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Chapter 4, Troubleshooting
Questionable Measurement Results
Rho Measurements Sources of errors in rho measurement include the following:
Input signal is outside the measurement range of the PCS Interface
The specified range for rho measurements with the PCS Interface is
−13 to +30 dBm (50 µW to 1 W) when testing base station transmitters. Verify
that the signal applied to the RF IN/OUT port of the PCS Interface falls within
this range before continuing with your tests.
Channels other than the Pilot are on.
For modulation quality measurements on a CDMA signal, you must have only the
pilot channel active. If other channels (sync, paging, or traffic) are on, you will
get poor rho readings, if you get readings at all. Turn off any other code channels,
if they are on, before trying to re-measure rho.
Other sources of interference exist in the channel.
If other interference sources are present within the CDMA channel, you will see
degraded rho performance. The spectrum analyzer modes may be used to search
for other interference.
Code Domain
Measurements
Sources of errors in Code Domain measurements include the following:
Channels other than the Pilot are not turned up.
Unlike the rho measurements example, code domain measurements require other
code channels to be turned on. In most cases, in addition to the Pilot channel, you
will have a sync channel, a paging channel, and one or more traffic channels
enabled.
Receiver Tests Sources of errors in receiver tests include the following:
Cable loss values are incorrect
Since the Software will compensate for cable loss between the Test System and
your base station’s receiver test port, it is very important that you have the correct
values entered into the Configuration Information Menu.
You can view the loss values in the
Configuration Information Menu. If
they do not match your setup (do not forget to allow for losses through couplers,
attenuators, and so forth) go to RX Measurement Path Loss and enter the
correct value.