Nokia RH-37 Series Rf Troubleshooting Instructions page 13

RH-37
Nokia Customer Care 6(b) - RF Troubleshooting Instructions
VrefRF02. The phone layout has dedicated test points for the analogue RX I and Q signals
(J512, J513).
The BB part is used to measure those signals by means of RSSI reading. This works only if
correct calibration has been carried out in production.
RSSIreading [dBm] = 20log(U /U ) - AGC
BB LSB calibrated
In order to check the levels and frequencies of RF signals, the following probe can be
used (note that only the core lead contacts the test point, the shielding of the coaxial
cable does not contact GND during the measurement):
Connect this probe via a coaxial cable and a DC block to a spectrum analyzer. The DC
block is important to protect the spectrum analyzer from DC levels, which superpose
the RF signal at several test points.
If both RX and TX path seem to be faulty, it has to be checked if the synthesizer is work-
ing.
Nokia Corporation
Issue 1 07/04 Page 13