Waveform measuring device

Claim 1

A waveform measuring device comprising an A/D converter for converting an analog input signal into a digital output signal; memory means for storing the digital output signal from said A/D converter; first detecting means for operating on the analog input signal and for generating a present signal; a second detecting means for operating on the digital output signal from said A/D converter and for detecting among said digital output signal a first signal of a desired time remote from the present time, said second detecting means comprising shift register means for successively storing the digital output signal from said A/D converter, selector means for selecting among the digital output signal stored in said shift register means a desired signal component of selected values, and comparator means for comparing the desired signal component from said selector means and another signal of selected values, and for generating said first signal which is within a selected range of values; trigger signal means for generating a trigger signal in response to said present signal and to said first signal; and means responsive to said trigger signal and operating on the digital output signal stored in said memory means, for displaying in real time a waveform of said analog input signal corresponding to a desired interval of time, so that data in the digital output signal is utilized for waveform display control independent of the time required to store and read out the digital output signal in said memory means.