Modulator based on electronic change of phase shift in simple oscillator

In this study, we propose phase shift keying system using an oscillator based on two all-pass filters. The main idea is based on phase commutation by converted data to two pairs of DC control voltages for controlling both all-pass sections. Therefore, the proposal of converter of data to DC control voltages is solved with precise amplitude automatic gain control circuit. The system operation was verified while employing commercially available devices through PSPICE program at the modulation frequencies 1 MHz and 10 kHz with driving signals 0 V (L) and 5 V (H), respectively. The simulation results confirmed the theoretical presumptions.