Building Valve Amplifiers, 2nd Edition

Refresh rate

The screen’s refresh rate has to be fast enough (>80 Hz) for flicker not to be visible, but if the oscilloscope’s memory was only refreshed at this rate we might miss momentary glitches. Ideally, we would like every waveform capture to be followed by another at the first occurrence of the user’s trigger conditions being satisfied, and for all of this data to be written to display memory. In practice, some triggers and subsequent acquisitions may be missed because the oscilloscope’s memory system is not ready to accept data. Although refresh rate can be measured easily enough in terms of waveforms per second, it is hard to specify on a data sheet because it depends on time base setting, record length, triggering, and waveform ...