I assume GP is talking about equivalent-time sampling. ETS is a technique for extending sampled system bandwidth at the expense of requiring a perfectly repetit

I assume GP is talking about equivalent-time sampling. ETS is a technique for extending sampled system bandwidth at the expense of requiring a perfectly repetitive waveform. Consequently, it's useless for single-shot captures, where you only get the native sample rate of the system. ETS used to be much more common in the days before (affordable) digital oscilloscopes could directly sample at high enough frequencies to be useful.