Abstract: A waveform memory circuit samples an analog waveform at regular intervals to generate and store in a first random access memory digitally encoded data points representing the waveform magnitude. Only data points minimally different in magnitude from the most recently stored data point are stored. The number of sampling periods between successively stored data points is counted and stored in a second random access memory. Provisions are made for external control over data acquisition cycle start, the number of data points to be stored, sampling frequency, and difference minimum required to initiate storage.