User Guide

NPE-4
6 - Troubleshooting PAMS Technical Documentation
Page 6-32 ãNokia Corporation. Original
If no control voltage is present at VC1 or VC2 the RX/TX switch is open to the two RX
outlets GSM_Rx and DCS_Rx. The RX/TX switch will work as a diplexer and EGSM signals
pass to GSM_Rx and PCN signals to DCS_Rx.
From GSM_Rx the EGSM signal is feed to the Dual RX SAW filter (Z804) via C804.
Front-end
The EGSM front-end consists mainly of two SAW filters (Z804 and Z620) and one LNA
(V820) in-between. The SAW filters provides out-of-band blocking immunity, the LNA
provides front-end gain. The first SAW filter (Z804) is a DUAL package including SAW fil-
ter for both EGSM and PCN. The last SAW filter (Z620) is single ended input and bal-
anced output providing a balanced signal input for Hagar (N600).
The signal-path is through Z804 (In-band insertion-loss 3,5dB), through the matching
circuit (L821, L820 and C821) and to the EGSM LNA (V820, RFin).
From the LNA (V820, RF out) the signal is lead through C824, through the 2
nd
EGSM
SAW Z620 (In-band insertion-loss 3,5dB), through the balanced matching circuit (C626,
C627, L626) to Hagar (N600).
Hagar
The balanced RX signal is mixed with a signal from the local oscillator at the same fre-
quency as the wanted RX signal. After mixing the signal is converted to a single ended
signal in the DtoS (Differential to Single ended) amplifier. The signal is now filtered in a
BIQUAD filter to provide channel separation, amplified in the BB_Gain amplifier and DC
compensated in DCN2.
PCN Receiver
General instructions for PCN RX troubleshooting
Connect the the phone to a PC with DAU-9P cable and dongle and follow the following
instructions:
Start Phoenix Service Software
Select File Alt-F
Scan Product Ctrl-R
Wait until phone information shows in the lower right corner of the screen.
Set operating mode to local mode
Select Maintenance Alt-M
Tuning T
RF Controls F