Philips saa7283 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

SAA7283

Terrestrial Digital Sound Decoder (TDSD3)

Preliminary speciﬁcation File under Integrated Circuits, IC02

1996 Oct 24

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3)

FEATURES

• Single-chip solution including FM and vision filters, analog demodulator and audio switching

• Dual standard with automatic selection between PAL system I and BGH including French NICAM L system)

• Single low-radiation crystal oscillator for improved EMC

• Stereo bitstream audio DACs

• Programmable attenuator for matching levels of NICAM

and FM audio sources at the output of the device

• Full EBU NICAM 728 specification demodulation and decoding

• Digital Audio Interface conforming with EBU/IEC 958

• Automatic mute function which switches from NICAM to

FM sound when NICAM fails

• Compatible with either single-ended or differential DQPSK input signals

• Microcomputer controlled via I specification).

APPLICATIONS

• Television receivers

• Video cassette recorders.

GENERAL DESCRIPTION

The SAA7283 is a NICAM receiver solution, developing the well established high quality Terrestrial Digital Sound decoder family from Philips Semiconductors.

This innovative IC with analog front-end, offers more impressive features and flexibility with minimum external circuitry.

C-bus (up to 400 kHz

SAA7283

The SAA7283 takes, as input, a second IF (intercarrier) Terrestrial TV PAL signal, and performs all the Differential Quadrature Phase Shift Keying (DQPSK) demodulation, digital decoding and digital-to-analog conversion necessary to produce a complete NICAM receiver on a single integrated circuit.

The demodulator function includes integrated baseband filters for pulse shaping and unwanted signal rejection, automatic gain control, a low jitter integrated VCO, digital monostable for precise data sampling points and a multi-standard controller to enable automatic locking to either a PAL system I or PAL system BGH input signal (including French NICAM L system).

The decoder function performs the descrambling, de-interleaving and reformatting operations required to recover the original data words.

The data words are processed through a stereo digital filter, digital de-emphasis network, second order noise shaper and 256 times oversampling Bitstream audio DAC. The SAA7283 then provides a switching output buffer for selecting between FM, NICAM and daisy-chain inputs, and a programmable level attenuation matrix for matching levels of the FM and NICAM audio sources at the output of the device. An additional feature is the inclusion of a Digital Audio Interface (DAI) output IEC 958, which may be disabled if required.

ORDERING INFORMATION

TYPE

NUMBER

SAA7283ZP SDIP52 plastic shrink dual in-line package; 52 leads (600 mil) SOT247-1 SAA7283GP QFP64 plastic quad ﬂat package; 64 leads (lead length 1.95 mm);

1996 Oct 24 2

NAME DESCRIPTION VERSION

body 14 × 20 × 2.8 mm

PACKAGE

SOT319-2

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

QUICK REFERENCE DATA

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

clk

amb

supply voltage 4.5 5.0 5.5 V supply current − 205 − mA clock frequency − 8.192 − MHz operating ambient temperature −20 +25 +70 °C

1996 Oct 24 3

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

BLOCK DIAGRAM

handbook, full pagewidth

DDF1

SSF1

COFF CEYE

DDF2

SSF2

REMO

REMVE

REF

ROF

RCF

CLKLPF

DATAOUT

DATAIN

XTAL

OSC

SSX

SDA

SCL

ADSEL

DQPSK MIXREF

25 23

30 31

38 39

17 16

36 35

37 41

46 45

42 43

44 54

53 55

QUADRATURE MIXERS, BASEBAND FILTERS

CARRIER LOOP

PHASE DETECTOR

AND DATA SLICERS

RECOVERY

CRYSTAL

OSCILLATOR

29 28

AGC GAIN STAGE

COSINE

BITRATE

CLOCK

I C

AND

SINE

AGC

CONTROLLER

CARRIER LOOP

QUADRATURE

VCO

NICAM 728 DECODER

AND

DEVICE CONTROLLER

SOFF

SEYE

PKDET

VCONT

VCLK

PCLK

RESET

PORT2

MUTE

PORM

PORA

DOBM

SSDAC

(1) Represents controller bus.

DDD

SSD

FML

EXTL

DDA

SSA

ROA

RCA

SAA7283GP

49 48

12 13

61 62 7 63

DAI

NOISE SHAPER

(LEFT CHANNEL)

BITSTREAM DAC (LEFT CHANNEL)

OUTPUT

SWITCHES

AND

BUFFER

(LEFT CHANNEL)

11 4

OPL

DIGITAL FILTER, GAIN,

J17 DE-EMPHASIS

NOISE SHAPER

(RIGHT CHANNEL)

BITSTREAM DAC

(RIGHT CHANNEL)

(1)

OUTPUT

SWITCHES

AND

BUFFER

(RIGHT CHANNEL)

OPR

MGB464

FMR

EXTR

Fig.1 Block diagram (QFP64).

1996 Oct 24 4

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

PINNING

SYMBOL

SDIP52 QFP64

(1)

DESCRIPTION

MUTE 1 57 active LOW mute input; function deﬁned by MUTEDEF (control bit in the

I2C-bus register)

DOBM 2 59 digital audio interface output that can be 3-stated via I V V V

DDA SSA RCA

3 61 analog supply voltage for the audio channels 4 62 analog ground connection for the audio channels 5 63 internal audio reference voltage buffer (high-impedance node)

C-bus

EXTR 6 2 external analog input to the right audio channel FMR 7 3 FM sound input to the right audio channel OPR 8 4 analog output from the right audio channel n.c. 9 and 10 9 and 10 not connected; left open-circuit in application V

ROA

SSDAC

11 7 internal audio reference voltage buffer output

12 8 quiet ground connection to DACs n.c. 13 and 14 − not connected; left open-circuit in application OPL 15 11 analog output from the left audio channel FML 16 12 FM sound input to the left audio channel EXTL 17 13 external analog input to the left audio channel PORM 18 14 active LOW power-on reset mute input; mute cleared by setting silence bit

HIGH in I2C-bus (internal pull-up) PORA 19 15 power-on reset audio select input (internal pull-up) REMVE 20 16 carrier loop-ﬁlter connection REMO 21 17 carrier loop-ﬁlter output SEYE 22 21 sine channel eye pattern output for monitoring SOFF 23 22 sine channel offset compensator capacitor output V

SSF1

24 23 demodulator ground connection 1 VCLK 25 24 carrier loop VCO clock output for monitoring V

DDF1

26 25 demodulator supply voltage 1 VCONT 27 27 carrier loop VCO control voltage input MIXREF 28 28 mixer voltage reference or input when using differential DQPSK signal DQPSK 29 29 DQPSK input signal COFF 30 30 cosine channel offset compensator capacitor output CEYE 31 31 cosine channel eye pattern output for monitoring PKDET 32 34 AGC peak detector storage capacitor output V I

REF

V V V

ROF

RCF DDF2 SSF2

33 35 internal demodulator reference voltage buffered output

34 36 internal demodulator reference current output

35 37 internal demodulator reference voltage unbuffered output

36 38 demodulator supply voltage 2

37 39 demodulator ground connection 2 n.c. 38 40 not connected; left open-circuit in application CLKLPF 39 41 clock loop-phase comparator output

1996 Oct 24 5

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

SYMBOL

SDIP52 QFP64

(1)

DESCRIPTION

XTAL 40 42 8.192 MHz crystal oscillator input OSC 41 43 8.192 MHz crystal oscillator output

SSX

42 44 crystal oscillator ground connection DATAIN 43 45 serial data input at 728 kbits/s to decoder V

SSD

44 48 digital ground connection PCLK 45 47 728 kHz output clock to DQPSK demodulator V

DDD

46 49 digital supply voltage RESET 47 50 active LOW power-on reset input DATAOUT 48 46 serial data output at 728 kbits/s from DQPSK demodulator

SCL 49 53 serial clock input for I SDA 50 54 serial data input/output for I ADSEL 51 55 input that deﬁnes I PORT2 52 56 output that is directly controlled from Port 2 bit in I

C-bus

C-bus address bit 0 (internal pull-up)

C-bus

Note

1. Pins 1, 5, 6, 18, 19, 20, 26, 32, 33, 51, 52, 58, 60 and 64 are not connected; left open-circuit in application.

1996 Oct 24 6

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

handbook, halfpage

SSDAC

REMVE

MUTE

DDA

SSA

RCA

EXTR

FMR

OPR

n.c.

ROA

n.c.

13 40

n.c.

OPL

FML

EXTL

17 18

PORM PORA

19 20

SAA7283ZP

52 51 50 49 48 47 46 45 44 43 42 41

39 38 37 36 35

34 33

PORT2 ADSELDOBM SDA SCL DATAOUT RESET

DDD

PCLK V

SSD DATAIN V

SSX OSC

XTAL

CLKLPF n.c. V

SSF2 V

DDF2 V

RCF I

REF

ROF PKDETREMO

22 23

SSF1

DDF1

Fig.2 Pin configuration for SOT247.

1996 Oct 24 7

MGB463

30 29 28 27

CEYESEYE COFFSOFF DQPSK MIXREFVCLK VCONT

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

handbook, full pagewidth

EXTR

SSDAC

EXTL PORM PORA

REMVE

REMO

n.c.

FMR OPR

n.c. n.c.

ROA

n.c.

n.c. OPL FML

n.c.

SSA

RCA

n.c.

63 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19

DDA

n.c. 60

DOBM 59

n.c.

MUTE

SAA7283GP

PORT2 56

ADSEL

SDA 54

SCL

n.c.

51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

n.c.

RESET V

DDD

SSD

PCLK DATAOUT DATAIN

SSX

OSC XTAL CLKLPF

n.c. V

SSF2

DDF2

RCF

REF

ROF

PKDET

n.c.

SEYE

SOFF

SSF1

VCLK

DDF1

Fig.3 Pin configuration for SOT319.

1996 Oct 24 8

n.c.

VCONT

DQPSK

MIXREF

COFF

CEYE

n.c.

MGB462

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

FUNCTIONAL DESCRIPTION DQPSK demodulation

UADRATURE MIXERS, BASEBAND FILTERS AND AUTOMATIC

GAIN CONTROL

(AGC)

The DQPSK signal is fed into two differential input mixers, where it is mixed with quadrature phases generated by the carrier-loop quadrature VCO. The quadrature signals modulated onto the NICAM carrier are thus recovered.

The mixers can be driven by either a single-ended or differential source. In single-ended mode, the device is driven directly from the sound IF down-converter into the DQPSK input pin, with the MIXREF pin decoupled. In differential mode, the signal is applied between the DQPSK and MIXREF pins.

The outputs from the mixers are then fed into a pulse-shaping filter, and FM/vision filter stage which filters out all interference components, including AM carrier for French NICAM L system. The signal from the filtering stages is then fed into the AGC, which ensures that the phase comparator gain remains constant, irrespective of the input signal level. This is important to maintain the stability of Costas loop PLL.

CONTROLLER

AGC The AGC controller monitors the I and Q channel signals

at the input to the carrier loop-phase comparator and generates a reference voltage to set the AGC output level.

YE BUFFER

A differential to the single-ended converter provides the baseband signal as an output at the pins CEYE and SEYE for the I and Q channels respectively for eye-height monitoring.

IT RATE CLOCK RECOVERY

B The I and Q channels are processed using edge detectors

and monostables, which generate a signal with a coherent component at the data symbol rate. The outputs from the I and Q channel monostables are each compared with the clock derived from PCLK (364 kHz nominal), the resultant output is used to derive a 3-state control signal used to control two current sources at the CLKLPF output. This error signal is loop filtered and used to control the master clock oscillator. The bit rate clock, PCLK, and symbol clock are derived from the master clock.

NICAM 728 decoding

ECODING FUNCTIONS

The device performs all decoding functions in accordance with the EBU NICAM 728 specification. After locking to the frame alignment word, the data is de-scrambled by application of the defined pseudo random binary sequence, and the device synchronizes to the periodic frame flag bit C0.

The relevant control information and scale factor word is extracted, and with the integrated RAM the data is de-interleaved and the scale factor word is extracted, and expanded to 14 bits. Parity checking on the eleventh bit of each sample word is carried out to reveal any sound sample errors, which if detected are flagged, with the last good sample being held.

Automatic muting

Enable when AMDIS = LOW. The I

C-bus section has two registers which define an upper and lower limit for the automatic muting function. When the number of errors within a 128 ms period exceeds the number stored in the upper error limit register, then the automatic muting will switch the device output to the FM input, (dependent on the relevant control bits in the I2C-bus) and mute (set to zero) the data input to the filter (in that order). When the error count in a 128 ms period is less than the value stored in the lower error limit register then the data into the filter is uninterrupted, and the device output is switched back to the DAC (dependent on the value of the relevant control bits in the I2C-bus). During the muting operation the open-drain pin MUTE is pulled LOW and the AM bit in the status-byte is set HIGH. Figure 4 shows the dependency of the automatic muting function on error_count, RSSF, C4OV, output state and application mode. The automatic muting function, if enabled, will override user mute via the MUTE pin/bit.

When the transmission is DATA format or currently undefined format (C3 = logic 1) the device will automatically switch to the FM inputs regardless of RSSF/C4OV states, and whether the automatic muting function AMDIS is enabled or disabled.

1996 Oct 24 9

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

User mute

The error counter is an 8-bit counter which locks at count 255. The counter is reset and its output sent to the I2C-bus every 128 ms. This enables the user to interrogate the number of errors occurring within a 128 ms period. The user can then mute the device by pulling pin MUTE LOW (this function is also provided by the MUTE bit in the I2C-bus) or setting SILENCE bit LOW in I2C-bus to switch input of audio switching buffers to analog ground.

Switching buffers

The analog switches select between the output of the DACs, the FM input and an external input (EXT). Switching is controlled by bits in the I

C-bus and internal switching function. The external analog inputs should be ≤1.1 V (RMS) at the input pin, and the output buffers have a voltage drive of 1 V (RMS).

NICAM/FM audio level matching

Differing audio headroom and alignment levels occur between systems I and BGH, due to the differing systems and broadcast standards. In order to match the NICAM and FM audio output levels without requiring application changes, the device will automatically switch in 4.6 dB attenuation network in the NICAM path for system BGH (this can be disabled by setting the NICLEV bit LOW in

C-bus). A programmable attenuation network in the FM

I path only, controlled by bits in I2C-bus, provides additional flexibility for user to match FM and NICAM audio levels (see Table 9).

Power-on reset state

Two pins control the initial set-up of the device during power-on reset.

PORA (Power-On Reset Audio)

When pulled LOW the device will be configured with a 12 dB gain in the oversampling filter and the

C4OV bit in the I2C-bus will be set HIGH. This pin when HIGH will configure the device with a 6 dB gain in the oversampling filter and will set C4OV bit in the I2C-bus LOW.

PORM (Power-On Reset Mute)

This pin when LOW will mute the output of the device at power-on by setting the SILENCE bit in the I2C-bus LOW. To put the device back into a normal mode of operation the SILENCE bit in the I2C-bus must be set HIGH.

1996 Oct 24 10

Philips Semiconductors Preliminary speciﬁcation

Terrestrial Digital Sound Decoder (TDSD3) SAA7283

handbook, full pagewidth

ERROR_COUNT

ERROR_MAX

YES

RSSF = 1

EXT or FM INPUT

SWITCHED IN

SOUND APPLICATION

DUAL MONO

YES

MUTEB pin = HIGH

YES

MUTEB pin = LOW

DUAL MONO MODE

LEFT = RIGHT = M1

Output is

unchanged

AM bit = LOW

C4ov BIT = 0

YESYES

Output is

unchanged

AM bit = HIGH

SELECTED

YES

(1)

Output is

unchanged

AM bit = LOW

MUTEB pin = HIGH

When error_count is less than error_min, AM bit = LOW, MUTEB pin = HIGH

Output is

unchanged

AM bit = LOW

MUTEB pin = HIGH

MGB465

Output is switched

to FM input

AM bit = HIGH

MUTEB pin = LOW

(1) Indicating that a mute may occur when user returns to NICAM source.

When error_count is less than error_min, the output is switched back to NICAM and AM bit = LOW, MUTEB pin = HIGH

Fig.4 Flow diagram showing SAA7283 automatic muting function.

1996 Oct 24 11

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