Waveform observing method and apparatus

A waveform display apparatus, comprising:

• a timebase circuit for generating a slow ramp signal, a fast ramp signal in synchronism with a repetitive signal to be displayed, and strobe pulses in response to the fast ramp signal successively passing through the instantaneous voltage of said slow ramp signal;
• a digital-to-analog converter for producing an analog output-signal, the amplitude of which is proportional to the number of slow ramp signals;
• a comparator for comparing said analog output signal with said repetitive signal to be displayed to generate control signals thereby, said comparator operating in response to said strobe pulses;
• and
• a cathode-ray tube including orthogonal deflecting means for deflecting the electron beam thereof in response to said slow ramp signal and said analog output signal, said cathode-ray tube further including beam intensity control means responsive to said control signals.

A method for displaying the waveform of a repetitive input signal, comprising the steps of:

• generating a first signal, the amplitude of which increases slowly with time;
• generating a second signal in synchronism with said repetitive input signal, the amplitude of said second signal increasing linearly with time at a rate substantially faster than that of said first signal;
• generating strobe pulses by comparing said second signal with said first signal;
• producing an analog signal, the amplitude of which is proportional to the number of cycles of said first signal;
• generating write control signals coincident with said strobe pulses by comparing the amplitude of said analog signal with said repetitive input signal;
• and
• producing a graphic display of the waveform of said repetitive signal in response to said write control signals, wherein said first signal is utilized to provide deflection along a first display axis and said analog signal is utilized to provide deflection along a second display axis.