Filterless amplitude detection of multiphase sinusoidal waveforms

Presents a detection method where several symmetrical AC signals i.e., sinusoidal waveforms equal in amplitude and equally shifted in phase, are converted into a small-ripple DC signal proportional to the input-sinusoid amplitude. The method relies on appropriate summing and rectifying of the input waveforms. The essence of achieving small ripple of the output signal is that the input waveforms are dumped selectively, i.e., inside some phase intervals. Simple detector circuits based on this method are shown. The detectors, being filterless, are fast and respond to quick amplitude changes which may occur in a narrow time interval