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

Sources of errors in Code Domain measurements include the following:

Measurements

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 co rrect

 

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.

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