Logic pulse train conversion to unity mark space ratio - using rc integrator and with output supplied to inverting and non-inverting inputs of amplifier comparator via low pass filter and directly

摘要

Conversion of logic signal pulse trains having a wide range of mark-space ratios to a 1:1 ratio. The conversion circuit is esp. applicable to clock signals where accurate spacing of leading and trailing edge is important. The circuit is based on an RC integrator (3) providing a saw-tooth waveform from the incoming pulse train (1) which is fed to the non-inverting input of an operational amplifier (10) acting as a comparator and to a low pass filter (11). he filter supplies the amplifier inverting input with the sawtooth signal mean value. The integration constant of the RC network provides highly linear sawtooth rise and fall slopes, the DC component of its output being blocked by a capacitor from the RC junction.