Summary: Phase-shift generation and monitoring by a simple circuit
H. Golnabi and A. Ashrafi
Institute of Water and Energy, Sharif University of Technology, P.O. Box 11365-8639, Tehran, Iran
Received 23 May 1995; accepted for publication 24 January 1996
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. © 1996 American Institute of Physics.
S0034-6748 96 04304-3
In many applications such as lock-in amplifiers a phase
shifter is required in order to produce a reference triggering
The first consideration may be the use of a
simple RC circuit to shift the phase. There are two major
problems in using such circuits with the discrete elements.