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PAMS Technical Documentation
Troubleshooting and Tuning Instructions
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Receiver troubleshooting diagram for GSM900
Receiver troubleshooting diagram for GSM900
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Apply –90dBm
942.46771MHz signal
from generator to anten-
na connector
Oscilloscope at RX_I
Signal 700mVpp
DC offset 1.35V Fre-
quency 67.7kHz
No
Change ge-
nerator level
to –50dBm
Spectrumanalyzer
900 LNA out
–61 dBm
Spectrumanalyzer
900 1st SAW out
–80 dBm
EGSM RX chain func-
tional
Spectrumanalyzer
900 bal out
–66 dBm
Oscilloscope
VR4 2.7V
Check Hagar serial
interface (burst mo-
de)
Check Z501, C505,
C506, L501
Check Baseband
Spectrumanalyzer
4G VCO out
3769.6MHz
∼
–30 dBm (*
Synthesizer troubles-
hooting
Check Hagar N600
Oscilloscope
LNA_G 2.7V
LNAB_G 2.7V
Spectrumanalyzer
V500, RFout –57
dBm
Check C502
Oscilloscope
V500, RFout 2.7V
V500, RFin 0.8 V
Check V500, C501,
L502, L503
Check V500,
L500, R502
Oscilloscope
VR4 2.7V
Check Hagar seri-
al interface Check
R501
Check Hagar
N600
Check Base-
band
Spectrumanalyzer
900_RX
–79 dBm
Check An-
tenna switch
Z500
Check dual RX SAW
Z520
* Spectrumanalyzer
reading with 1 kohm
passive probe (right val-
ue add +26 dB)
All spectrumanalyzer reading
values are measured with 1
kohm passive probe (use
tweezers to connect the
probe ground to the nearest
PWB ground). Reading value
is represented w26
dB compensation.