Hello Again, I'm in the process of implementing the following circuit provided by Thomas Adamson from Electronic Communications. The diagram only shows solutions at block level, the blocks are fairly simple to implement with the exception of the ramp generator. I've come across a few ramp generator circuits online, but can't seem to find one that has ON / OFF functionality. Most appear to be uncontrolled (oscillating) or just have ON trigger function then after a predetermined time turn off. Is anyone aware of a circuit that can perform this function? Also of interest is the way this circuit performs, many online circuit diagrams involving PWM Demodulation involve converting to PAM - this involves summing the ramp waveform with a synchronous pulse and then clipping out the ramp - just leaving the PAM. This circuit appears to skip that step and just filter the ramp waveform - can anyone foresee any problems with this? Thanks for your help as always.