JPS6483174A - Detecting device of phase - Google Patents

Abstract

PURPOSE:To obtain a detecting device keeping a highly precise amplitude balance automatically, by providing a phase detector, a local oscillator, a phase shifter, an A/D converter, a divider, a hole circuit, a multiplier, etc. CONSTITUTION:A phase detector 1 subjects an input IF signal to phase comparison with a reference signal output of a local oscilator 2 and detects and outputs two orthogonal components. The phase shifter 3 shifts the phase of the reference signal output of the oscillator 2 at every pi/4m (m is an integer) according to a phase switching signal and generates a pilot signal for detecting imbalance of amplitude. A/D converters 4a and 4b quantize detection outputs of the detector 1. A delay circuit 5 delays a cos component by a time in which the phase of the pilot signal changes at pi/2, and a divider 6 divides the cos component by a sin component for detecting the imbalance of the amplitude. A hold circuit 7 holds an input value except for a period in which the pilot signal is injected, and a multiplier 8 multiplies the imbalance by the sin component to correct the same. Besides, a switch 9 switches over the input signal and the pilot signal.