Loading...Nokia Customer Care
RH-19/RH-50 Series Cellular Phones
7 - RF Description and
Troubleshooting
Issue 3 05/2004 |
2004 Nokia Corporation. |
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Company Confidential |
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RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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Page 2 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
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Company Confidential |
RH-19/RH-50 |
Nokia Customer Care |
7 - RF Description and Troubleshooting |
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Table of Contents |
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Page No |
RF Description and Troubleshooting ................................................................................................... |
5 |
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Introduction ........................................................................................................................................... |
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5 |
RF key component placement |
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7 |
RF test points ......................................................................................................................................... |
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8 |
Receiver ................................................................................................................................................. |
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8 |
Transmitter ........................................................................................................................................... |
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9 |
Synthesizer ........................................................................................................................................... |
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9 |
RF in General............................................................................................................................................ |
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10 |
RF power supply configuration ....................................................................................................... |
12 |
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General specifications of transceiver RH-19/RH-50 ................................................................ |
13 |
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Receiver Description and Troubleshooting...................................................................................... |
14 |
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General instructions for RX troubleshooting .............................................................................. |
14 |
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Measuring RX I/Q signals using RSSI reading .......................................................................... |
14 |
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Measuring RX performance using SNR measurement ........................................................... |
16 |
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Measuring front-end power levels using spectrum analyzer............................................... |
19 |
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Measuring analogue RX I/Q signals using oscilloscope......................................................... |
19 |
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Fault finding chart of the receiver ................................................................................................ |
21 |
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RX signal paths ................................................................................................................................... |
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23 |
Antenna switch (RX/TX switch) .................................................................................................... |
23 |
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RX front-end ...................................................................................................................................... |
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24 |
RX paths of Mjoelner RF ASIC....................................................................................................... |
24 |
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Transmitter Description and Troubleshooting ................................................................................ |
25 |
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General instructions for TX troubleshooting .............................................................................. |
25 |
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TX signal paths .................................................................................................................................... |
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25 |
Antenna switch (TX/RX switch) .................................................................................................... |
27 |
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GSM (GSM850/900) transmitter .................................................................................................... |
27 |
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General instructions for GSM850/GSM900 TX troubleshooting......................................... |
27 |
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GSM1800 (DCS/PCN) transmitter .................................................................................................. |
31 |
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General instructions for GSM1800 TX troubleshooting ........................................................ |
31 |
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Fault finding chart for GSM1800 transmitter.......................................................................... |
33 |
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GSM1900 (PCS) transmitter ............................................................................................................ |
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34 |
General instructions for GSM1900 TX troubleshooting ........................................................ |
34 |
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Fault finding chart for GSM1900 transmitter.......................................................................... |
36 |
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Synthesizer Description and Troubleshooting ................................................................................ |
37 |
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General instructions for synthesizer troubleshooting .............................................................. |
37 |
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Check synthesizer operation ........................................................................................................... |
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37 |
26 MHz reference oscillator (VCXO) ............................................................................................. |
38 |
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VCO ......................................................................................................................................................... |
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38 |
Fault finding chart for PLL synthesizer ........................................................................................ |
39 |
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Frequency lists ..................................................................................................................................... |
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41 |
GSM850 (RH-50) .............................................................................................................................. |
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41 |
GSM900 (RH-19) .............................................................................................................................. |
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42 |
GSM1800 (RH-19/RH-50).............................................................................................................. |
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43 |
GSM1900 (RH-19/RH-50).............................................................................................................. |
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44 |
DC supply current check ................................................................................................................... |
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45 |
RF Tuning Instructions .......................................................................................................................... |
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46 |
General instructions for RF tuning ................................................................................................ |
46 |
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Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 3 |
RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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RF tuning after repairs ...................................................................................................................... |
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46 |
RX calibration ...................................................................................................................................... |
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46 |
RX calibration GSM850/900.......................................................................................................... |
47 |
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RX calibration GSM1800 (DCS/PCN)........................................................................................... |
51 |
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RX calibration GSM1900 (PCS)..................................................................................................... |
53 |
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RX band filter response compensation ......................................................................................... |
56 |
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RX band filter response GSM850/GSM900 ............................................................................... |
56 |
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RX band filter response GSM1800 (DCS/PCN) ......................................................................... |
58 |
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RX band filter response GSM1900 (PCS) ................................................................................... |
61 |
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RX channel select filter calibration ............................................................................................... |
65 |
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RX AM suppression ............................................................................................................................ |
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65 |
TX power level tuning ........................................................................................................................ |
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66 |
TX power level tuning GSM850/GSM900 .................................................................................. |
66 |
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TX power level tuning GSM1800 (DCS/PCN) ............................................................................ |
68 |
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TX power level tuning GSM1900 (PCS) ...................................................................................... |
69 |
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TX I/Q tuning ........................................................................................................................................ |
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71 |
TX I/Q tuning GSM850/GSM900 .................................................................................................. |
71 |
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TX I/Q tuning GSM1800.................................................................................................................. |
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77 |
TX I/Q tuning GSM1900.................................................................................................................. |
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81 |
Appendices
Appendix A: FLALI Test Cases with Hints for Repair Appendix B: FinUI Test Cases with Hints for Repair
Appendix C: Component Placement with Test Points and Detailed Description
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Issue 3 05/2004 |
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Company Confidential |
RH-19/RH-50 |
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Nokia Customer Care |
7 - RF Description and Troubleshooting |
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RF Description and Troubleshooting
Introduction
The sections below provide instructions how to check, repair and calibrate the RF section of RH-19/RH-50 phones.
It is assumed that for tuning and repair the phones are disassembled and tested within a repair jig MJS-52.
The following types of measurements can be done for diagnosis and repair of RH-19/RH- 50 phone modules:
•RF measurements shall be done using a Spectrum Analyzer together with a high-fre- quency probe. (Note, that signal will be significantly attenuated). Correct attenuation can be checked using a “good” phone board for example.
•LF (Low frequency) and DC measurements shall be done with a 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 CMU200 can be used as signal generator. The signal generator is connected to the antenna port using the repair jig MJS-52.
•Output level measurements of the transmitter shall be done with a power meter, which is connected to the antenna port using the repair jig MJS-52.
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 (as stated on MJS-52) and the connecting cable when realigning the phone.
Most RF semiconductors are static discharge sensitive. ESD protection must be used during repair (wrist straps and ESD proof soldering irons).
Mjoelner RF ASIC is moisture sensitive. Therefore, Mjoelner RF ASIC must be in appropriate condition or 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 the following sections there are a lot of discrete components (resistors, inductors and capacitors) for which troubleshooting is done by checking its proper soldering and complete assembly on the PWB. Capacitors and resistors can be checked by means of an ohm-meter, but be aware: in-circuit measurement results have to be evaluated carefully.
Note: In this document there are example measurements being depicted with Phoenix pictures. This version of Phoenix however, is not the latest version.
Note: There are two different kinds of VCOs applicable (FDK and Matsushita).
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2004 Nokia Corporation. |
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RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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Note: There are different kinds of PAs applicable (Agilent and Renesas (RH-19) and Renesas (RH-50)).
Below the following abbreviations can be used interchangeably:
GSM850 and (E)GSM900 to refer to GSM low band.
DCS or PCN or GSM1800 GSM medium band.
PCS and GSM1900 GSM high band.
Page 6 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
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Company Confidential |
RH-19/RH-50 |
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Nokia Customer Care |
7 - RF Description and Troubleshooting |
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RF key component placement
Figure 1: RF key component placement
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Position |
Component Name |
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Supplier and Description |
Code |
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N801 |
TX-PA |
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Agilent, QCPM8893 (RH-19) |
4350369 |
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Renesas, PF08125B-03 (RH-19) |
4350409 |
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Renesas, PF08132B7 (RH-50) |
4359007 |
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L801 |
Directional Coupler |
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Murata, LDC15D190A0010A (RH-19) |
4551015 |
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Murata, LDC21836M19D-185 (RH-50) |
4550197 |
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Z601 |
Antenna Switch Module |
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Hitachi Metals, SHS-L090 (RH-19) |
4510385 |
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SHS-L080NT (RH-50) |
4550281 |
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Z602 |
SAW1800 RX |
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Epcos, B7714 |
4511313 |
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Z603 |
SAW1900 RX |
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Epcos, B7720 |
4511367 |
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Z604 |
SAW900 RX (RH-19) |
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Epcos, B7710 (RH-19) |
4511279 |
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SAW850 RX (RH-50) |
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Murata, SAFSD881MCLOTO4R13 (RH-50) |
4511323 |
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Z701 |
SAW900 TX (RH-19) |
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Epcos, B7715 (RH-19) |
4511311 |
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SAW850 TX (RH-50) |
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Murata, SAFSD836MFLOTO4R13 (RH-50) |
4511317 |
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N601 |
Mjoelner |
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Infineon, F3a |
4370867 |
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B601 |
XTAL |
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NDK |
4510337 |
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G701 |
VCO |
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FDK, IT016 (RH-19) |
4350315 |
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Matsushita, ENFVJW2S05 (RH-19) |
435B036 |
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Matsushita EVFVZ6P28 (RH-50) |
4350391 |
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Issue 3 05/2004 2004 Nokia Corporation. Page 7
RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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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 following illustration small circles show the locations of the test points.
Receiver
Figure 2: Test points of the receiver
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RXX PCSGSM |
RXQINN |
Antenna Feed |
RX DCS |
RX GSM |
(J614) |
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RX PCS |
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RXQINP |
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(J613) |
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RXIINN |
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(J612) |
CONT2
(VANTH) RXIINP
(J611)
CONT3
(VANTL)
CONT1
(VANTM) INPL / INML
INPH /
INMH
INPM /
INMM
Page 8 |
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Company Confidential |
RH-19/RH-50 |
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Nokia Customer Care |
7 - RF Description and Troubleshooting |
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Transmitter
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Figure 3: Test points of the transmitter |
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CONT1 |
Antenna Feed |
(VANTM) |
CONT2 |
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TXIOUTP |
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(VANTH) |
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TXIOUTN |
CONT3 |
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TXQOUTP |
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(VANTL) |
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TXQOUTN |
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DET |
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Pout |
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TXP |
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EGSM |
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(J701) |
Pout |
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TXC |
DCS / PCS |
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(J702) |
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TX_850 (RH-50) |
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TX_900 (RH-19) |
TX_1800 |
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Synthesizer
Figure 4: Test points of the synthesizer
VR3 |
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VREF1 |
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VIO |
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Utune
VCOout
VR7
RFCLK_I
VR5
VR1A
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RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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RF in General
The RH-19/RH-50 RF front-end is a triple-band direct conversion transceiver. Using direct conversion, no intermediate frequencies are used for upor down-conversion.
The VCO oscillates on the double respectively quadruplicate 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). Upor downconversion is done in one step, directly between RF frequency and base band. All upand down-conversion takes place in the RF ASIC named Mjoelner (N601).
Mjoelner RF ASIC also contains PLL and LNAs for all used bands. A DC control section is included to power and/or control (E)GSM 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 HSCSD (High Speed Circuit Switched Data) and GPRS (General Packed Radio Service), meaning multi-slot operation. (This does not require special equipment or procedures in repair situations.)
The following diagrams show the RF frequency scheme and the RF block diagram.
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Figure 5: RF frequency plan |
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Mjoelner |
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EGSM: 925-960 MHz (RH-19) |
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I-signal |
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RX |
GSM: 869-894 MHz (RH-50) |
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Q-signal |
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DCS: 1805-1880 MHz |
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PCS: 1930-1990 MHz |
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f/4 |
f/2 |
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f |
f |
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3420-3980 MHz (RH-19) |
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39802 6-3980 MHz (RH-50) |
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MHz |
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f |
f |
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f/4 |
f/2 |
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PLL |
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26 MHz |
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DCS: 1710-1785 MHz |
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XTal |
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LPRFCLK |
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PCS: 1850-1910 MHz |
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1/1 |
RFCLK |
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1/2 |
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EGSM: 880-915 MHz |
(RH-19) |
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I-signal |
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TX |
GSM: 824-849 MHz (RH-50) |
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Q-signal |
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Page 10 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
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Company Confidential |
RH-19/RH-50 |
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Nokia Customer Care |
7 - RF Description and Troubleshooting |
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Figure 6: RF block diagram
RX850/RX900
Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 11 |
RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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RF power supply configuration
All power supplies for the RH-19/RH-50 RF Unit are generated in the UEM IC (D200). 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.
Figure 7: RF power distribution diagram
VR1A
VR2
VR3
UEM
VR4
VR5
VR6
VR7
VIO
VREF01
VBAT
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4.75 V |
3.2 % |
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charge pump (VDDCP) |
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0.45 mA |
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2.78 V |
3 % |
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Tx modulator (VDDTX) |
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85 mA |
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Dig. control (VDDDIG)
Ant. switch control lines (through Mjoelner)
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2.78 V |
3 % |
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VCXO (VDDXO) |
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3.5 mA |
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2.78 V |
3 % |
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BB buffer (VDDBBB) |
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Rx BB section (VDDRXBB) |
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1414mAmA(Tx850/Tx900),(Tx900), 28 (Rx)28 (Rx) |
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2.78 V |
3 % |
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Tx buffer (through Mjoelner) |
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PLL prescaler (VDDPRE) |
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41 mA |
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dividers, LO buffers (VDDLO) |
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2.78 V |
3 % |
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PLL counters (VDDPLL) |
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Rx front end (VDDRXF) |
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11 mA |
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2.78 V |
3 % |
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VCO |
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14 mA |
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1.8 V |
4.5 % |
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13/26 MHz (SELADDR) |
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0.02 mA |
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1.35 V |
2 % |
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dig. interface (VDDDL) |
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bias reference (VBEXT) |
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100 uA |
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3.6 V |
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Triple band PA |
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Page 12 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
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Company Confidential |
RH-19/RH-50 |
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Nokia Customer Care |
7 - RF Description and Troubleshooting |
|||||
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General specifications of transceiver RH-19/RH-50
Parameter |
Unit |
|
|
Cellular System |
GSM850, (E)GSM900, GSM1800, GSM1900 |
|
|
RX Frequency Band |
GSM850: 869 ... 894 MHz (RH-50) |
|
EGSM: 925 … 935 MHz (RH-19) |
|
GSM900: 935 … 960 MHz (RH-19) |
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GSM1800: 1805 ... 1880 MHz (RH-19/RH-50) |
|
GSM1900: 1930 … 1990 MHz (RH-19/RH-50) |
|
|
TX Frequency Band |
GSM850: 824 ... 849 MHz (RH-50) |
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EGSM: 880 … 890 MHz (RH-19) |
|
GSM900: 890 … 915 MHz (RH-19) |
|
GSM1800: 1710 ... 1785 MHz (RH-19/RH-50) |
|
GSM1900: 1850 … 1910 MHz (RH-19/RH-50) |
|
|
Output Power |
GSM850: +5... +33 dBm (3.2 mW ... 2 W) (RH-50) |
|
EGSM: +5 … +33 dBm (3.2 mW … 2 W) (RH-19) |
|
GSM900: +5 … +33 dBm (3.2 mW … 2 W) (RH-19) |
|
GSM1800: +0 … +30 dBm (1.0 mW … 1 W) (RH-19/RH-50) |
|
GSM1900: +0 … +30 dBm (1.0 mW … 1 W) (RH-19/RH-50) |
|
|
Duplex Spacing |
GSM850: 45 MHz (RH-50) |
|
EGSM: 45 MHz (RH-19) |
|
GSM900: 45 MHz (RH-19) |
|
GSM1800: 95 MHz (RH-19/RH-50) |
|
GSM1900: 80 MHz (RH-19/RH-50) |
|
|
Number of RF Channels |
GSM850: 124 |
|
EGSM: 50 + 124 = 174 |
|
GSM900: 124 |
|
GSM1800: 374 |
|
GSM1900: 299 |
|
|
Channel Spacing |
200 kHz (each band) |
|
|
Number of TX Power Levels |
GSM850: 15 (RH-50) |
|
EGSM: 15 (RH-19) |
|
GSM900: 15 (RH-19) |
|
GSM1800: 16 (RH-19/RH-50) |
|
GSM1900: 16 (RH-19/RH-50) |
|
|
Sensitivity, static channel |
GSM850: -102 dBm (RH-50) |
|
EGSM: -102 dBm (RH-19) |
|
GSM900: -102 dBm (RH-19) |
|
GSM1800: -102 dBm (+25°C) (RH-19/RH-50) |
|
GSM1900: -102 dBm (RH-19/RH-50) |
|
|
Frequency Error, static channel |
< 0.1 ppm |
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RMS Phase Error |
< 5.0 ° |
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Peak Phase Error |
< 20.0 ° |
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Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 13 |
RH-19/RH-50 |
Company Confidential |
|
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|
||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
|||||
|
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|
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Receiver Description and Troubleshooting
General instructions for RX troubleshooting
Connect the phone to a PC with dongle and DAU-9T cable (RS232) (or DKU-5 cable (USB)). Follow the instructions below.
Connect the phone to a power supply (DC voltage of 3.6V) and a RF signal generator.
Measuring RX I/Q signals using RSSI reading
Start Phoenix Service Software and open FBUS connection. |
|
|
Select |
Scan Product |
Ctrl-R |
Wait until phone information is shown in the lower right corner of the screen. Set operating mode to local mode
Select |
Maintenance |
|
Alt-M |
|
Testing |
|
T |
|
RF Controls |
F |
|
Wait until the RF Controls window has popped up |
|
||
Select |
Band |
GSM850, GSM 900, GSM1800 |
|
|
|
or GSM1900 |
|
|
Active unit |
RX |
|
|
Operation mode |
Burst |
|
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RX/TX Channel |
190 (GSM850) or 37 (GSM900) or |
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700 (GSM1800) or 661 (GSM1900) |
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Select |
Maintenance |
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Alt-M |
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Testing |
|
T |
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RSSI reading |
R |
|
Page 14 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
|
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|
Company Confidential |
RH-19/RH-50 |
|
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|
||
Nokia Customer Care |
7 - RF Description and Troubleshooting |
|||||
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The setup should now look like this:
Note: This is an example for GSM850 (RH-50), other tunings will show a different figure.
Make the following settings on your signal generator:
1.Frequencies:
• |
GSM850: |
881.66771 MHz (channel 190 +67710 kHz offset) |
|
• |
GSM900: |
942.46771 MHz (channel 37 + 67.710 kHz offset) |
|
• |
GSM1800: |
1842.86771 MHz |
(channel 700 + 67.710 kHz offset) |
• |
GSM1900: |
1960.06771 MHz |
(channel 661 + 67.710 kHz offset) |
2.RF power level:
•– 80dBm at the antenna connector of the phone/test jig (remembering to compensate for the cable and jig attenuation).
In RSSI reading click on Read now.
The resulting RSSI level should be – 80dBm ± 0.5dB in each band.
Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 15 |
RH-19/RH-50 |
Company Confidential |
|
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|
|||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
||||||
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Measuring RX performance using SNR measurement |
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Start Phoenix Service Software and open FBUS connection. |
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||
Select |
Scan Product |
Ctrl-R |
|
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|
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Wait until phone information is shown in the lower right corner of the screen. |
|||||||
Set operating mode to local mode. |
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|
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Select |
Maintenance |
Alt-M |
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Testing |
T |
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RF Controls F |
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Wait until the RF Controls window has popped up. |
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|
||
Select |
Band |
GSM850 (RH-50), GSM 900 (RH-19) |
|||||
|
|
or GSM1800 or GSM1900 |
|||||
|
Active unit |
RX |
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Operation mode |
Burst |
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RX/TX Channel |
190 (GSM850) or 37 (GSM900) or |
|||||
|
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700 (GSM1800) or 661 (GSM1900) |
|||||
Select |
Maintenance |
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Alt-M |
||||
|
Testing |
|
T |
||||
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SNR Measurement |
M |
|||||
Select |
Fast SNR (Radio Button) |
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Page 16 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
|
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Company Confidential |
RH-19/RH-50 |
|
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|
|
|
||
Nokia Customer Care |
7 - RF Description and Troubleshooting |
|||||
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|
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The setup should now look like this in case of e.g. RH-50 (GSM850):
Choose respective band (GSM850 (RH-50), GSM900 (RH-19), GSM1800, GSM1900). Press SNR measurements. Start button window pops up, e.g. for GSM850 band:
Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 17 |
RH-19/RH-50 |
Company Confidential |
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||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
|||||
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|
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Set the signal generator as shown in the above window, remembering to compensate for the cable and test jig attenuation losses.
Press OK and the window closes.
Read the SNR result. The values should be:
• |
RH-50: GSM850 ---- |
> 20dB |
|
• |
RH-19: GSM900 ---- |
> 20dB |
|
• |
RH-19/RH-50: GSM1800 --- |
> 18dB |
|
• |
RH-19/RH-50: GSM1900 --- |
> 18dB |
|
Page 18 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
|
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Company Confidential |
RH-19/RH-50 |
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|
||
Nokia Customer Care |
7 - RF Description and Troubleshooting |
|||||
|
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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 a resistive probe (50Ohm semi-rigid cable).
Start Phoenix Service Software and open FBUS connection.
Select |
Scan Product |
Ctrl-R |
Wait until phone information is showing in the lower right corner of the screen.
Set operating mode to local mode.
Select |
Maintenance |
Alt-M |
|
Testing |
T |
|
RF Controls F |
|
Wait until the RF Controls window pops up |
||
Select |
Band |
GSM 850 (RH-50) or GSM900 (RH-19), |
|
|
GSM1800 or GSM1900 |
|
Active unit |
RX |
|
Operation mode |
Continuous |
|
RX/TX Channel |
190 (GSM850) or 37 (GSM900) or |
|
|
700 (GSM1800) or 661 (GSM1900) |
Please refer to the fault finding chart 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 exist dedicated test points for RX I and Q signals. Input level = -80dBm.
Start Phoenix Service Software and open FBUS connection.
Select |
Scan Product |
Ctrl-R |
Wait until phone information is showing in the lower right corner of the screen.
Set operating mode to local mode.
Select |
Maintenance |
Alt-M |
|
Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 19 |
|
RH-19/RH-50 |
Company Confidential |
|
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|||||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
|||||
|
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Testing |
T |
||||
|
RF Controls F |
|||||
Wait until the RF Controls window has popped up. |
||||||
Select |
Band |
GSM850, GSM 900, GSM1800 or |
||||
|
|
GSM1900 |
||||
|
Active unit |
RX |
||||
|
Operation mode |
continuous |
||||
|
RX/TX Channel |
190 (GSM850) or 37 (GSM900) or |
||||
|
|
700 (GSM1800) or 661 (GSM1900) |
||||
|
AGC |
14 |
|
|
|
|
Following picture should be displayed on an oscilloscope’s screen if the GSM receiver is working properly:
Signal amplitude |
1.25V |
DC offset |
1.35V |
Frequency |
67kHz |
Page 20 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
RH-19/RH-50 |
Company Confidential |
|
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|
||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
|||||
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Fault finding chart of the receiver
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(UBB) + AGCcalibrated
Therefore, don’t 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 it is not sure that incorrect re-calibration has been made, the following steps shall be done:
•Check if AGC calibration is within limits
•Check if SNR reading is o.k.
Use an oscilloscope to check levels of “RXIINN” and “RXQINN”.
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 pad J615 to the antenna switch Z601 (see RX fault finding "Check RXTX switch").
Page 21 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
05/2004 3 Issue
.Corporation Nokia 2004
22 Page
Make sure that |
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Synthesiser |
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RX Fault finding |
||
is working |
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Note: RF levels given in that chart are dependent on RF probe and must be validated with a known good sample |
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Apply -80dBm signal |
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from Generator |
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to Antenna Connector |
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phone: local, burst mode |
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EGSM, |
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EGSM, |
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RSSI |
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Osci: |
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Osci: |
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PCS, PCN |
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No |
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Apply -92dBm signal |
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PCS, PCN |
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No |
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and SNR |
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Yes |
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SA |
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Yes |
SA |
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RF-BB |
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RX I/Q |
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Yes |
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RSSI reading |
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from Generator |
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SNR measurement |
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wrong in all 3 |
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Z601 |
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Z601 |
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BB Error |
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serial |
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level |
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-80dBm |
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to Antenna Connector |
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EGSMout |
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EGSMout |
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Check UEM |
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all bands |
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bands |
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Interface |
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o.k. |
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all bands |
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phone: local, burst mode |
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? |
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-76dBm |
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-76dBm |
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o.k. |
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o.k. |
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RX calibration |
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Change generator level |
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BB Error |
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Change |
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to -55dBm |
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Check UPP |
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Mjolner |
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phone: local, |
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continous mode |
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Check |
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Check |
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Check |
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Check |
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Check |
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Bias |
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Bias |
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RxTx Switch |
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SAW |
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LNA |
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Calibrtion. |
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No |
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SA |
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SA |
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Osci: |
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Osci: |
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Osci: |
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SA |
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SA |
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SA |
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witin |
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Z601 |
Yes |
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Z604,Z602,Z603 |
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Yes |
LNA bias |
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Yes |
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RX -BB bias |
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LNAZ601 |
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Z601 |
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Z601 |
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Z601 |
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Z601 |
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Yes |
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limits |
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Rx output |
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SAWout |
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(VR6) |
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(VR4) |
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base voltage |
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EGSMout |
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EGSMout |
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EGSMout |
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EGSMout |
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EGSMout |
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? |
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(900,1800,1900) |
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both lines |
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=2.8V |
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=2.8V |
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=-76dBm0.8V |
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-76dBm |
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-76dBm |
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-76dBm |
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-76dBm |
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> -75dBm |
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>-78dBm |
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? |
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? |
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? |
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? |
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? |
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Yes
Rx chain functional
= to be done in all 3 bands 
=to be done in defective band only
No |
No |
No |
No |
No |
|
Change |
Change |
Check |
Check |
Change |
|
Z601 |
Z604,Z602,Z603 |
Mjolner |
|||
C620, C632 |
C871 |
||||
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and |
and |
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BB (UEM) |
BB (UEM) |
|
=to be done only once (common for all bands)
Care Customer Nokia
RX 8: Figure |
|
Company |
finding fault |
Description RF - 7 |
Confidential |
|
Troubleshooting and |
50-19/RH-RH |
RH-19/RH-50 |
Company Confidential |
|
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|
||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
|||||
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|
RX signal paths
The signal paths of the receiver are shown in following block diagram. Note that the diagram shows GSM900 (or GSM850) receiver (above), GSM1900 receiver (middle) and GSM1800 receiver (below).
Figure 9: RX signal paths
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VR6 |
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Rx |
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VRX |
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supply |
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VR4 |
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filter |
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FXR DDV |
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BBXR DDV |
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LNA |
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Bias |
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SAW |
INPL |
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BIQUA |
RXIP |
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RX |
RX850/RX900 |
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LNA |
Pre- |
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D |
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RX900 |
INML |
gain |
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RXIM |
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GSM |
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BBAMP |
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DCN1 |
AGC |
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LPF1 |
DCN2 |
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TX |
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LPF2 |
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Switch |
RX |
SAW |
INPH |
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BIQUA |
RXQP |
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Pre- |
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D |
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PCS |
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LNA |
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Ant |
RX1900 |
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TX |
INMH |
gain |
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BBAMP |
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DCN1 |
AGC |
RXQM |
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LPF1 |
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2 |
2 |
DCN2 |
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PCN |
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2 |
2 |
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LPF2 |
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SAW |
INPM |
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RX |
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RX1800 |
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LNA |
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INMM |
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VDDLO |
||
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VANTL / VANTM / VANTH |
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VDDDIG |
1/2 |
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1/4 |
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3 |
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RF |
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Controls |
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VDDRXBB |
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RF |
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Controls |
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Mjølner |
|
Antenna switch (RX/TX switch)
Signal path of RF: From the antenna-pad (J615) the RF signal is fed through the antenna low pass filter (C601, L608, C602) to the antenna switch (Z601).
The antenna switch has the function of a diplexer which consists of two paths, a GSM850/GSM900 and a combined GSM1800/GSM1900. The GSM850/GSM900 input signals pass the switch to the GSM_RX output. GSM1800/GSM1900 input signals pass to PCN_RX output or respectively to PCS_RX output, depending on the control signal VANTH (Cont2).
Signal paths:
• |
GSM850/GSM900: RX1-GSM output of the antenna switch → GSM850/GSM900 |
|
|
SAW filter (Z604). |
|
• |
GSM1800: RX2-DCS output of the antenna switch → |
GSM1800 SAW filter (Z602). |
• |
GSM1900: RX3-PCS output of the antenna switch → |
RX GSM1900 SAW filter |
|
(Z603). |
|
The antenna switch including routed lines has following typical insertion losses:
•GSM850 (RH-50): 1.3dB
•GSM900 (RH-19): 1.3dB
•GSM1800 (RH-19/RH-50): 1.6dB
•GSM1900 (RH-19/RH-50): 1.6dB
Page 23 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
|
|
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|
Company Confidential |
RH-19/RH-50 |
|
|
|
|
|
||
Nokia Customer Care |
7 - RF Description and Troubleshooting |
|||||
|
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|
RX front-end
The RX front-end includes three SAW filters for GSM850/GSM900 (Z604), GSM1800 (Z602) 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.
The SAW filters have maximum insertion losses of
•GSM850 (RH-50): 3.5dB
•GSM900 (RH-19): 3.5dB
•GSM1800 (RH-19/RH-50): 4.0dB
•GSM1900 (RH-19/RH-50): 4.0dB
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 three bands: GSM850/GSM900, GSM1800 and GSM1900.
•Two PRE-GAIN amplifiers, one for GSM850/GSM900 and one common for GSM1800 and GSM1900.
•Two passive I/Q mixers (MIX), one for GSM850/GSM900 and one common for GSM1800 and GSM1900.
The BB signal paths consist of:
•Base band 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). These 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.
Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 24 |
RH-19/RH-50 |
Company Confidential |
|
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|
||
7 - RF Description and Troubleshooting |
Nokia Customer Care |
|||||
|
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|
Transmitter Description and Troubleshooting
General instructions for TX troubleshooting
Connect a 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 the measurement equipment (10dB to 20dB are recommended for a spectrum analyzer or a power meter). Assure not to overload or damage the equipment.
1Connect the phone to a PC with DAU-9T cable (RS232) (or DKU-5 cable (USB)) and dongle.
2Provide the phone with power supply (3.6V).
3Start Phoenix Service Software and open FBUS connection.
4 Select Scan Product Ctrl-R
and wait until phone information is shown in the lower right corner of the screen.
Follow the instructions as given 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 on the diagram below.
Note: The diagram shows both GSM850/GSM900 transmitter (below) and GSM1800/GSM1900 transmitter (above).
Page 25 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
|
|
|
|
|
Company Confidential |
RH-19/RH-50 |
|
|
|
|
|
||
Nokia Customer Care |
7 - RF Description and Troubleshooting |
|||||
|
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|
|
Figure 10: Transmitter signal paths
VANTL / VANTM / |
VDDDIG |
3
RF
Controls
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VB_DET |
VDDRXBB |
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1/2 |
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1/4 |
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VTXLOL |
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VTXLOH |
RF |
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VTXBH |
Controls |
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VTXBL |
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PCN/PCS |
OUTHP |
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2 |
2 |
2 |
2 |
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TX |
Balun |
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||||
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OUTHM |
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Dir. Coupler PA |
Open |
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PCN |
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collector |
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Ant |
PCS |
VTX |
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Switch |
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SAW |
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TX |
Buffer |
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Open |
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OUTLP |
collector |
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GSM |
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EGSM |
OUTLM |
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PW- |
DET |
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DET |
loop |
PLFB1 |
PWC |
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filter |
PLFB2 |
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Mjølner |
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VPCH/VPCL |
TX |
TX |
V |
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P |
C |
D |
2 |
2 |
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2 |
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D |
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Supply |
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filter |
TX |
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TX |
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PA_IDENT |
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VT |
Q |
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P/ |
IP/ |
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X |
TX |
TX |
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Q |
IM |
VBATTRF |
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TXP TXC |
VR2 |
M |
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The balanced TX IQ baseband signals (TXIOUTP, TXIOUTN, TXQOUTP, TXQOUTN) are provided by the base band 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 base band signals, one for GSM850/GSM900 and one common for GSM1800/GSM1900. The base band signal is up-converted with the LO signal corresponding to the wanted TX channel. Both RF-TX outputs (850/900MHz and 1800/1900MHz) of the Mjoelner RF ASIC are delivering balanced signals.
The GSM850/GSM900 output signal of the Mjoelner RF ASIC is fed through the GSM TX SAW filter (balanced to single ended), a 3dB pad, and the 850/900MHz buffer to the GSM input of the power amplifier (PA).
The GSM1800/1900 output signal of the Mjoelner RF ASIC is fed through the TX balun (T701) (balanced to single ended), and a 3dB pad to the GSM1800/1900 input of the power amplifier (PA).
The Triband PA has a maximum output power of approx. 35dBm at 850/900MHz and 33dBm at 1800/1900MHz. DC-power supply is delivered directly from the battery connectors.
The RF output power is controlled by the power control loop. From the output of the PA
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2004 Nokia Corporation. |
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RH-19/RH-50 |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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both signal are going through the dual directional coupler (one of the power control loop components) to the antenna switch.
Note: There are two different kinds of PAs applicable (from Renesas (RH-50) or Agilent and Renesas (RH19)).
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 CONT1, CONT2 and CONT3.
The following table shows the possible different states.
CONT1 |
CONT2 |
CONT3 |
GSM RX |
DCS RX |
PCS RX |
GSM TX |
DCS/PCS |
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[Volt] |
[Volt] |
[Volt] |
TX |
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0 |
0 |
0 |
X |
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0 |
0 |
0 |
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X |
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0 |
0 |
2.7 |
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X |
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0 |
2.7 |
0 |
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X |
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X |
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2.7 |
2.7 |
0 |
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X |
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To switch the TX-DCS/PCS path both signals cont1 and cont2 are activated. This increases the isolation from the TX-DCS/PCS path to the RX-DCS path and reduces the RF-power that is fed back to Mjoelner.
GSM (GSM850/900) transmitter
General instructions for GSM850/GSM900 TX troubleshooting
Start the preparations as described in section “General Instructions for TX Troubleshooting”.
Set operating mode to local mode.
Select |
Maintenance Testing |
RF Controls |
Wait until the RF Controls window has popped up |
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Select |
Band |
GSM850 or GSM 900 |
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Active unit |
TX |
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Operation mode |
Burst |
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RX/TX Channel |
190 (GSM850) or |
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37 (GSM900) |
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2004 Nokia Corporation. |
Issue 3 05/2004 |
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Company Confidential |
RH-19/RH-50 |
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Nokia Customer Care |
7 - RF Description and Troubleshooting |
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TX PA Mode |
Free |
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TX Power Level |
10 |
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TX Data Type |
Random |
The setup should now look like this in case of e.g. GSM850 (RH-50):
Now the measurement equipment should detect the following output signal of the phone:
Pout = +23dBm @ 897.4MHz or +23dB @ 836.6 MHz
If this is not the case, then go to the following fault finding chart.
Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 28 |
RH-19/RH-50 |
Company Confidential |
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7 - RF Description and Troubleshooting |
Nokia Customer Care |
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Fault finding chart for GSM850 or GSM900 transmitter
In the following, the TXP signal is used as a trigger-signal. For this purpose a TXP test point is provided on the PWP, refer to figure 3 “Test points of the transmitter”.
Use Phoenix to select
TX_Data Type: "1" or "0"
TX Power Level: 10
Yes
Oscilloscope |
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R612 |
VREF01 |
Vdc = |
1.35 Volt |
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C627 |
VR2 |
Vdc = |
2.78 Volt |
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C717 |
TXP |
V = |
1.8 Volt |
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C623 |
VR5 |
Vdc = |
2.78 Volt |
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C605 |
VR3 |
Vdc = |
2.78 Volt |
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Yes |
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Oscilloscope |
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C715 |
TXIOUTP |
67kHz |
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Vac = 0.4Vpp, Vdc = 1.1V |
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C715 |
TXIOUTN |
67kHz |
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Vac = 0.4Vpp, Vdc= 1.1V |
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C716 |
TXQOUTP |
67kHz |
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Vac = 0.4 Vpp, Vdc = 1.1V |
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C716 |
TXQOUTN |
67kHz |
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Vac = 0.4Vpp, Vdc = 1.1V |
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Yes |
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Oscilloscope |
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R823 |
VTXB_850/900 |
Vdc = 2.78 Volt |
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C702 |
CONT1 |
Vdc = 0 Volt |
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C701 |
CONT2 |
Vdc = 0 Volt |
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C703 |
CONT3 |
Vdc = 2.78 Volt |
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C803 |
VBD |
Vdc - 2.78 Vol |
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Yes |
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Spectrum analyzer |
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Z701 out, R729 in |
TX_850/900 |
P>= -3 dBm, |
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836,6 MHz (RH-50), |
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897,4 MHz (RH-19) |
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Compare with good |
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sample |
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Yes |
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Use Phoenix to select |
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TX_Data Type: Random |
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TX Power Level: 10 |
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Yes |
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Spectrum analyzer |
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Check PA N801 |
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L801 B1_in |
No |
Check Power Loop |
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(PA N801 Pout_GSM) |
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L801,V801 |
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Power = +25dBm, 897,4/ |
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Check TXC |
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836,6 MHz |
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Yes |
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Spectrum analyzer |
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Check |
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RF-connector |
No |
Directional Coupler (L801) |
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Pout = +23dBm, 897,4/ |
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Antenna Switch (Z601) |
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836,6MHz |
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Yes |
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GSM TX |
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OK |
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No Check
Base Band
Check
No
Baseband
Check:
Mjoelner Serial
No Interface
Mjoelner
No |
Check |
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GSM TX SAW Filter |
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Mjoelner |
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Synthesizer |
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Page 29 |
2004 Nokia Corporation. |
Issue 3 05/2004 |
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|
Company Confidential |
RH-19/RH-50 |
|
|
|
|
|
||
Nokia Customer Care |
7 - RF Description and Troubleshooting |
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Issue 3 05/2004 |
2004 Nokia Corporation. |
Page 30 |
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