Tektronix TDS1000B Series Operator's Manual page 23

Digital Oscilloscopes
In contrast to analog oscilloscopes, digital oscilloscopes use
an analog-to-digital converter (ADC). An ADC converts the
voltage being measured into a digital format. A digital
oscilloscope acquires a waveform as a series of signal
samples, which are stored in its memory and then
reassembled for viewing on the screen.
Digital oscilloscopes are categorized into two types, digital
storage oscilloscopes (DSO) and digital phosphor
oscilloscopes (DPO). Let us look at how these two types of
digital oscilloscopes work.
TDS1000B and TDS2000B Series Oscilloscopes – Operator Training Kit
Introduction to Oscilloscopes and Probes
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