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Verifying Performance
Understanding the Tests
Test 06: Audio
Frequency Analyzer
Equipment Required
HP/Agilent 8904A Option 001/002Multifunction Synthesizer
HP/Agilent 3456AVoltmeter
Theory of the Test
The HP/Agilent 8904A is used to generate accurate test signals which are analyzed
by the UUT. The voltmeter is used to reduce measurement uncertainty by accurately
characterizing the test signal level to predict the correct response of the UUT. The
voltmeter is used in the AC level, DC level, SINAD and distortion measurements.
Distortion test signals are generated by summing two sinewaves in the HP/Agilent
8904A, one as the desired signal, the other as a distortion product.
Things To Check In Case Of Problems
• For frequency accuracy measurementsthe HP/Agilent 8904A timebase should be
locked to the UUT.
• The voltmeter reading is used as a reference to normalize the reading from the
UUT. The output “measured” result is the actual reading from the UUT
normalized by the actual reading from the voltmeter. If the voltmeter makes a
faulty reading, it will normalize the actual UUT response and cause it to appear
faulty also. If the front panel reading from the UUT is significantly different from
the printed “measured” response, the normalization may be the cause.
Test 07: Oscilloscope Equipment Required
HP/Agilent 8903BAudio Analyzer
HP/Agilent 3456AVoltmeter
Theory of the Test
The audio analyzer is used to generate CW reference signals which are
characterized by the voltmeter and fed into the UUT. The voltmeter reading is used
to normalize the reading from the UUT oscilloscope. The oscilloscope
measurements are taken using the UUT marker function which is set to the peak of
the input sinewave.
Things To Check In Case Of Problems
• The voltmeter reading is used as a reference to normalize the reading from the
UUT. The output “measured” result is the actual reading from the UUT
normalized by the actual reading from the voltmeter. If the voltmeter makes a
faulty reading, it will normalize the actual UUT response and cause it to appear