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Performance Verification
AM700 Audio Measurement Set Service Manual
4–15
5. Touch the Advanced Analog Controls icon to display the screen shown
previously in Figure 4–8.
6. Select High Resolution Distortion Reduction mode for Channel A and
Channel B. The selection indicator box is checked when selected.
7. Check that the Channel A and Channel B THD + N reduces to approxi-
mately 0.0025%.
8. Turn off Low Distortion Mode for Ch A and Ch B.
1. Press the Generator Control button.
2. Touch the High Bandwidth box under Generator selection (see Figure 4–4 on
page 4–8.
3. Touch Waveform Control.
4. Select the Analog A generator for edit if not already selected. Set Analog A
to Sine, Frequency to 1 kHz (you will see 0.996 kHz), and Amplitude to
3.5 V. Make sure that the Analog A Generator output is on.
5. Check the RMS amplitude at 1 kHz with the RMS meter.
6. Check the THD + N at 1 kHz for a reading of 0.01% or less using the
distortion analyzer.
7. Set the generator frequency to 9 kHz.
8. Check the frequency accuracy is within 0.01% (8999.1 to 9000.9) with the
frequency counter.
9. Set the frequency and amplitude to the values shown in Table 4–4 and check
the amplitude accuracy with the external RMS meter. At 117.1 Hz (this is as
close to 120 Hz as the setting resolution of the high bandwidth generator
permits), the measured values should not differ by more than approximately
1.5% (approximately 0.15 dB) from the set value at signal input levels from
+13.9 dBu down to –34.1 dBu. At input signal levels from less than
–34.1 dBu to –52.1 dBu, the amplitude accuracy at 120 Hz should be within
±0.25 dB (approximately ±2.5%).
At 11.719 Hz and 20 kHz, the measured amplitude values should not deviate
from the 117.1 Hz measured values by more than +1%. At 80 kHz the
measured amplitude values should not deviate from the 117.1 Hz measured
values by more than +5% to –10% (typically this will be near –5%). At
70 kHz, the typical amplitude accuracy is near –3%.
Check High Bandwidth
Generator