Posted on Apr 3, 2012 6260
This circuit for multiplying the width of incoming pulses by a factor greater or less than unity is simple to build and has the feature that the multiplying factor can be selected IYJ adjusting one potentiometer only. The multiplying factor is determined by setting the potentiometer in the feedback of the 741 amplifier. The input pulses e1, width T and repetition period Tis used to trigger a sawtooth generator at its rising edges to produce the waveform e2 having a peak value of E volts.
This peak value is then sampled by the input pulses~to generate the pulse train e3 having an average value of e4 ( = E rln which is proportional to T and independent on T. The de voltage e4 is amplified by a factor k and compared with sawtooth waveform e2 giving output pulses of duration kr. The circuit is capable of operating over the frequency range 10 kHz-100kHz. Note that k should be chosen less than TIT to ensure accurate pulse-width multiplication.