 Sample rate is the sample frequency of the oscilloscope, namely the waveform points
sampled per second.
 The following equation describes the relationship among memory depth, sample
rate, and waveform length:
Memory Depth = Sample Rate x Waveform Length
Wherein, the Memory Depth can be set using the :ACQuire:MDEPth command, and
the Waveform Length is the product of the horizontal timebase (set by
the :TIMebase[:MAIN]:SCALe command) times the number of the horizontal scales
(12 for MSO1000Z/DS1000Z).