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Performance Verification
AM700 Audio Measurement Set Service Manual
4–29
Figure 4–17: FFT Analyzer Window menu display
8. Check that the noise floor is below –120 dBu.
1. Set the High Resolution generator to an amplitude of 0 dBu and a frequency
of 1 kHz.
2. Looking at the generator output with the High Resolution FFT, check to see
that any harmonics of the fundamental are –85 dB or lower relative to the
fundamental. The third harmonic may be worse than the second harmonic,
but it is typically –90 dBu or lower relative to the fundamental.
3. Press the Control button in the Generator controls area of the front panel.
Touch the Advanced Analog Controls soft key.
4. Turn on the High Resolution Distortion Reduction mode of the generator and
observe that the distortion products and the noise floor diminish.
5. Turn off the High Resolution Distortion Reduction mode.
1. Disconnect the generator from the inputs to the measurement channels.
2. Set the input impedance for 600 W.
3. Check that the noise floor of the FFT display is always below –120 dBu and
mostly below –130 dBu.
Check Harmonic Content
Check Acquisition Noise
Floor