5Pulser Waveshaper by frijitz

"The most effective waveshapers are the radical ones that produce multiple peaks per input cycle. There have been a number of these designed over the years, of course, but most are fairly complicated circuits.

A while back I discovered that the LM3914 LED bar-graph display driver chip can run at very high frequencies -- crisp square pulses well above the audio range! Operation of this chip is quite simple. It is basically a stack of window comparators, which fire one at a time as the input signal increases. The total span of the comparators is set by an external voltage.

From this I figured out how to make an interesting waveshaper that puts out a variable pulse train. The waveshape control voltage changes the span of the comparators, so an input sawtooth leads to a train of pulses from a single square wave up to a train of five pulses in less than half a period as the control voltage is varied. (The more traditional wavefolders use a VCA on the input signal to vary the waveshape.) The circuit is quite simple for what it does -- a dual opamp for the input signal and CV conditioning, the LM3914 and an output opamp summer to combine the pulses."

Click here for more info including the schematic and a sample.