The "5-Pulser" waveshaper produces a train of pulses whose number (and widths) are varied with a control voltage. At the lowest control voltage a single square wave is put out, whereas at the highest voltage a train of 5 pulses spanning less than half of the total wave period is produced.

The input signal should be, ideally, a 0V to 5V sawtooth. 

A demonstration of the 5-Pulser by Ian fritz