Oscilloscope: Two-Channel Digital, with a Delay per Channel and a Common Delay (Anritsu, US 4,727,288, 1988)

A two-channel digital oscilloscope. Each channel has its own converter and delay circuit. One knob, with a main and a sub button, sets the delays. The sub button shifts only the sub channel's wave, so you can line it up against the main one. The main button shifts both waves together and keeps the gap between them. Result: a 2-channel digital oscilloscope that can move both traces along the time base without losing their phase difference. Source: K. Nakatsugawa et al. (Anritsu), US 4,727,288 (1988). Unknown: sample rate, bandwidth, memory size and the display. Picture: the patent drawing.