JPS57175275A - Delayed time measuring circuit - Google Patents

Abstract

PURPOSE:To realize the measurement of a delayed time with high accuracy and easy operation, by measuring the frequency or period of a pulse generating circuit at the time when the input and output pulse signals of a circuit part to be measured are synchronized with each other in phase. CONSTITUTION:The vertical signals supplied from vertical output signal terminals 13 and 14 of an oscilloscope 3 are supplied to an input part of voltage comparators 4 and 5 respectively. The comparison voltage VREF set at the other input part of the comparators 4 and 5 is set at the voltage value converted into a value corresponding to the threshold level value which is previously decided on the signal waveform on a screen 16. The output signals of the comparators 4 and 5 are equal to the pulse signals obtained by transmitting the signals oscillated from a voltage control oscillator 7 through a pulse generating circuit 2 and correspond to the signal waveforms at points A and B. These pulse signals are compared in phase through a phase comparator 6, and the loss or gain signal is transmitted to a VCO control circuit 8 to control the oscillator 7. The circuit 2 always delivers the pulse signal having a period equal to the delayed time between the points A and B. The signal periods of the circuit 2 are counted at that moment.