The Tektronix 390AD is a digitizer with a 15 MHz bandwidth and a GPIB interface, released in the early 1980s.
It can digitize two channels at up to 30 MS/s or one channel at up to 60 MS/s, at 10 bits of voltage resolution.
Dynamic accuracy is 8.5 bits up to 1 MHz and 7.5 bits up to 10 MHz. The memory is 4096 samples, which can be used for digitizing a single waveform or for two waveforms at 2048 samples each.
The 390AD has a "Rate Switching" feature where it starts an acquisition at one sample rate, and then switches to a second sample rate. The 390AD can be set to trigger from either of the two vertical signals or from an external trigger signal.
The signals acquired on a 390AD can be exported via GPIB or displayed on an external CRT (Tek 624 is recommended) in X-Y mode.