Posted on Feb 6, 2014

This was originally developed a timing accessory for a sequencer I was working on, though when fed from a VCO, interesting frequency trills like those of the old 8-bit computer games can be produced. Feeding the control voltage from a Psycho LFO produces some interesting effects. There are two outputs, one a narrow `trigger` pulse, the other follo

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wing the pulse width of the incoming signal. This means that any mark/space ratio sweep being applied to a VCO connected to this module, will also be on the output signal of this module. Connect the input to a signal source such as a VCO, LFO or sequencer master clock. Use the control voltage input to determine the number of incoming pulses per output pulse. There are two pulse outputs, marked HO and LO on the PCB. HO (High Frequency out) gives a narrow trigger pulse output. LO (Low Frequency out) gives a pulse output, the width of which varies with the pulse width of the incoming signal. Depending on the individual ICs you use, the propagation delays of the chips will limit the speed at which the LO output can function. I estimate it drops out above 10 kHz, though as mentioned, it does vary with individual 40106 chips. The circuitry around IC1B processes the incoming frequency, and squares up the waveform so it is suitable for the digital portions of the circuit. It drives the counter (4024) and sets the output flip-flop based around two portions of the 40106. This block is fed via a DC mixer stage which includes both inverting and non-inverting inputs, as well as a DC offset allowing for easy adjustment of the "sweet spot" for the incoming signal. The mixer also has an output making the unit a handy utility module even when you are not doing any dividing. The output of the counter (4024) is connected to a D to A converter...

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