Abstract: Phase is important parameter for analyzing electrical signals． Usually the output of the phase
measurement circuit is based on absolute phase difference． This nonlinear input-output relationship makes it
difficult to realize high stability and low cost hardware circuit． A linear phase detection circuit is designed by
using operational amplifier and ＲS ( Ｒeset Set) flip-flop to realize the function of shaping and triggering the edge
of the double sinusoidal signal． Using operational amplifier LM6144，the mean deviation is less than 0． 3° when
the test signal frequency is less than 100 kHz． The design defect of nonlinear phase detection is solved．

Key words: phase measurement, voltage-current convert, operational amplifier