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3-9
Verifying Performance
Understanding the Tests
Test 04: Signal
Generator 0.3
GMSK Modulation
Equipment Required (excluding Agilent 8922S)
HP/Agilent 8904A Option 001/002 Multifunction Synthesizer
Theory of the Test
The HP/Agilent 8904A is used to generate a 270.833 kHz clock and random data.
This drives the UUT RF generator to generate the 0.3 GMSK modulated signals
with random data. This signal is then analyzed by the UUT to assure that the
frequency and phase errors are correct.
If the UUT is an Agilent 8922S, clock and data signals are generated internally, and
the HP/Agilent 8904A is not used.
Things To Check In Case Of Problems
• This test should only be performed if the UUT analyzer is known to be accurate.
Run test #9 first if there is any question about the accuracy of the UUT analyzer.
• Even when the accuracy of the UUT analyzer is known, its specification is such
that this test still has a high degree of measurement uncertainty.
• A possibility to verify an instrument that fails this test may be to use a second
Agilent 8922M/S to analyze the signal or use the HP/Agilent 11836A 0.3 GMSK
measurement software. This software (and its associated hardware) has a lower
measurement uncertainty but is not currently supported with the Agilent 8922
Performance Tests software.
Test 05: Audio
Frequency
Generator
Equipment Required
HP/Agilent 3456AVoltmeter
HP/Agilent 8903BAudio Analyzer
HP/Agilent 8902AMeasuring Receiver
Theory of the Test
The UUT is set to generate audio signals at various levels and frequencies. The
voltmeter measures AC and DC level accuracy, the audio analyzer measures residual
distortion, and the measuring receiver measures frequency accuracy.
Things To Check In Case Of Problems
• The measuring receiver and the UUT should have their timebases locked to make
accurate frequency measurements.