A-168-1

Pulsewidth Modulation Generator

Module A-168-1 is a pulsewidth modulation generator (PWM Module). It derives a rectangle signal with adjustable pulsewidth from an external triangle, sawtooth or sine wave. The external signal can be an LFO, VCO or any other signal with falling/rising slopes (e.g. ADSR). In addition the pulsewidth can be modulated by a CV signal (e.g. LFO or ADSR). The typical application is the generation of a rectangle signal with PWM from VCOs or LFOs which do not yet have this feature (e.g. A-110-4, A-145, A-147-2, A-143-4, A-143-9).

The module is equipped with these controls and in/output:

• Manual PW control (PW)
• PWM CV Input with attenuator (PWM)
• Signal input (In)
• Output with LED control (Out)
• Inverted Output with LED control (/Out)
• Internal trimming potentiometer for PW (is adjusted for symmetrical 50:50 rectangle when the manual PW control is at center position)
• Internal trimming potentiometer for PWM range (is adjusted so that the manual PW control covers the full PW range 0 ... 100%)
• The trimming potentiometers are required to adjust the module for best operation for signals with different DC offsets (e.g. unipolar/bipolar signals) and different signal levels.
• Normally the module is assigned to another module because the trimming potentiometer have to be readjusted when the input signal changes (unless the signals have nearly the same DC offset and level)

http://www.doepfer.de/a1681.htm