The PREAMP and DETECTOR cirucits do not require any calibration.
The following steps adjuste the points at which the PEAK and ENVELOPE LEVEL indicators operate.
PEAK Indicator (CLIPPING)
- Patch a 440Hz 200mVAC sine wave into [Hi-Z IN].
- Monitor [PREAMP OUT] and adjust [GAIN] for a level of 5.5VAC
- Set P1 fully counter-clockwise
- Adjust P1 until the LED just turns OFF
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ENVELOPE LEVEL
You will need an envelope generate and a VCA with logarithmic control input to generate an amplitude modulated signal.
- Set the envelope generator to output a fast rising 4Hz 5VDC sawtooth
- Patch the sawtooth into the LOG input of the VCA
- Patch a 2kHz 5VAC sine wave into the AC input of a VCA
- Patch the VCA output into the [IN] input of the Detector
- Set the [COUPLE] switch off (up)
- On a dual trace scope display the [ENVELOPE] output
and the original sawtooth. Note that both of these displays are
of CVs and are not audio
- Now, while monitoring the scope, adjust the VCA's gain
control knob so that the two traces look almost exactly alike
Adjust P1 so that intensity of the LED follows the [ENVELOPE] output and is extinguished when the envelope is close to zero |
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