO to a known phase, allowing the NCOs of multiple parts to be initialized and updated synchronously.
0- The SYNCIN1 pin has no effect on the CIC filter. 1- When the SYNCIN1 pin is asserted, the decima counters in multiple chips to be synchronized. When CW27 bit-22 is set to a 1, SYNCIN1 will reset both front end and back end circuitry.
1- Offset Binary Input Format.
1- Input operates in Interpolated Mode.
INADJ(2:0) pins to determine the total shift. The sum is saturated at 15. See the CIC Decimation Filter
GA Section for values to be programmed in this field based on CIC filter Decimation. Bit 16 is the MSB. SG = Floor [39 - (number of input bits) - 5log SG = 15 for R = 4. SG = 0 for R = 32.
These bits control the decimation in the CIC filter. Program this field to R-1, where R is the desired decimation factor in the filter. The decimation factor range is 4-32. See CIC Filter Section for effective decimation range relative to the CIC Shift Gain value. Bit 12 is the MSB. While this field allows values from 0 - 63, the valid values are in the range from 4- 32.
When the CIC filter is bypassed, CLKIN must be at least toggled to achieve this). When the CIC filter is bypassed, the bottom 24-bits of the barrel shifter output are routed to the halfband filters.
center frequency and phase are updated from the
tion counter is loaded, allowing the decimation
(R)] for 4 < R < 31
2
ter to the output of the CIC with no filtering.
twice the input sample rate (ENI should be
5-4 Number of Offset
3 Syncout CLK Select This bit selects whether the SYNCOUT signal is generated from CLKIN of from PROCCLK
2 Clear Phase Accum 0- Enable accumulator in Carrier NCO.
1 Carrier NCO Offset
0 Carrier NCO Load
Frequency Bits
equency Enable
Fr
Phase Accum On Update
00 - 8-bits. 01 - 16. 10 - 24. 11 - 32.
0- CLKIN. 1- PROCLK.
1- Zero feedback in accumulator. When set to 1, this bit enables the offset frequency word to be added to the center frequency Control
Word. The offset is loaded serially via the COF and COFSYNC pins. When this bit is set to 1, the μP update to the Car
using SYNCIN1 will zero the feedback of the phase accumulator, as well as update the phase or frequency. This function can be used to set the NCO to a known phase synchronized to an external event.
rier NCO frequency or an external carrier NCO load
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CONTROL WORD 1: INPUT LEVEL DETECTOR (SYNCHRONOUS TO CLKIN)
BIT
SITION FUNCTION DESCRIPTION
PO
31 Reserved Reserved. 30 Integration Mode 0- Integration of magnitude error stops when the interval counter times out.
29-14 Integration Interval These are the top 16-bits of the 18-bit integration counter, ICPrel. ICPrel = (N)/4+1; where N is the
13-0 Input Threshold Input Magnitude Threshold. Bits 12-0 correspond to input
CONTROL WORD 2: INPUT LEVEL DETECTOR START STROBE (SYNCHRONIZED TO CLKIN)
BIT
SITION FUNCTION DESCRIPTION
PO
N/A Start Input Level
Detector AGC Integrator
1- Integration runs continuously. When the interval coun results of the integration is sent to a register for the processor to read.
ed integration period in CLKIN cycles, defined as the number of input samples to be integrated. N
desir
must be a multiple of 4: [0, 4, 8, 12, 16.... , 2
zeros must be accounted for, as they will be added to the threshold! If the gated input mode is used, the same input sample will be accumulated multiple times.
to this threshold, where the threshold is a signed number. Bit 13 is the MSB.
Writing to this location starts/restarts the input AGC err stop when the integration interval counter times out depending on bit 30 of Control Register 1 (see Microprocessor Write Section).
18
]. Bit 29 is the MSB. If the input is interpolated, then the
ter times out, the integrator reloads, and the
bits 12-0. The magnitude of the input is added
or integrator. The integrator will either restart or
CONTROL WORD 3: CARRIER NCO CENTER FREQUENCY (SYNCHRONIZED TO CLKIN)
BIT
POSITION FUNCTION DESCRIPTION
31-0 Carrier Center
NOTE: In the HSP50214B, if the SYNCIN1 occurs when the NCO is not updating, update.
BIT
SITION FUNCTION DESCRIPTION
PO
31-10 Reserved Reserved.
9-0 Carrier Phase Offset These bits, PO, are used to offset the phase of the carrier
BIT
SITION FUNCTION DESCRIPTION
PO
N/A Carrier Frequency
Frequency
trobe
S
CONTROL WORD 4: CARRIER PHASE OFFSET (SYNCHRONIZED TO CLKIN)
CONTROL WORD 5: CARRIER FREQUENCY STROBE (SYNCHRONIZED TO CLKIN)
These bits control the frequency of the Carrier NCO. The frequency range of the NCO is ± f f
is the input sample rate. The bits are computed by the equation N = (F
S
This location is a holding register. After loading, a transfer to the active register is done by writing to Control Word 5 or by generating a SYNCIN1 with Control Word 0, Bit 20 set to 1. The Carrier NCO only updates
PO = INT[(2 bit offset binary representation. Bit 9 is the MSB. This location is a holding register. After loading, a transfer to the active register is done by writing to Control Word 6 or by generating a SYNCIN1 with Control Word 0, Bit 20 set to 1. The carrier NCO only updates when
Writing to this address updates the carrier frequency Control Word from the Holding Register.
ENI is active.
10
φ
)/ 2π]
off
HEX
; (-π <φ
the load signal is held internal to the part until the next NCO
< π) for 10-bit 2’s complement representation or from 0 to 2π for 10-
off
/ 2 wh ere
/ fS)*232. Bit 31 is the MSB.
NCO
NCO. The bits are computed by the Equation
ENI is active.
S
CONTROL WORD 6: CARRIER PHASE STROBE (SYNCHRONIZED TO CLKIN)
BIT
SITION FUNCTION DESCRIPTION
PO
N/A Carrier Phase Strobe Writing to this address updates the carrier phase offset Control Word with the value written to the phase
fset (PO) register.
of
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CONTROL WORD 7: HB, FIR CONFIGURATION (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
31-22 Reserved Reserved.
21 Enable External
Filter Sync
20 Halfband (HB)
Bypass
19 HB5 Enable 0- Disables HB number 5 (the last in the cascade).
18 HB4 Enable Setting this bit enables HB filter number 4. 17 HB3 Enable Setting this bit enables HB filter number 3. 16 HB2 Enable Setting this bit enables HB filter number 2. 15 HB1 Enable Setting this bit enables HB filter number 1.
14-11 FIR Decimation Load de cimation from 1-16, where 0000 = 16. Bit 14 is the MSB.
10 FIR Real/Complex 0- Complex Filter.
9 FIR Sym Type 0- Odd Symmetry.
8 FIR Symmetry 0- Symmetric Filters.
7-0 FIR Taps Number of taps in the FIR filter. Range is 1 to 255, where 0000000 is invalid.
0- The SYNCIN2 pin has no effect on the halfband and FIR filters. 1- When the SYNCIN2 pin is asserted, the filter control circuitry in resampler, and the discriminator are reset. SYNCIN2 can be used to synchronize the computations of the filters in multiple parts for the alignment (see Synchronization Section).
1- Bypass Halfband Filters. 0- Enable HB Filters (at least one HB must be enabled).
1- Enables HB filter number 5.
0001 - 1 1001 - 9 0010 - 2 1010 - 10 0011 - 3 1011 - 11 0100 - 4 1100 - 12 0101 - 5 1101 - 13 0110 - 6 1110 - 14 0111 - 7 1111 - 15 1000 - 8 0000 - 16
1- Dual Real Filters.
1- Even Symmetry.
1- Asymmetric Filters.
the halfband filters, the FIR, the
CONTROL WORD 8: AGC CONFIGURATION 1 (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
31-30 Reserved Reserved.
29 Sync AGC Updates to
SYNCIN2
28-16 Threshold The magnitude measurement out of the cartesian to polar
15-12 Loop Gain 1
Mantissa
11-8 Loop Gain 1
Exponent
7-4 Loop Gain 0 Mantissa Selected when AGCGNSEL = 0. These bits are MMMM. See description for
3-0 Loop Gain 0
Exponent
When this bit is 1, the SYNCIN2 pin loads the
the gain error. A gain of 1.647 in the cartesian to polar conversion that must be taken into account when computing this threshold. These bits are weighted -2
Selected when AGCGNSEL = 1. These bits, MMMM, together with the exponent bits, EEEE (11-8), set the loop gain for
1.5dB (Threshold -[Magnitude * 1.6]) 0.MMMM * 2 and the threshold is programmed in bits 28-16. The decimal value for the mantissa is calculated as DEC(MMMM)/16. Bit 15 is the MSB.
Selected when AGCGNSEL = 1. These bits are EEEE. See description of bits 15-12. Bit 11 is the MSB.
are used for Loop 0. Bit 7 is the MSB. Selected when AGCGNSEL = 0. These bits are EEEE. See
are used for Loop 0. Bit 3 is the MSB.
the AGC loop. The gain adjustment per output sample is:
contents of the master registers into the AGC accumulator.
converter is subtracted from this value to get
2
down to 2
-(15 - EEEE)
-10
where magnitude ranges from 0 to 1.414
description for bits 15-12. Same equations
49
. Bit 28 is the MSB.
bits 15-12. Same equations
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CONTROL WORD 9: AGC CONFIGURATION 2 (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
31-28 Reserved Reserved. 27-16 Upper Limit Maximum Gain/Minimum Signal. The upper four
15-12 Reserved Reserved.
11-0 Lower Limit Minimum Gain/Maximum Signal. The upper four
mantissa in the fractional offset binary: [eeeemmmmmmmm]. See the AGC Section for details. Bit 27 is the MSB. The gain is in dB. G = (6.02)(eeee) + 20log eeee = Floor [log mmmmmmmm = Floor [256(10
mantissa in the fractional offset binary: [eeeemmmmmmmm]. See the AGC Section for details. Bit 1 1 is the MSB. The gain is in dB. G = (6.02)(eeee) + 20log eeee = Floor [log mmmmmmmm = Floor [256(10
(10
2
(10
2
GAIN dB/20
GAIN dB/20
)]
GAIN dB/20/2eeee
)]
GAIN dB/20/2eeee
bits are used for exponent; the remaining bits form the
- 1)]
bits are used for exponent; the remaining bits form the
- 1)]
(1.0 + 0.mmmmmmmm)
10
(1.0 + 0.mmmmmmmm)
10
CONTROL WORD 10: AGC SAMPLE GAIN CONTROL STROBE (SYNCH
BIT
POSITION FUNCTION DESCRIPTION
N/A Sample AGC Gain
BIT
SITION FUNCTION DESCRIPTION
PO
31-6 Reserved Reserved.
5 Enable External
4-3 Number of Offset
2 Enable Offset
1 Clear Phase
0 Timing NCO Phase
Level
CONTROL WORD 11: TIMING NCO CONFIGURATION (SYNCHRONIZED TO PROCCLK)
Timing NCO Sync
equency Bits
Fr
Frequency
Accumulator
Accumulator L Update
oad On
Writing to this location samples the output of the AGC loop filt
0- SYNCIN2 has no effect on the timing NCO. 1- When SYNCIN2 is asserted, the timing NCO center loaded in their holding registers. If bit 0 of this word is set to 1, the phase accumulator feedback is also zeroed.
00 - 8 bits. 01 - 16. 10 - 24. 11 - 32.
0- Zero Offset Frequency to Adder. 1- Enable Offset Frequency.
0- Enable Accumulator. 1- Zero Feedback in Accumulator.
When this bit is set to 1, the μP update to the timing NCO frequency or an external timing NCO load using SYNCIN2 will zero the feedback of the phase accumulator as well as update the phase and frequency. This function can be used to set the NCO to a known phase synchronized to an external event.
RONIZED TO PROCCLK)
frequency and phase are updated with the value
er to stabilize the value for μP reading.
CONTROL WORD 12: TIMING NCO CENTER FREQUENCY (
BIT
SITION FUNCTION DESCRIPTION
PO
31-0 Timing NCO Center
equency
Fr
These bits control the frequency of the timing NCO. The frequency range of the NCO is from 0 to
RESAMP
where F
RESAMP
F the equation: N =(f loading, a transfer to the Active Register is done by writing to Control Word 14 or by generating a SYNCIN2 with Control Word 11, Bit 5 set to 1.
is the input sample rate to the resampling filter. The bits are computed by
OUT
/ F
RESAMP
)*232. Bit 31 is the MSB. This location is a holding register. After
SYNCHRONIZED TO PROCCLK)
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CONTROL WORD 13: TIMING PHASE OFFSET (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
31-8 Reserved Reserved.
7-0 Timing NCO Phase
fset
Of
CONTROL WORD 14: TIMING FREQUENCY STROBE (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
N/A Timing Frequency
trobe
S
CONTROL WORD 15: TIMING PHASE STROBE (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
N/A Timing Phase Strobe Writing to this address updates the active timing NCO Phase Of
CONTROL WORD 16: RESAMPLING FILTER CONTROL (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
31-12 Reserved Reserved.
11-4 Re-Sampler Output
se Delay
Pul
These bits are used to offset the phase of the T iming NCO. The range is 0 to 1 times the resampler input period interpreted either as ± T/2 (2’s complement) or 0 to T (offset binary). Bit 7 is the MSB. This location is a holding register. After loading, a transfer to the Active Register is done by writing to Control Word 15 or by generating a SYNCIN2 with Control Word 11, Bit 5 set to 1.
Writing to this address updates the active timing NCO Frequency Register in the timing NCO (see Timing NCO Section).
Timing NCO Section).
NOTE: These bits program the delay between output samples when interpolating. The extra outputs can
be delayed from 2 to 255 clocks from the first output. A delay of 2 equals 255 clocks of delay. A delay of 0 or 1 is an invalid mode. When interpolating by 2, one extra output is generated; when interpolating by 4, 3 extra outputs are generated. Program by the equation (PROCCLK/f
Bit 11 is the MSB.
NOTE: If less than 5 is programmed, there will not be sufficient time to fully update the output
ffer. If less than 16 is programmed, the serial output may be preempted. This means that
bu it won’t finish and if the sync is programmed to follow the data, there may never be a sync.
fset Register in the timing NCO (see
OUT
) - 1.
3 Re-Sampler Bypass 0- Resampling Filter Enabled. A valid combination of bits 2-0 must also be selected.
polation halfband filters) is bypassed.
2-0 Filter Mode Select;
2- HB2 Enabled 1- HB1 Enabled 0- Re-Sampler Enabled
1- Resampling Filter Section (including Inter 000- Not Valid.
001- Re-Sampler Enabled. 010- Halfband 1 Enabled. 011- Re-Sampler and Halfband Filter 1 Enabled. 100- Not Valid. 101- Not Valid. 110- Both Halfband Filters Enabled. 111- Re-Sampler and Both Halfband Filters Enabled.
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CONTROL WORD 17: DISCRIMINATOR FILTER CONTROL, DISCRIMINATOR DELAY (SYNCHRONIZED TO PROCCLK)
BIT
POSITION FUNCTION DESCRIPTION
31-17 Reserved Reserved. 16-15 Phase Multiplier These bits program allow the phase output of the cartesian to
14 Discriminator Enable 0- Disable Discriminator.
13-11 Discriminator FIR
Decimation
10 FIR Symmetry Type 0- Odd Symmetry.
9 FIR Symmetry 0- Symmetric.
8-3 Number of FIR Taps Number of FIR taps from 1 to 63, where 00000 is not valid (00001 = 1 tap, 00010 = 2 taps, etc. up to 11111
2-0 Discriminator Delay Sets the number of delays from 1 to 8 in the discriminat
8 (modulo 2π) to remove phase modulation before the frequency is measured. 00- No Shift on Phase Input to frequency discriminator. 01- Shift Phase Input to frequency discriminator up 1 (on 10- Shift Phase Input to frequency discriminator 11- Shif t Phase Input to frequency discriminator up 3 (three
1- Enable Discriminator. The decimation can be programmed from 1 to 8, where 00
decimate by 2; 011 = decimate by 3; 100 = decimate by 4; 101 = decimate by 5; 110 = decimate by 6; and 111 - decimate by 7.
1- Even Symmetry.
1- Asymmetric.
aps). Bit 8 is the MSB.
= 63 t
represents 1 delay; 001 represents 2 delays, 01 0 repr esents 3 delays, 011 represen ts 4 delays, 100 represents 5 delays, 101 represents 6 d elays, 110 represents 7 delays, and 111 represents 8 delays. If ddd the decimal representation bits 2-0, then the discriminator a tran sf er fu nction H (Z) = 1 -Z
up 2 (two) bits, discarding the MSB and zero filling the LSB.
polar converter to be multiplied by 1, 2, 4, or
e bit), discarding the MSB and zero filling the LSB.
) bits, discarding the MSB and zero filling the LSB.
0 = decimate by 8; 001 = decimate by 1; 010 =
or. Set delay ddd to de la y minus 1, whe r e 00 0
-(ddd + 1)
.
CONTROL WORD 18: TIMING ERROR PRELOADS (
BIT
POSITION FUNCTION DESCRIPTION
31-28 Reserved Reserved. 27-16 NCO Divide The Re-Sampler NCO output is divided down by the value loa
value that is one less than the desired period. Bit 27 is the MSB.
11-0 Reference Divide The reference clock is divided down by the va
CONTROL WORD 19: SERIAL OUTPUT ORDER (SYNCHRONIZED TO PROCCLK)
BIT
PO
SITION FUNCTION DESCRIPTION
31 Reserved Reserved.
30-28 Data Source for
SEROUTA
27-25 Data Source for
24-21 Number of Serial Word
20-18 Link Following I Data The serial data word, or link, following the I data word is selected using Table 12
SEROUTB
Links in a Chain
is one less than the desired period. Bit 27 is the MSB. A minimum preload of “I” is required.
Serial Output A Source. The serial data source is selected
Serial Output B Source. The serial data source is selected
This parameter determines the number of SERSYNC pulse parameter matches the number of serial words that are linked together to form a serial output chain, then there will be a sync pulse for every word in the serial output. In applications where a processor is receiving the serial data, it may be desirable to have a single SERSYNC pulse for the whole serial output chain, instead of a SERSYNC for each word in the data chain. The processor then parses out the various data words. As an example, if the I and Q are chained together and a single SERSYNC pulse is generated for this serial output chain, no ambiguity exists in the processor about which two data samples (one from I and one from Q) are related.
(see Output Section).
SYNCHRONIZED TO PROCCLK)
ded into this register plus 1. Load with a
lue loaded into this register plus 1. Load with a value that
using Table 12 (see Output Section).
using Table 12 (see Output Section).
s generated. It can be set from 1 to 7. If this
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CONTROL WORD 19: SERIAL OUTPUT ORDER (SYN
BIT
POSITION FUNCTION DESCRIPTION
17-15 Link Following Q Data The serial data word, or link, following the Q data word is selected using Table 12
14-12 Link Following
Magnitude Data
11-9 Link Following Phase
a
Dat
8-6 Link Following
5-3 Link Following AGC
2-0 Link Following Timing
BIT
SITION FUNCTION DESCRIPTION
PO
31-26 Reserved Reserved.
25 Data Source for Least
24 Buffered Output Mode
23-22 AOUT Direct Parallel
21-20 BOUT Direct Parallel
19 Serial Output Sync
18 Serial Output Clock
Frequency Data
ata
Level D
r Data
Erro
CONTROL WORD 20: BUFFER RAM, DIRECT PARALLEL, AND DIRECT SERIAL OUTPUT CONFIGURATION
Significan AOUT and BOUT
Interf
Output Mode Data Source
Output Mode D Source
Pol
Pol
t Bytes of
ace
ata
arity
arity
(see Output Section). The serial data word, or link, following the
(see Output Section). The serial data word, or link, following the PHAS data word is selected using Table 12
(see Output Section). The serial data word, or link, following the
(see Output Section). The serial data word, or link, following the AGC data word is selected using Table 12
(see Output Section). The serial data word, or link, following the TIMER data word is selected using Table 12
(see Output Section).
(SYNCH
Output LSBytes, bits (7:0), of AOUT and BOUT can provide: 0- Buffer RAM Mode Output or, 1- Parallel Direct Mode Output.
Buffered Mode Output interfaces to either: 0- 8-bit μP ( 1- 16-bit μP
The data word sent by the Direct Parallel Output Mode to AOUT is: 00- I Data. (2’s complement) 01- Magnitude. (O; unsigned binary) 1X- Frequency. (2’s complement)
The data word sent by the Direct Parallel Output Mode to BOUT is: 00- Q Data (2’s complement). 01- Phase (2’s complement). 1X- Magnitude (O; unsigned binary).
0- Normal Sync Mode (active high). 1- Sync Inverted (active low).
0- Output Clock Inverted rising edge aligns with data transitions. 1- Output Clock Normal falling edg
RONIZED WITH PROCCLK)
address = μP ASEL(5:#); CLK = μP RAM read). (address = SEL(2:0); CLK = OEBL).
CHRONIZED TO PROCCLK) (Continued)
MAG data word is selected using Table 12
FREQ data word is selected using Table 12
e aligns with data transitions.
1
of the serial word (Early Mode).
17 Serial Output Sync
16-14 Serial Out Clock
13-12 I Data Serial Output
ition
Pos
Divider
Tag Bit
0
0- Sync is asserted one bit time after the last bit of the serial word (Late Mode). 1- Sync is asserted one bit time prior to the first bit
000- Serial Output at PROCCLK/16. 001- Serial Output at PROCCLK/8. 010- Serial Output at PROCCLK/4. 011- Serial Output at PROCCLK/2. 1XX- Serial Output at PROCCLK rate.
00- No Tag Bit. LSB of word is passed. 01- 0 Tag Bit. LSB of word is set to zero. 1X- 1 Tag Bit. LSB of word is set to one.
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CONTROL WORD 20: BUFFER RAM, DIRECT PARALLEL, AND DIRECT SERIAL OUTPUT CONFIGURATION
BIT
POSITION FUNCTION DESCRIPTION
11-10 Q Data Serial Output
Tag Bit
9-8 Magnitude Data Serial
7-6 Phase Data Serial
5-4 Frequency Data Serial
3-2 AGC Data Serial
1-0 Timing Error Data
BIT
SITION FUNCTION DESCRIPTION
PO
31-16 Reserved Reserved.
15 Output Buffer Mode 0- The output buffer operates in snapshot mode.
14-12 FIFO Mode Depth
11-4 Snapshot Mode
3-0 Snapshot Mode
Output T
Output T
Output T
Output T
Serial
Thr
Interval
Number of Samples
ag Bit
ag Bit
ag Bit
ag Bit
Output Tag Bit
CONTROL WORD 21: BUFFER RAM OUTPUT CONTROL REGISTER (
eshold
(
SYNCHRONIZED WITH PROCCLK) (Continued)
(See I Data Serial Output Tag selection above).
(See I Data Serial Output Tag selection above).
(See I Data Serial Output Tag selection above).
(See I Data Serial Output Tag selection above).
(See I Data Serial Output Tag selection above).
(See I Data Serial Output Tag selection above).
SYNCHRONIZED TO PROCCLK)
1- The output buffer operates in FIFO mode. In FIFO mode, when the FIFO depth reaches this threshold, an interrupt is generated and the READY
flag is asserted. The threshold may be set from 0 to 7. Bit 14 is the MSB. The interrupt is generated when the FIFO depth reaches the threshold, as the FIFO fills.
In snapshot mode, the interval between snapshots in bit binary number, i.e. 256, (2 parameter to 1 less than the desired interval. Bit 11 is the MSB.
In snapshot mode, the number of samples stored each time equal to the decimal version of this 4-bit number. The range is 1- 8. Bit 3 is the MSB.
8
), sample time counts between snapshot samples. Program this
the output sample times is determined by this 8-
the snapshot interval counter times out is
CONTROL WORD 22: BUFFER RAM OUTPUT FIFO RESET (SYNCHRONIZED TO PROCCLK)
BIT
PO
SITION FUNCTION DESCRIPTION
N/A FIFO reset A write to this address increments the output FIFO RAM address pointers to READ = 1 11 and WRITE =
CONTROL WORD 23: INCREMENT OUTPUT FIFO (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
N/A FIFO Strobe A write to this address increments the output FIFO/buffer to the next sample set.
(SYNCHRONIZED T
BIT
SITION FUNCTION DESCRIPTION
PO
N/A SYNCOUT Strobe A write to this address generates a one clock period wide strobe o
000.
CONTROL WORD 24: SYNCOUT STROBE OUTPUT PIN
O CLKIN OR PROCCLK DEPENDING ON PROGRAMMING IN CONTROL WORD 0)
n the SYNCOUT pin that is synchronized to the clock. This strobe may be synchronized to CLKIN or PROCCLK based on the programming of bit 3 of Control Word 0.
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CONTROL WORD 25: COUNTER AND ACCUMULATOR RESET (SYNCHRONIZED TO BOTH CLKIN AND PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
N/A Counter and
Accumulator Reset
A write to this address initializes the counters and accumulators for te st in g. Item s t hat are rese t are :
Carrier NCO.
1. Loads phase offset <9:0> into register to be used for adding to accumulator.
2. Enables feedback on the accumulator.
CIC Filter
1. Resets the decimation counter.
2. Clears enables to CIC.
3. Clears accumulators in CIC.
4. Clears enable leaving CIC.
Halfband Filters
1. Resets compute counter in Halfband control.
2. Resets read address for all Halfband Filters.
3. Resets write address for all Halfband Filters.
4. Clears input available strobe.
5. Resets Halfband control logic.
255 Tap FIR
1. Resets FIR read and write address pointers.
2. Zero’s coefficient read address.
AGC Loop
1. Clears accumulator in loop filter.
Re-Sampler and Interpolation Halfband Filters.
1. Resets counters for Halfband addresses for writing.
2. Resets output enable.
3. Reset controller for Re-Sampler.
Timing NCO
1. Initializes counters for inserting extra pulses when interpolating half HSP50214B, a configuration control word bit determines if a Timing NCO reset is executed. If Control Word 27, Bit 20 is set to a logic one, a reset will clear the feedback in the timing NCO phase accumulator. If Control Word 27, Bit 20 is zero, a reset will not clear the timing NCO phase accumulator feedback, which is how the HSP50214 operated.
Discriminator
1. Resets read and write address pointers.
2. Zero’s coefficient read address.
Cartesian to Polar Coordinate Counter
1. Resets Cordic counters (stops cu
FIFO Control
1. Resets decoder for controlling FIFO.
2. Resets write address for FIFO.
3. Clears
4. Resets “depth” and “full” flags.
5. Sets the empty flag.
6. Sets the read address to “7”, write address to “0”.
Snapshot Control
1. Zeros the group number.
2. Load interval counter.
3. Resets write address and read address for FIFO.
Output Serial Control
1. Reloads shift counter.
2. Reloads “Number of Words” counter.
3. Reloads counter for sync (for early or late).
4. Reloads counter for dividing down SERCLK.
5. In the HSP50214B, the Control Word 25 reset signal is designed such that the front end reset is 10
RD and INTRRPT.
CLKIN periods enables will be caught in the pipelines.
wide and the back end reset is 10 PROCCLK periods wide. This guarantees that no
rrent computation).
bands are enabled. In the
55
FN4450.4
May 1, 2007
HSP50214B
www.BDTIC.com/Intersil
CONTROL WORD 26: LOAD AGC GAIN (SYNCHRONIZED TO PROCCLK)
BIT
POSITION FUNCTION DESCRIPTION
(15:12)
(11:5)
(5:0)
PO
19 - 18 Discriminator FIR
eeee - AGC Exponent mmmmmmm - AGC Mantissa 000000 - Not Used
CONTROL WORD 27: TEST REGISTER (SYNCHRONIZED TO CLKIN)
BIT
SITION FUNCTION DESCRIPTION
31-25 Reserved A fixed value of 0000 000 is loaded here for normal operation.
24 RAM Test Enable 0 = Normal Operation; 1 = RAM Test Enabled. The B Ver sion include s test circuit ry for the ROM and RA M
23 Input Level Detector
Preload
Counter Select
22 SYNCIN1 Reset
Control
21 Timing Error Input
Select
20 Timing NCO Reset
17 Input Level Detector
16 AGC Average
15 AGC Clear Inhibit When set to zero, this bit will clear the AGC loop filter accumulator
14 Q Input to Coordinate
13 Coordinate Converter
12-0 Reserved A fixed value 0 0010 0111 1000 [0278]hex is loaded here for normal operation.
ol Select
Contr
Input
ation Start
Integr Select
Control
Converter
- 15)
Input
(see bits 19
AGC LOAD. Writing to this location generates a str (15:5) to the master registers. These bits are loaded into the MSBs of the AGC loop filter accumulator. Bits 15:12 are the exponent associated with the AGC gain shifter, while bits 11:5 are the mantissa associated with the AGC multiplier. The weighting of the AGC mantissa is 01.mmmmmmm. When considering Figure 23, the AGC Block Diagram, note the mux between the Register and the Limiter in the AGC Loop filter. The AGC LOAD controls the mux. Nor output. When the AGC LOAD is asserted via the write command, the mux selects the Write Master Registers for data input See Table 20, Figure 45 and the associated text of the data sheet for an explanation of how data is loaded into the Master Registers for use internal to the part. Note that for the AGC LOAD
that will be loaded on write to CONTROL WORD 26.
blocks tha coefficient RAM’s. This is d one by setting bit 2 4 to zero.
Because the HSP50214 did not require a “write” to Con trol Word 27 and the HSP50214B does requ for the HSP50214 will require modification to work properly with the HSP50214B.
0 = The two LSB’s of the interpolation period preload are se t to zero. 1 = The two LSB’s of the interpolation period preload are se t to one .
0: SYNCIN1 causes only front end reset. 1: SYNCIN1 causes front end and back end resets.
0 = Operates as HSP50214. 1 = Corrects an error in the 4 LSB’s.
0 = Backend reset will not clear the timing NCO phase accumulator feedback. 1 = Backend reset clears the timing NCO phase accumulator.
00 = 18-bits of delayed and subtracte 01 = 18-bits of magnitude from coordinate converter. 1X = 18-bits of resampler/halfband filer I output.
0 = No external sync control of input end detector start/restart of integration period. 1 = SYNCIN causes the input level detector to
0: AGC settles to mean. 1: AGC settles to median.
to CW25. When set to a one, a WRITE to CW25 will not clear
0 = I and Q enabled to coordinate converter. I = Q input to coordinate converter is zeroed.
0 = The Resampler HB filter output is routed to coordinate converter. 1 = The output of 255 tap FIR is routed to coordinate converter.
A fixed value 0 0010 0111 1010 [027A]hex is loaded here for 7FFF.
t was not present in the original release part. This circuitry must be disabled before loading the
ire that Control Word 27, Bit 24 be set to zero for normal operation, software that was written
only the lower 16-bits require data be valid to ensure a proper write of an AGC Value
d (optionally shifted) phase.
obe to load the AGC loop accumulator with bits
mally the mux would select the limiter
start/restart its integration period.
on a SYNCIN2 assertion or a WRITE
the AGC loop filter accumulator.
setting the Sin/Cos Generator outputs to
56
FN4450.4
May 1, 2007
HSP50214B
www.BDTIC.com/Intersil
CONTROL WORDS 64-95: DISCRIMINATOR COEFFICIENT REGISTERS (SYNCHRONIZED TO PROCCLK)
BIT
SITION FUNCTION DESCRIPTION
PO
31-10 Discriminator FIR
Coefficient
CONTROL WORDS 128-255: 255 PROGRAMMABLE COEFFICIENT REGISTERS
BIT
SITION FUNCTION DESCRIPTION
PO
31-10 Programmable FIR
ficient
Coef
The discriminator FIR coefficie are loaded from the center coefficient at address 64 to the last coefficient. If the filter is asymmetric the coefficients C coefficients.
The programmable FIR coefficients are 22-bit-two’s complement. If the filter is symmetric, the coefficients are loaded from the center coefficient at address 128 to the last coefficient. If the filter is asymmetric the coefficients C of asymmetric coefficients. Real Filters are computed as: Xn-k+1 Ck1 + Xn-k+2 Ck-2 + ... XnC0), where C0 is the coefficient in address 128 and Xo is the oldest data sample.
Complex filters outputs are computed as follows: Xn is the most recent data sample.
k is the number of samples = number of (complex) taps. C0_re is the coefficient loaded into CW128. C0_im is the coefficient loaded into CW129.
The convolution starts with the oldest data, times the last complex coef data, times the first complex coefficient loaded.
Iout = (-Xn-k+1_q * Ck-1_im + Xn-k+1_i * Ck-1_re).
Qout = (Xn-k+1_i * Ck-1_im + Xn-k+1_q * Ck-1_re).
to CN are loaded with C0 in address 64 up to 64+N, where N is number of asymmetric
0
+ (-Xn-k+2_q * Ck-2_im + Xn-1+2_i * Ck-2_re). + ... + (-Xn_q * C0_im + Xn_i * C0_re).
+ (Xn-k+2_i * Ck-2_im + Xn-1+2_q * Ck-2_re). + ... + (Xn_i * C0_im + Xn_q * C0_re).
nts are 22-bit-two’s complement. If the filter is symmetric, the coefficients
to CN are loaded with C0 in address 128 up to 128+N, where N is number
0
ficient, and ends with the newest
57
FN4450.4
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HSP50214B
www.BDTIC.com/Intersil
Absolute Maximum Ratings Thermal Information
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7.0V
Input, Output or I/O Voltage. . . . . . . . . . . . GND-0.5V to V
ESD Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Class 2
CC
+0.5V
Operating Conditions
Voltage Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . +4.75V to +5.25V
Temperature Range
Commercial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
Industrial. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C
Input Low Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +0.8V
Input High Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2V to V
Input Rise and Fall Time . . . . . . . . . . . . . . . . . . . . . . . . . 1V/ns Max
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
is measured with the component mounted on an evaluation PC board in free air.
4. θ
JA
CC
Thermal Resistance (Typical, Note 4)
MQFP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +150°C
Maximum Storage Temperature Range. . . . . . . . . .-65°C to +15
Pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
θ
JA
(°C/W)
0°C
DC Electrical Specifications V
PARAMETER SYMBOL TEST CONDITIONS MIN MAX UNITS
Logical One Input Voltage V Logical Zero Input Voltage V Clock Input High V Clock Input Low V Output High Voltage V Output Low Voltage V Input Leakage Current I Standby Power Supply Current I Output Leakage Current I Operating Power Supply Current I
Input Capacitance C Output Capacitance C
NOTES:
5. Power Supply current is proportional to operation frequency. Typical rating for I
6. Capacitance T process or design changes.
= +25°C, controlled via design or process parameters and not directly tested. Characterized upon initial design and at major
A
AC Electrical Specifications V
PARAMETER SYMBOL
CLKIN Clock Period t CLKIN High t CLKIN Low t PROCCLK Period t PROCCLK High t PROCCLK Low t REFCLK Clock Frequency f REFCLK High t REFCLK Low t Setup Time GAINADJ(2:0), IN(13:0),
SYNCIN1 to CLKIN
= 5 ±5%, TA = 0°C to +70°C, Commercial; -40°C to +85°C, Industrial
CC
IH IL
IHC
ILC OH
OL
I
CCSB
O
CCOP
IN
OUT
= 5 ±5%, TA = 0° to +70°C, Commercial (Note 7); -40°C to +85°C, Industrial (Note 7)
CC
ENI, COF, COFSYNC, and
VCC = 5.25V 2.0 - V VCC = 4.75V - 0.8 V VCC = 5.25V 3.0 - V VCC = 4.75V - 0.8 V IOH = -400μA, VCC = 4.75V 2.6 - V IOL = +2.0mA, VCC = 4.75V - 0.4 V VIN = VCC or GND, VCC = 5.25V -10 +10 μA VCC = 5.25V, Outputs Not Loaded - 500 μA VIN = VCC or GND, VCC = 5.25V -10 +10 μA CLK = PROCCLK = 52MHz, VIN = VCC or
GND,
= 5.25V, Outputs Not Loaded
V
CC
Freq = 1MHz, VCC open, all measurements are referenced to device ground
CCOP
CP CH
CL PCP PCH PCL RCP RCH RCL
t
DS
- 420 mA (Note 5)
- 8 pF (Note 6)
is 7mA/MHz.
65MHz
UNITSMIN MAX
15 - ns
6 - ns 6 - ns
18 - ns
7 - ns 7 - ns
- PROCCLK/2 Hz 7 - ns 7 - ns 7 - ns
58
FN4450.4
May 1, 2007
HSP50214B
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AC Electrical Specifications V
PARAMETER SYMBOL
Hold Time GAINADJ(2:0), IN(13:0), ENI, COF , COFSYNC, and SYNCIN1 from CLKIN
Setup Time AGCGNSEL, SOF, MCSYNCI, SOFSYNC, and SYNCIN2 to PROCCLK
Hold Time AGCGNSEL, SOF, MCSYNCI, SOFSYNC, and SYNCIN2 from PROCC
Setup Time, A(2:0) to Rising Edges of Setup Time, A(2:0) C(7:0) to Rising Edges of Hold Time, A(2:0) from Rising Edges of Hold Time, A(2:0) C(7:0) from Rising Edges of WR to CLKIN t
PROCCLK to AOUT(15:0), BOUT (15:0), SEROUTB,
PROCCLK to SYNCOUT t PROCCK to MCSYNCO t PROCCLK to SERCLK, SERSYNC Valid t WR High t WR Low t RD Low t Address Setup to Read Low t RD LOW to Data Valid t RD HIGH to Output Disable t
Output Enable Time t Output Enable Time - FIFO Read Mode t Output Disable Time t
Output Rise, Fall Time t
NOTES:
7. AC tests performed with C Test V
8. Controlled via design or process parameters
9. Setup time required to ensure action initiated by
LK
INTRRP
= 3.0V, V
IH
= 40pF, IOL = 2mA, and IOH = -400μA. Input reference level for CLK is 2.0V, all other inputs 1.5V .
L
= 4.0V, VIL = 0V.
IHC
= 5 ±5%, TA = 0° to +70°C, Commercial (Note 7); -40°C to +85°C, Industrial (Note 7) (Continued)
CC
WR t
WR t
WR t
WR t
DATARDY, SEROUTA,
DO_SYNCO
and not directly tested. Characterized upon initial design and at major process or design changes.
WR will be seen by a particular CLKIN.
t
DH
t
DSS
t
DHS
WSA WSC WHA WHC
WC
t
DO_OUT
DO_SYNCI
DOS WRH WRL
RL
AS RDO ROD
OE
OEBL
OD
RF
65MHz
UNITSMIN MAX
0 - ns
7 - ns
0 - ns
8 - ns
10 - ns
2 - ns 0 - ns
14 - ns
(Note 9)
- 8 ns
- 8 ns
- 6 ns
- 12 ns
15 - ns
8 - ns
20 - ns
- 3 ns
- 18 ns
- 10 ns (Note 8)
- 6 ns
- 15 ns
- 8 ns (Note 8)
- 3 ns (Note 8)
59
FN4450.4
May 1, 2007
AC Test Load Circuit
www.BDTIC.com/Intersil
HSP50214B
NOTE: Test head capacitance.
Waveforms
WR
C(0-7), A(0-2)
DUT
SWITCH S1 OPEN FOR I
t
WRL
t
WSAtWHA
t
WSCtWHC
t
WRH
CCSB
C
(NOTE)
L
AND I
S
1
CCOP
t
RDO
±
1.5V I
t
AS
I
OH
EQUIVALENT CIRCUIT
RD
A(2-0)
C(0-7)
OL
t
RL
t
ROD
FIGURE 49. TIMING RELATIVE TO WR FIGURE 50. TIMING RELATIVE TO RD
t
CP
t
RF
2.0V
0.8V
t
CL
CLKIN
t
IN(13:0), COF
GAINADJ(2:0), ENI,
t
RF
COFSYNC, SYNCIN1
WR
DS
t
WC
t
CH
t
DH
FIGURE 51. OUTPUT RISE AND FALL TIMES FIGURE 52. TIMING RELATIVE TO CLKIN
60
FN4450.4
May 1, 2007
Waveforms
www.BDTIC.com/Intersil
HSP50214B
PROCCLK
t
PCL
t
PCP
t
PCH
, OEAL,
OEAH
OEBH
, OEBL
t
OUTA(15:8), OUTA(7:0), OUTB(15:8), OUTB(7:0)
FIGURE 53. OUTPUT ENABLE/DISABLE FIGURE 54. TIMING RELATIVE TO PROCCLK
t
OE
OEBL
1.5V
1.7V
1.3V
t
RCL
1.5V
t
OD
t
RCP
t
RCH
FIGURE 55. REFCLK
AGCGNSEL,
MCSYNC1
SOF, SOFSYNC,
SYNCIN2
BOUT(15:0), DATARDY
SYNCOUT, SEROUTA,
AOUT(15:0),
INTRRP, MCSYNC0,
SEROUTB
SERSYNC
f
RCP =
2 t
t
RCP Š
t
RCP
,
I
RCP
t
DSS
t
DHS
t
DO_ OUT, tDO _ MCSYNCO,
t
DO_ SYNCO
t
DOS
61
FN4450.4
May 1, 2007
HSP50214B
www.BDTIC.com/Intersil
Metric Plastic Quad Flatpack Packages (MQFP/PQFP)
E
E1
0.40
0.016
0o MIN
0o-7
-H-
-A-
o
MIN
D
D1
-D-
Q120.28x28 (JEDEC MO-108DA-1 ISSUE A)
120 LEAD METRIC PLASTIC QUAD FLATPACK PACKAGE
INCHES MILLIMETERS
SYMBOL
NOTESMIN MAX MIN MAX
A - 0.160 - 4.07 -
A1 0.010 - 0.25 - -
-B-
A2 0.125 0.144 3.17 3.67 -
B 0.012 0.018 0.30 0.45 6
B1 0.012 0.016 0.30 0.40 -
D 1.219 1.238 30.95 31.45 3
D1 1.098 1.106 27.90 28.10 4, 5
E 1.219 1.238 30.95 31.45 3
e
PIN 1
E1 1.098 1.106 27.90 28.10 4, 5
L 0.026 0.037 0.65 0.95 -
N 120 120 7
e 0.032 BSC 0.80 BSC -
5o-16
A2
SEATING
PLANE
A
0.10
o
A1
0.20
0.008
A-B SD SCM
0.004
-C-
B
B1
NOTES:
1. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact.
2. All dimensions and tolerances per ANSI Y14.5M-1982.
3. Dimensions D and E to be determined at seating plane .
4. Dimensions D1 and E1 to be determined at datum plane
-H-
.
5. Dimensions D1 and E1 do not include mold protrusion.
Rev. 0 1/94
-C-
Allowable protrusion is 0.25mm (0.010 inch) per side.
0.13/0.17
o
L
5o-16
0.005/0.007
BASE METAL
WITH PLATING
0.13/0.23
0.005/0.009
6. Dimension B does not include dambar protrusion. Allowable dambar protrusion shall be 0.08mm (0.003 inch) total.
7. “N” is the number of terminal positions.
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implic atio n or other wise u nde r any p a tent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
62
FN4450.4
May 1, 2007
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