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Performance Verification
4–12
AM700 Audio Measurement Set Service Manual
13. Repeat the checks of step 10 and step 11 for the Analog B generator. To
change the frequency and amplitude of the Analog B generator, press the
Control button in the Generator front-panel control section. Touch the
Waveform Controls icon; then Touch the Analog B soft key. The Amplitude
and Frequency edit boxes will now control the Analog B generator output.
These checks verify the functionality of the analog generator at a low, a mid, and
a high frequency at each attenuator step.
1. Make the analog generator initial settings.
a. Set Units to volts to match the digital voltage meter.
b. Voltage settings 2.000 V rms
c. Initial Frequency setting 120 Hz
d. Make sure the generator is still in High Res Mode.
e. Set the signal to sine wave.
f. Set the Ch B generator to Sine (not Follow A) so Ch A and Ch B are
checked independently.
g. Touch the Advanced Analog Controls icon and set the output impedance
to 10 W (see Figure 4–8). Set the output impedance by touching the
Output Impedance edit box to display a popup menu of the choice. Turn
the main control knob to select 10 W and touch the edit box again or
press the Enter key in the key pad to make the selection.
2. Check the RMS voltage with the RMS meter at 120 Hz. These are the
reference values. RMS amplitude accuracies at other frequencies are
measured with respect to those measured at 120 Hz.
The specification for amplitude accuracy at 120 Hz with signal amplitudes
from +13.9 dBu to –16.1 dBu is ±0.1 dB (typically within ±0.05 dB). From
less than –16.1 dBu to –34.1 dBu it is ±0.15 dB (typically within ±0.1 dB).
For signal input amplitudes less that –34.1 dBu down to –52.1 dBu, the
amplitude accuracy is ±0.25 dB
3. Disconnect the test cable from the Analog A generator output and connect
the BNC to XLR female adapter cable between the Analog A output and the
frequency counter. The cable wiring is shown in Figure 4–9.
Analog Generator Check