公开(公告)号：US3876888A

公开(公告)日：1975-04-08

申请号：US34164273

申请日：1973-03-15

Applicant: WESTINGHOUSE ELECTRIC CORP

Inventor： GYUGYI LASZLO ,  STACEY ERIC J

IPC: H02M1/08 ,  H02M5/27 ,  H03K4/02 ,  H03K5/00

CPC classification number: H03K4/026

Abstract: An operational amplifier is used to synthesize a sine wave from a plurality of phase displaced rectangular waveforms of magnitude selected for minimum distortion. The rectangular waveforms are applied to the inverting (summing) input terminal of the operational amplifier while the non-inverting input terminal is maintained at a direct voltage resulting in an output of the synthesized rectangular waveforms that is symmetrical about the voltage level of the non-inverting input terminal. Application of this waveform to a simple first order filter, such as an integrator provided by a feedback network on the same opamp, results in a smooth sine wave of high precision suitable for various applications such as in cycloconverters.