Sine signal generating circuit using pulse width and/or frequency adjustable, rectangular input signal - changes input signal scanning ratio after each preset number of periods to form first intermediate signal

摘要

The rectangular input signal (S1(t)) has its scanning ratio complementarily changed after a preset number of periods to form a first intermediate signal (S2(t)). The latter is passed through a low pass filter to obtain a sine signal (U). The circuit passes the input signal through a frequency divider (25). The divided signal changes its scanning ratio after each half-period, and a logic circuit (28) forms the complementary changed intermediate signal from the input signal. The low pass filter (31-33) contains a first stage (31, 32) for prefiltering the intermediate signal, obtaining a rectangular, second intermediate signal (S3(t)), and a second stage (33) for obtaining the sine signal from the second intermediate one. USE/ADVANTAGE - Maintaining sinusoidal waveform of power supply by simple digital control low-cost facility for signal frequency and amplitude adjustment as necessary.