User`s guide

2-11
GPIB Tutorial and Examples
Example D - Adding Robustness
Example D - Adding Robustness
There are several additions which can be made to your program to increase its robustness:
❒ Check input power falls within +/-3dB specified analyser range
❒ Check DSP measurement status
❒ Check for Agilent 8922M/S error logs
❒ Provide a time-out for any measurements which do not complete
These checks add little value to a program designed to test phones which are known to
meet specification. In many cases the mobile being tested will be out of specification, the
phone may fail to produce a burst at the correct power and frequency for the DSP analyser.
If the measurement has been triggered, and no input signal is provided, an GPIB time-out
offers a convenient method for dissarming the DSP trigger and continuing the program. If
the mobile’s TX power falls outside +/-3dB of the expected value, measurement results
may not be valid. If the DSP analyser has not been able to find a good signal, or
synchronise to the burst midamble, the status message will warn of the problem. Dropped
calls and other problems are logged by the Agilent 8922M/S in an error message stack.
The messages can be queried to provide an indication of where problems have occurred
during test execution.
Read through example program 1 and look at the way the GPIB commands in "GPIB
Commands Used in Exercises" have been used to add robustness. Look for the “ERROR
AND TIMEOUT HANDLING” part of the program and the sections making DSP
measurements.