Digital Oscilloscope: Waveform Stored in Memory and Shown on a CRT (Schumann, Nicolet, US 3,816,815, 1974)

An oscilloscope with a memory. After a trigger, an analog-to-digital converter measures the input at regular intervals and writes each reading into its own memory register, replacing the old one. The screen then shows the memory: each register's number sets the beam's height, its address sets the beam's place across. The last waveform can be held on the screen as long as you like. Result: a digital storage oscilloscope with 4,096 points of 12 bits, refresh and hold modes and single-shot capture. Source: R. W. Schumann (Nicolet), US 3,816,815 (1974). Unknown: sample rate, bandwidth, voltages and the parts used. Picture: the patent drawing.