Phase‐shift generation and monitoring by a simple circuit

A simple circuit for generating phase shifts along with a monitoring scheme is described. The circuit reported here produces a squarewave signal with fixed phase shift relative to the incoming signal. The amount of this phase shift can be monitored by the input voltage of a voltage‐controlled oscillator. By varying the free‐running frequency of the voltage‐controlled oscillator the phase shift of the output signal can be varied for a range of 0°–180° corresponding to a voltage change of −1.2 to 1.2 V. The produced phase shift is a linear function of the voltage setting that can be controlled with a high accuracy. The reported circuit can be used in phase sensitive detection systems operating based on a shifted squarewave reference signal.