JPS6418308A - Phase difference control device - Google Patents

Abstract

PURPOSE:To apply phase shift control to the phase of an input signal in the accuracy of <=1 bit simply with high accuracy by connecting directly a phase difference control module comprising a voltage controlled phase shifter and a buffer amplifier, etc., in one-stage or multi-stage. CONSTITUTION:The phase difference control module 2 is basically made up of a voltage controlled phase shifter 3 shifting the phase of an input clock signal in response to the control signal, a buffer amplifier 4 waveform-shaping the output signal, a phase comparator 5 and an operational amplifier (feedback control circuit) 6. Since the phase shift with respect to the input signal is controlled via the voltage controlled phase shifter 3, the stable phase control is applied regardless of the temperature change or dispersion in the device components and independently of the frequency of the input signal. As a result, even if a delay of the accuracy less than one bit time is given to the input signal, the delay (phase shift quantity) is controlled simply with high accuracy. Moreover, the modules 2 are connected in multi-stage directly, then the phase shift is set programmably with high accuracy and high stability.