Crown FM30 - Audio Frequency Response; Audio Distortion; Modulation Percentage; FM and AM Noise

5–9
Adjustments and Tests
5.14 Audio Frequency Response
For the response tests, take the readings from an FM modulation monitor.
Make audio frequency response measurements for left and right channels at
frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See
sections 5.9.1 and 5.9.2.
5.15 Audio Distortion
Make distortion measurements from the de-emphasized output of an FM
modulation monitor.
Make audio distortion measurements for left and right channels at frequencies of
50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See sections 5.9.1 and
5.9.2.
5.16 Modulation Percentage
While feeding an audio signal into the left channel only, confirm that the total
modulation percentage remains constant when switching between Mono and
Stereo.
Measure modulation percentage with an FM modulation monitor.
See section 5.2.2.
19–kHz pilot modulation should be 9%.
5.17 FM and AM Noise
Take noise readings from a de-emphasized output of a modulation monitor.
5.18 Stereo Separation
Make left-into-right and right-into-left stereo separation measurements with an
FM modulation monitor for frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz,
10 kHz, and 15 kHz.
5.19 Crosstalk
For stereo crosstalk measurements, both left and right channels are fed at the
same time. For best results, there needs to be a means of correcting small
imbalances in levels and phase. The balance is made at 400 Hz.