User Guide

PAMS Technical Documentation Service Software
NSB-5
Issue 1 03/01 Nokia Mobile Phones Ltd. Page 35
If everything went well, the reported values should approximately be the following:
Difference between the two neighbor AGC steps: 10 20
Troubleshooting
If the calibration is unsuccessful, the software normally reports ”Unable to read data
from phone” or ”Failed to set high reference” or ”Failed to set low reference”. In any case,
check first the basic functionality of the receiver chain: Verify that the RF generator fre-
quency and level are set as in the calibration (e.g., to the high reference value). Next, go
to the RSSI reading menu (under RF controls). If the reading is very low, there is some-
thing broken in the receiver and it must be found by measuring voltages and signal levels
at different points (information on these can be found elsewhere in this manual).
If the RSSI reading seems to be within 5 to 10 dB of the RF input level, check that the
VCTCXO (G701) frequency is close enough to the required frequency. The easiest way to
check this is by measuring the UHF VCO (G702) frequency, because the absolute value of
the deviation is largest there. At the GSM1900 mid-channel, the UHF VCO frequency
should be 1473.0 MHz. If the deviation is larger than about +/–20 kHz, it is probable that
the VCTCXO is not operating correctly.
If both of these (RSSI reading and the frequency) seem to be correct and calibration still
fails, the most probable reason is that there is a lack of gain somewhere or that the AGC
gain control slope in N600 is out of limits. This can be verified by varying (up and down)
the generator reference levels fromthose stated in the calibration procedure in 1-dB
steps. If the calibration only goes through some reference levels, the corrective action is
most probably changing N600 or N700.
Dialog mode: modal
RX Calibration dialog has the following items:
AFC information box:
Shows AGC,DAC voltage.
AGC List box (ALT+A):
AGC, DAC, Voltage and Difference. The difference column shows the difference between
tuned DAC values and mean straight line calculated from part slopes in dBs (see /1/).
This can be calculated when all measurement results have been received from phone.
Repeat button (ALT+R):
The measurement can be started again by pressing this button.
Parameter Low limit High limit
AFC init value
AFC slope
PSW slope
AGC 0 dB
AGC 57 dB
-80
135
250
175
440
80
230
350
325
740