> Random equivalent-time sampling takes advantage of the nature of a repetitive signal by using samples from several trigger events to digitally reconstruct the waveform. Since sampling occurs on both sides of the trigger point, pretrigger capability is very flexible. Because repetitive signals are being sampled, the bandwidth of an equivalent-time scope can far exceed its sample rate.
Here's a more specific example: PicoScope 9400 series supports just 500Msps per channel, however it's advertising "70ps transition time and 1TS/s (1ps resolution) random equivalent-time sampling", this sort of "equivalent sampling" is presumably where that seemingly crazy spec comes from.
If you are an absolute nutcase, you could characterize a set of line stretchers and a multiplexer on a high end VNA then offset the inputs of the 4 channels on that UXR with them, take a capture and finally rebuild a 1TSamp/s signal out of the 4 results.
You have to have the 240V model of the scope to run all four channels at full rate (110GHz) though.
The older Tektronix TDS540 series did this, but at much lower rates as was common in those days though. Internally there are differential feeds from the very beautiful hybrid ceramic input boards to 4 DACs, with some clever switching so that a single input can be sampled by all 4 DACs with a suitable offset to create 4x the sample rate when running with all 4 inputs.
The calibration procedure on the scope fiddles with the time alignment to get the different DACs correctly offset so that the combined signal is correct.
The hybrid ceramic input boards in their metal cases are a thing of beauty, fragile (don't ask how I know), but beautiful.
Looks like max 50GS/s per their site. That also looks reasonable with the screenshot they have in the article showing 1ns / div horiz. But clarity on the data would be lovely. =)
Actually I take it back:
For the series 6B spec page...
Real-time: 50 GS/s (2 channels), 25 GS/s (4 channels), 12.5 GS/s (> 4 channels)
Interpolated: 2.5 TS/s
Typo? I didn't think we had sample rates anywhere near that high!
https://www.tek.com/en/documents/application-note/real-time-...
You have to have the 240V model of the scope to run all four channels at full rate (110GHz) though.
The calibration procedure on the scope fiddles with the time alignment to get the different DACs correctly offset so that the combined signal is correct.
The hybrid ceramic input boards in their metal cases are a thing of beauty, fragile (don't ask how I know), but beautiful.