Introduction to RF ................................................................................................................................... 6
RF power supply configuration .........................................................................................................9
General specifications of transceiver RH-47 ..............................................................................10
Introduction to RF Troubleshooting ................................................................................................ 11
RF test points .......................................................................................................................................13
Test points RF supply voltages.................................................................................................... 14
RF test points Mjoelner chamber............................................................................................... 15
RF test points VCO chamber........................................................................................................ 15
RF test points PA chamber........................................................................................................... 16
Test points BB area......................................................................................................................... 16
Troubleshooting for PLL synthesizer .............................................................................................37
Frequency lists .....................................................................................................................................39
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
Introduction to RF
The RF front-end is a dual-band direct conversion transceiver. Using direct conversion, no
intermediate frequencies are used for up- or down -conversions.
The VCO oscillates on the doubled respectively quadruplicated frequency of the wanted
RX or TX frequency, depending on the band used. The VCO frequency is divided by either
2 or 4 and fed to the mixers (down-conversion) or modulators (up-conversion). Up- or
down-conversion is done in one step, directly between RF frequency and base band. All
up- and down-conversion takes place in the RF ASIC named Mjoelner (N601).
Mjoelner RF ASIC also contains PLL and LNAs for all used bands. ADC control section is
included to power and/or control GSM850 TX buffer, detector and antenna switch. The
Mjoelner RF ASIC is controlled via a serial bus.
Mjoelner RF ASIC contains an integrated VCXO which uses an external 26 MHz Xtal. No
analogue AFC signal is needed. AFC is realized via the serial interface port of Mjoelner.
The UPP is supplied by the 26 MHz reference clock of Mjoelner.
The phone supports GPRS (General Packet Radio Service), meaning multi-slot operation.
This will not require special equipment or procedures in repair situations.
The following diagrams show the RF frequency scheme and the RF block diagram.
Nokia Customer Care7 - RF Description and Troubleshooting
RF power supply configuration
All power supplies for the RF Unit are generated in the UEM IC (D190). All RF supplies
can be checked either in Mjoelner or in BB chamber.
The power supply configuration used is shown in the block diagram below. Values of
voltages are given as nominal outputs of UEM. Currents are typical values.
Nokia Customer Care7 - RF Description and Troubleshooting
Introduction to RF Troubleshooting
This document shall provide instructions, how to check, repair and calibrate RH-47
phones. It is assumed, that the phones are disassembled and tested within a repair jig
MJ-21.
The following types of measurements have to be done for repair of the phone boards:
•RF measurements are made by using a Spectrum Analyzer together with a highfrequency probe (i.e. hp 85024A Note, that signal levels are not accurate ). Correct attenuation can be checked using a “good” phone board for example.
•LF (Low frequency) and DC measurements are made with an oscilloscope
together with a 10:1 probe.
•For receiver measurements a signal generator with frequencies up to 2000 MHz
is required. Most of the radio communication testers like CMD55 or CMU200 can
be used as signal generator. The signal generator is connected to the antenna
port using the repair jig MJ-21.
•Output level measurements of the transmitter are made with a power meter or a
calibrated spectrum analyser, which is connected to the antenna port using the
repair jig MJ-21.
Always make sure that the measurement set-up is calibrated when measuring RF parameters at the antenna port. Remember to include the correct losses of the module repair
jig and the connecting cable when realigning the phone.
Most RF semiconductors are static discharge sensitive. ESD protection must be taken
into account during repair (ground straps and ESD soldering irons).
Mjoelner RF ASIC is moisture sensitive. Therefore, Mjoelner RF ASIC must be pre-baked
prior to soldering.
Rx calibration done via Phoenix software is temperature sensitive because of calibration of the 26 MHz reference oscillator (VCXO). According to Mjoelner specification
ambient temperature has to be in a range from 22°C to 36°C.
Apart from key-components described in this document there are a lot of discrete components (resistors, inductors and capacitors) for which trouble shooting is done by
checking its proper soldering and complete assembly on the PWB. Capacitors and resistors can be checked by means of an LCR meter, but be aware in-circuit measurements
should be evaluated carefully.
In the following GSM850 will be used for the low band, and PCS or GSM1900 for the
high band.
Note: In this document there are example measurements being depicted with Phoenix Internal Service
Software A2003.42.1.48 pictures.
Nokia Customer Care7 - RF Description and Troubleshooting
1900 Rx SAW (Z603)4511325Murata
850 Tx SAW (Z701)4511317Murata
850 Rx SAW (Z604)4511323Murata
Antenna switch (Z601)LMZ01704510449Murata
Crystal (B601)TSX-8A-258504510337Toyocom
Tx Coupler (L801)LDC21836M19D-1854550197Murata
Tx850 buffer (V802)BFR949T-E63274210171Infineon
RF test points
The RF power supplies are generated in the UEM and can be measured either in the
Mjoelner chamber or in the base band chamber. On the drawing below small circles show
the locations of the test points.
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
the generator as instructed in the window. Take care for external cable and test
jig attenuation losses.
7Switch off the external RF signal as instructed in the next pop-up window.
8Press OK and read the SNR result.
The values should be:
GSM850> 20dB
GSM1900 > 18dB
Measuring front-end power levels using spectrum analyzer
Spectrum Analyzer (SA) level values depend on the probe type and should be validated
using a good sample. The levels that are given here are measured using an hp 85024A
probe.
1Start Phoenix Service Software and open FBUS connection:
SelectScan ProductCtrl-R
Wait until phone information is shown in the lower right corner of the screen.
Nokia Customer Care7 - RF Description and Troubleshooting
SelectBandGSM850 or GSM1900
Active unitRX
Operation modeContinuous
RX/TX Channel190 or 661
Please refer to the fault-finding chart and Appendix C for proper levels at different test
points.
Measuring analogue RX I/Q signals using oscilloscope
Measuring with an oscilloscope on “RXIINN” or “RXQINN” is recommended only if RSSI
reading does not provide enough information. There are dedicated test points for RX I
and Q signals. Apply an Input signal level of -80dBm.
1Start Phoenix Service Software and open FBUS connection:
SelectScan ProductCtrl-R
Wait until phone information is shown in the lower right corner of the screen.
2Set operating mode to local mode:
SelectMaintenanceAlt-M
TestingT
RF ControlsF
Wait until the RF Controls window is pops up.
3In the RF Controls window:
SelectBandGSM850 or GSM1900
Active unitRX
Operation modeContinuous
RX/TX Channel190 or 661
AGC14
Following picture should be displayed on an oscilloscope' s screen if the GSM850
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
receiver is working properly:
Receiver troubleshooting
The phone layout has dedicated test points for the analogue differential RX I and Q signals (RXIINP, RXIINN, RXQINP, RXQINN) from Mjoelner RF ASIC to UEM. The BB part is
used to measure those signals by means of RSSI reading. It is assumed that correct calibration of RSSI reading has been carried out in production.
RSSIreading [dBm] = 20log(U
Therefore, do not calibrate a defective phone before the phone error has been
found.
When a defective phone has been calibrated, a possible error in RX front-end might be
masked. In that case one can get a reasonable RSSI reading, although the front-end
shows excessive losses.
If you are not sure that incorrect re-calibration has been made, the following steps
should be done:
Nokia Customer Care7 - RF Description and Troubleshooting
2Check if SNR reading is OK.
Use an Oscilloscope to check levels of “RXIINN” and “RXQINN”.
Make sure that
Synthesiser
is working
Note: RF levels given in that chart are dependent on RF probe and m ust be v alidated with a known good sample
Apply -80dBm signal
from Generator
to Antenna Connector
phone: local, burst mode
GSM, PCS
RSSI reading
-80dBm
all bands
RX calibration
Calibration.
Rx chain
functional
= to be done in all 3 bands
?
within
limits
?
GSM, PCS
Apply -92dBm signal
No
Yes
from Generator
to Antenna Connector
phone: local, burst mode
SNR measurement
all bands
o.k.
?
Yes
No
Yes
= to be done in
defective band only
= to be done only once
(common for all bands)
No
wrong in both
Change signal level
to -60dBm
phone: local,
continous mode
Check
RxTx Switch
RSSI
and SN R
bands
?
SA
SA
Z601
Z601
Rx output
EGSMout
(850 &1900)
-76dBm
> -67dBm
?
No
Change
Z601
Yes
No
Yes
Check
SAW
Osci:
SA
RF-BB
Z601
serial
EGSMout
Interface
-76dBm
o.k.
?
No
BB Error
Check UPP
SA
SA
Z604,Z603
Z601
SAWout
EGSMout
both lines
-76dBm
>-72dBm
?
No
Change
Z604, Z603
Yes
Yes
EGSMout
Change
Mjolner
Check
Bias
C620, C632
Osci:
SA
RX I/Q
Z601
level
o.k.
-76dBm
?
No
Osci:
SA
LNA bias
Z601
(VR4)
EGSMout
=2.8V
-76dBm
?
Check
and
BB (UEM)
Yes
BB Error
Check UEM
Check
Bias
RX -BB bias
Yes
EGSMout
No
BB (UEM)
If RX and TX path seem to be faulty it has to be checked if the synthesizer is working. If
yes, then check the path from the antenna test pad J800 to the antenna switch Z601
(see RX troubleshooting "Check RXTX switch").
Osci:
SA
Z601
(VR4)
=2.8V
-76dBm
?
Check
C871
and
Check
Yes
LNA
No
Yes
Osci:
SA
LNA
Z601
base voltage
EGSMout
= 0.8V
-76dBm
?
No
Change
Mjoelner
Rx signal paths
The signal paths of the receiver are shown in following block diagram. Note that the diagram shows GSM850 receiver (above) and the GSM1900 receiver (below).
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
Figure 5: Rx signal paths
Rx
supply
filter
F
X
R
D
D
V
LNA
Bias
SAW
RX
GSM
TX
RX
Ant Switch
PCN
TX
2
RX850
RX1800
SAW
RX1900
INPL
LNA
INML
INPM
LNA
INMM
INPH
LNA
INMH
VANTL /
VANTM
2
VANTH
RF
Controls
RF
Controls
Pre-gain
Pre-gain
VDDDIG
VDDRXBB
222
2
1/2
BBAMP
BBAMP
1/4
B
B
X
R
D
D
V
BIQUAD
LPF1
LPF1
DCN1
DCN1
AGC
AGC
LPF2
BIQUAD
LPF2
DCN2
DCN2
VDDLO
Mjølner
VRX
RXIP
RXIM
RXQP
RXQM
VR6
Antenna switch (RX/TX Switch)
Signal path of RF: From the antenna-pad (J800) the RF signal is fed through the antenna
low pass filter (C743, L610, C748) to the antenna switch (Z601).
The antenna switch has the function of a diplexer which consists of two paths for
GSM850 and GSM1900. The GSM850 input signals pass the switch to the GSM_RX output. GSM1900 input signals pass to PCS_RX output. In receive mode both control signals
VC1 (VANTL) and VC2 (VANTH) have to be 0 V.
Signal paths:
GSM850: RX1-GSM output of the antenna switch Æ GSM850 SAW filter (Z604).
GSM1900: RX2-PCS output of the antenna switch Æ GSM1900 SAW filter (Z603).
The antenna switch including routed lines has following typical insertion losses:
GSM850: 1.3dB
GSM1900:1.6dB
RX front-end
The RX front-end includes two SAW filters for GSM850 (Z604) and GSM1900 (Z603).
They are matched to the corresponding LNA inputs of Mjoelner RF ASIC (N601) with differential matching circuits (LC-type). The SAW filters provide out-of-band blocking
immunity. The integrated LNAs provide the front-end gains. Each of the SAW filters has a
single-ended input and a balanced output.
Nokia Customer Care7 - RF Description and Troubleshooting
RX paths of Mjoelner RF ASIC
The balanced RX signal is amplified by the integrated LNA and the subsequent pre-gain
stage. After amplification the RX signal is down-converted.
The RX paths of Mjoelner RF ASIC consist of following sub units:
Separate LNAs for each of the two bands: GSM850 and GSM1900.
Two PRE-GAIN amplifiers, one for GSM850 and one for GSM1900.
Two passive I/Q mixers (MIX), one for GSM850 and one for GSM1900.
The BB signal paths consist of:
•Baseband amplifiers (BBAMP1). These amplifiers implement the initial channel
filtering.
•Low pass filters (LPF1).
•DC compensation / AGC amplifiers (DCN1). These amplifiers implement gain steps
from 0dB to 24dB in 6dB steps.
•Attenuators (AGC). They implement gain steps from -48dB to 0dB in 6dB steps,
yielding a total gain range of 72dB together with DCN1.
•Bi-quad filters (LPF2).
•DC compensation amplifiers (DCN2).
The differential base band outputs are internally DC-coupled and are connected directly
to the ADC inputs of the UEM-ASIC. The common mode level is set equal to the VBEXT
reference voltage.
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
Transmitter
General instructions for TX troubleshooting
Connect an RF cable between the test jig and the measurement equipment (GSM test
equipment, power meter, spectrum analyzer, or similar).
Make use of an adequate attenuator at the input of your measurement equipment (10dB
to 20dB are recommended for a spectrum analyzer or a power meter). Assure not to
overload or destroy the equipment.
Connect the phone to a PC with DAU-9S cable (RS232) and Phoenix dongle PKD-1CS.
Provide the phone with power supply (3.6V).
Start Phoenix Service Software and open FBUS connection:
SelectScan ProductCtrl-R
and wait until phone information is shown in the lower right corner of the screen.
Follow the instructions in the chapters below.
TX signal paths
For easy error tracking it is important to know the signal paths of the transmitter. The
components are grouped in blocks and shown in the diagrams below.
Note that the diagram shows both GSM850 transmitter (below) and PCS1900 transmitter (above).
Nokia Customer Care7 - RF Description and Troubleshooting
Figure 6: Transmitter signal paths
VANTL / VANTH
3
3
3
3
VB_DET
VB_DET
VB_DET
VB_DET
VTXLOL
VTXLOL
VTXLOL
VTXLOL
VTXLOH
VTXLOH
VTXLOH
VTXLOH
VTXBH
VTXBH
VTXBH
VTXBH
VTXBL
VTXBL
VTXBL
VTXBL
PCN/PCS
PCN/PCS
PCN/PCS
PCS
PA
PA
PA
PA
DET
DET
DET
DET
VBATTRF
VBATTRF
VBATTRF
VBATTRF
Buffer
Buffer
Buffer
Buffer
GSM850
GSM850
GSM850
GSM850
PCS
PCS
PCS
PCS
TX
TX
TX
TX
n
n
n
n
t
t
t
t
S
S
S
S
GSM
GSM
GSM
GSM
wit
wit
wit
wit
TX
TX
TX
TX
Dir. Coupler
Dir. Coupler
Dir. Coupler
Dir. Coupler
Balun
Balun
Balun
Balun
VTX
VTX
VTX
VTX
SAW
SAW
SAW
SAW
PW-
PW-
PW-
PWloop
loop
loop
loop
filter
filter
filter
filter
OUTHP
OUTHP
OUTHP
OUTHP
OUTHM
OUTHM
OUTHM
OUTHM
OUTLP
OUTLP
OUTLP
OUTLP
OUTLM
OUTLM
OUTLM
OUTLM
DET
DET
DET
DET
PLFB1
PLFB1
PLFB1
PLFB1
PLFB2
PLFB2
PLFB2
PLFB2
VPCH/VPCL
VPCH/VPCL
VPCH/VPCL
VPCH/VPCL
RF
RF
RF
RF
RF
RF
Controls
Controls
Controls
Controls
Controls
Controls
RF
RF
RF
RF
RF
RF
Controls
Controls
Controls
Controls
Controls
Controls
Open
Open
Open
Open
Open
Open
collector
collector
collector
collector
collector
collector
Open
Open
Open
Open
Open
Open
collector
collector
collector
collector
collector
collector
2
2
2
2
P
P
P
P
TXP
TXP
TXP
TXP
PWC
PWC
PWC
PWC
PWC
PWC
TXCTX
TXCTX
TXCTX
TXCTX
TXC
TXC
TXC
TXC
VDDDIG
VDDDIG
VDDDIG
VDDDIG
VDDDIG
VDDDIG
VDDRXBB
VDDRXBB
VDDRXBB
VDDRXBB
V
V
V
V
D
D
D
D
DT
DT
DT
DT
Supply
Supply
Supply
Supply
filter
filter
filter
filter
VT
VT
VT
VT
X
X
X
X
VR2
VR2
VR2
VR2
1/4
1/4
1/4
1/4
1/4
1/4
1/2
1/2
1/2
1/2
1/2
1/2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
TX
TX
TX
TXQ
Q
Q
Q
P/
P/
P/
P/
TX
TX
TX
TX
Q
Q
Q
Q
2
2
2
2
2
2
2
2
2
2
2
2
Mjølner
Mjølner
Mjølner
Mjølner
2
2
2
2
TX
TX
TX
TX
IP/
IP/
IP/
IP/
TX
TX
TX
TX
IM
IM
IM
IM
The balanced TX IQ baseband signals (TXIOUTP, TXIOUTN, TXQOUTP, TXQOUTN) are provided by the baseband and are fed to the Mjoelner RF ASIC. The TX path of the Mjoelner
RF ASIC includes mainly two RF modulators for up-conversion of the baseband signals,
one for GSM850 and one for GSM1900. The baseband signal is up-converted with the LO
signal corresponding to the wanted TX channel. Both RF-TX outputs (850MHz and
1900MHz) of the Mjoelner RF ASIC are delivering balanced signals.
The GSM850 output signal of the Mjoelner RF ASIC is fed through the GSM TX SAW
filter (balanced to single ended) and the GSM850 MHz buffer to the GSM input of the
power amplifier (PA).
The GSM1900 output signal of the Mjoelner RF ASIC is fed through the TX balun (T701) (balanced to single ended) and a 2dB pad to the GSM1900 input of the power amplifier
(PA).
The Dual Band PA has a maximum output power of approx. 35dBm at 850MHz and
33dBm at 1900MHz. DC-power supply is delivered directly from the battery through an
RF choke L850.
The RF output power is controlled by the power control loop. From the output of the PA
both signals are fed through a dual directional coupler (one of the power control loop
components) to the antenna switch.
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7 - RF Description and TroubleshootingNokia Customer Care
Antenna switch (TX/RX switch)
The antenna switch operates as a diplexer for the RX and TX signals. Moreover, it suppresses the TX harmonics generated by the PA. The antenna switch is controlled by the
Mjoelner RF ASIC using the control signals VC1 and VC2.
The following table shows the possible different states.
Table 1: Logic table for the antenna switching states
VC1 [Volt]VC2 [Volt]GSM RXPCS RXGSM TXPCS TX
00XX
02.7X
2.70X
GSM850 transmitter
General instructions for GSM850 TX troubleshooting
Start the preparations as described in chapter General instructions for TX troubleshooting “General instructions for TX troubleshooting”.
1Set operating mode to local mode.
SelectMaintenanceTestingRF Controls
Wait until the RF Controls window pops up.
2In the RF Controls window:
SelectBandGSM850
Active unitTX
Operation modeBurst
RX/TX Channel190
TX Power Level10
TX Data TypeRandom
Nokia Customer Care7 - RF Description and Troubleshooting
The setup should now look like this:
Now the measurement equipment should detect the following output signal of the
phone:
P
= +23 ± 1dBm @ 836.6 MHz
out
If this is not the case, then go to the next chapter for troubleshooting.
Troubleshooting for GSM850 transmitter
In the following troubleshooting chart, the TXP signal is used as a trigger-signal. For this
purpose a TXP test point is provided on the PWB, refer to figure RF test points in the
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
Troubleshooting for GSM1900 transmitter
In the following troubleshooting chart, the TXP signal is used as a trigger-signal. For this
purpose a TXP test point is provided on the PWB, refer to RF test points in the Mjoelner chamber.
Nokia Customer Care7 - RF Description and Troubleshooting
Synthesizer
One PLL synthesizer is generating all the required frequencies of both bands for Rx and
Tx. The VCO frequency is divided by 2 or by 4 in Mjoelner depending on the active band.
General instructions for synthesizer troubleshooting
Connect the phone to a PC with DAU-9S cable (RS232). The PC must have Phoenix Service Software installed and a PKD-1CS dongle is required.
Follow the instructions in the chapters below.
Checking synthesizer operation
1Start Phoenix Service Software and open FBUS connection:
SelectScan ProductCtrl-R
Wait until phone information is shown in the lower right corner of the screen.
2Set operating mode to local mode.
3Start RF Control window:
SelectMaintenanceAlt-M
TuningT
RF ControlsF
Wait until the RF Controls window pops up.
4Set the synthesizer to the following mode:
SelectBandPCS1900
Active unitRX
Operation modeContinuous
RX/TX Channel661
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
The setup should now look like this:
The frequency of 3920MHz at the output of the VCO (G701) has to be measured with an
RF probe and a spectrum analyzer.
The tuning voltage can be easily measured at the VC input of the VCO (C712) The tuning
voltage should be 3.2 .. 3.4V at f
VCO
typically 240MHz/V.
If this is not the case, then go to chapter Troubleshooting for PLL synthesizer.
26 MHz reference oscillator (VCXO)
The VCXO is integrated in the Mjoelner RF-ASIC (N601). The only external component is
the 26MHz crystal (B601).
The reference oscillator has two functions:
•Reference frequency for the PLL synthesizer.
•System clock for BB (RFClk = 26 MHz).
For an error free initial synchronization, the 26MHz frequency of the VCXO must be
accurate enough. Therefore, a VCXO-calibration value is written via the serial Bus into
the RefOSCCAL register of Mjoelner and an additional bit in the RefOSCCntl register of
the Mjoelner. That is necessary for the rough calibration of the VCXO.
= 3920.0MHz. The tuning sensitivity of the VCO is
The VCXO is fine tuned by programming the AFC value via the serial bus of Mjoelner. The
Nokia Customer Care7 - RF Description and Troubleshooting
necessary AFC value is written into the RefOSCAFC register in Mjoelner.
VCO
The VCO is able to generate frequencies in the range of 3296.8 MHz to 3979.6 MHz
when the PLL is working properly. The frequency of the VCO signal is divided by 2 or by 4
in Mjoelner RF-ASIC. This allows the generation of all the frequencies in the GSM850
and the GSM1900 bands, both RX and TX.
The output frequency of the VCO is controlled by a DC voltage (VC) of the PLL loop filter.
The valid range of VC is 0.7V– 3.8V when the PLL is in steady state. The typical tuning
sensitivity is 240MHz/V. Even if the PLL is not working properly (VC outside the valid
range) a frequency at the output of the VCO can be detected between 3GHz and 4 GHz
(if the VCO itself is OK).
Troubleshooting for PLL synthesizer
It is important to note that the power supply of the VCXO (VR3) is only switched off in
the so-called ‘Deep Sleep Mode’ and the power supply of the VCO G701 (VR7) is switched
off in so-called ‘Sleep Mode’.
RH-47Company Confidential
7 - RF Description and TroubleshootingNokia Customer Care
DC Supply Current Check
For a quick check of DC power supplies refer to the diagram below. Voltage drops are
measured at the respective resistors pads. Note, that not all currents can be checked in
such a way, see the marking <na> (not applicable) in the diagram.
Nokia Customer Care7 - RF Description and Troubleshooting
Phoenix Tunings after Repairs
The following tunings have to be performed after repairs:
•Repairs in the TX part require "TX Power Level Tuning".
•When component replacements around the modulator area (RF path from UEM
via RF ASIC to RF PA) have been done, "TX IQ Tuning" is additionally required.
•In RX general repairs, front-end always require "RX Calibration" and “Rx Band
Filter Calibration” for all three bands.
•Repairs in the PLL circuit always require "RX Calibration" of the low band.
•If the RF ASIC is replaced, all calibrations mentioned above have to be done.
Refer to Chapter 3, Service Software Instructions, for instructions on the above-mentioned tunings.
Nokia Customer Care7 - RF Description and Troubleshooting
APPENDIX D: Calibration of the DA-17/JXS-2 jig, Autotuning and BT Testing
Requirements
•U.S. AMS requirement is to align/check the phone completely assembled (in addition to the alignment in the MJ-21 repair jig which is still possible).
•RF couplers must be used because there is no RF connector on RH-47.
•DUT must be placed in a shielded box (JXS-2) to achieve accuracy and in order to
avoid external interference.
•First Symbian OS phone to support “RF autotuning“.
•Normal to Local mode switching must be done manually as Symbian OS does not
support SW switching.
Calibration Problems
•PA (Hitachi PF 08130B-TB) O/P power is very sensitive to LOAD variations.
•GSM Dual band antenna match is only -5 dB on GSM850 TX band.
•Battery BL-6C is part of the antenna (GSM850) – but in the DA-17 jig, the battery is removed -> antenna resonance is shifted!
•Coupler is self-resonant and must be very close to the GSM antenna -> Further
resonance shift of GSM antenna.
=> very careful “active calibration” method is needed
Active calibration: basic idea
•DA-17/JXS-2 system is seen as a “black box”.
•Calibration of the “black box” can be done with any functional phone sample and
MJ-21 repair jig.
•Once the calibration has been done, no changes inside the black box are allowed
(except removing and fitting the phone).
•All calibration data from the black box is based on conducted measurement with
MJ-21.
•The best accuracy is achieved for the highest TX power level (PCL0 / PCL5).
Calibration procedure setup MJ-21
The initial setup is shown below. The phone is disassembled and the engine PWB is
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MJ-21 example figures
Example valueParameter
Exam ple valueParam eter
32.5dBmM J21_TX_850
32.5dBmM J21_TX_850
29.5dBmM J21_TX_1900
29.5dBmM J21_TX_1900
-61.5dBmM J21_R X_850_LOW
-61.5dBmM J21_R X_850_LOW
-60.7dBmM J21_R X_850_M ID
-60.7dBmM J21_R X_850_M ID
-60.7dBmM J21_R X_850_H IGH
-60.7dBmM J21_R X_850_H IGH
-6 1 d B mM J21_R X_1900_LOW
-6 1 d B mM J21_R X_1900_LOW
-60.6dBmM J21_R X_1900_M ID
-60.6dBmM J21_R X_1900_M ID
-60.5dBmM J21_R X_1900_HIGH
-60.5dBmM J21_R X_1900_HIGH
Before assembling the phone and setting up the shielded box JXS-2 with DA-17, the
parameters must be known.
JXS-2 / DA-17 “blackbox” setup
•The assembled phone is placed on the DA-17 test adapter. This must be fitted
with the AQ_AMSCPL_01 directional coupler assembly and the Bluetooth directional coupler assembly.
•A 3 dB attenuator is connected to the SMA-socket of the GSM coupler. A short
coaxial cable is connected to the SMA-feedthrough on the backside of JXS-2.
•A ferrite bead is placed on the coaxial cable at a distance of 4cm from the SMA
connector at the GSM coupler.
Data acquisition JXS-2 / DA-17
The switch on the left side of DA-17 must be set to Local mode (lower position).
The supply voltage VCC=3.8V is fed through the JBV-1 adapter.
The shielded box has to be closed for all RF measurements.
The same parameters must be measured as for MJ-21. Follow the instructions given earlier.
•TX Power on MID channel (GSM850 PCL=5, GSM1900 PCL=0)
Nokia Customer Care7 - RF Description and Troubleshooting
•RX RSSI level on LOW channel (GSM850, GSM1900)
•RX RSSI level on MID channel (GSM850, GSM1900)
•RX RSSI level on HIGH channel (GSM850, GSM1900)
The cable attenuation values (incl. power splitter when used) must be taken into account
in the measurement process. However, disregard the attenuation of the “black box”
because this is the value to be determined.
DA-17/JXS-2 example figures
After the measurement in the “black box”, the following parameters are determined (typical values listed below).
Example valueParameter
Exam ple valueParam eter
24.5dBmDA17_TX_850
24.5dBmDA17_TX_850
22.5dBmDA17_TX_1900
22.5dBmDA17_TX_1900
-70.5dBmDA17_RX_850_LOW
-70.5dBmDA17_RX_850_LOW
-69.5dBmDA17_RX_850_M ID
-69.5dBmDA17_RX_850_M ID
-69.6dBmDA17_RX_850_HIGH
-69.6dBmDA17_RX_850_HIGH
-6 8 d B mDA17_RX_1900_LOW
-6 8 d B mDA17_RX_1900_LOW
-6 8 d B mDA17_RX_1900_M ID
-6 8 d B mDA17_RX_1900_M ID
-68.3dBmDA17_RX_1900_HIGH
-68.3dBmDA17_RX_1900_HIGH
The calibration factor needed for the RF autotuning in DA-17/JXS-2 is calculated by subtracting the DA-17 value from the MJ-21 value. This must be done for each of the eight
values.
Setting cable loss for Auto-Tuning
Phoenix allows you to set separate loss values at different frequencies for cables and the
jig.
Procedure:
1From the Tuning menu, choose Set Loss.
2Enter the cable losses (incl. Power splitter if used) for GSM850 at 824 and 894