User`s guide

2-13
GPIB Tutorial and Examples
Example E - Faster Testing
Example program 3 uses the Agilent 8922M/S Aux RF Out port to simulate a mobile
operating in a test mode. Mobiles controlled in test modes react much faster to channel
and TX Level change commands.
❒ Delays associated with the GSM SACCH and FACCH are removed.
❒ Measurements are made with no signalling overhead time.
The time savings made in programs 2 and 3 have been almost completely during the TX
part of the test. Improving the RX bit error ratio test time would speed-up each of the
programs. As TX test times reduce, RX tests appear to take up a larger percentage of the
overall test time. Techniques for improving RX measurement times include:
❒ Take RXQual as a first indication of receiver performance. Perform bit error test only
if RX Qual is poor.
❒ Reduce the number of bits being tested and reduce the signal level from -102dBm to a
lower level. This will increase the number of bit errors in the reduced measurement
period to maintain a statistically valid test.
❒ Look for zero bit errors at -102dBm over a reduced number of bits. Use a longer
measurement only if bit errors are detected.