Abstract: A waveform comparison and display system using a cathode ray tube, which is provided with a digital memory function for sequentially storing input signal levels in digital quantities and re-reading them out under control of desired clock pulses and with a display function for displaying on the cathode ray tube two waveforms obtained in outputs produced by high-speed switching of the input signal and an analog signal re-read out. The storing operation and the sweep operation of the cathode ray tube are controlled by a trigger signal synchronized with the input signal. The generation of the clock pulses is start-stop controlled in synchronism with the sweep. Accordingly, the two waveforms are displayed on the screen of the cathode ray tube in such a manner that they are stationary with respect to each other.