General > General Technical Chat
Is this product a BS didn't it?
Marco:
--- Quote from: EEVblog on October 18, 2021, 11:07:19 am ---Kinda sounds like it might not be a real high speed ADC measurement, but more of an implied result based on comparator threshold measurements maybe?
At the claimed 12.8GHz you'd need some insanely fast ADC stuff to get a real time eye diagram. I'm not seeing that capability on that board.
--- End quote ---
An ultrafast comparator with fast latching can do the equivalent of ADC on a repetetive signal. Equivalent equivalent time sampling so to say :)
BrianHG:
Speaking of repetitive sampling techniques on a fixed pattern generator, don't ADCs exist, not necessarily too high a sampling frequency, but, a super small sample-and-hold gate at the input down in the 100ps range? All you need is a 100-200MHz sampling rate, but, a ~100ps sample-and-hold. In fact, the sample and hold may also be an external stand-alone IC.
Marco:
The only advantage over the dac+comparator approach is speed, which is not all that important. Not worth paying the 100x boutique price multiplier for.
langwadt:
--- Quote from: BrianHG on October 18, 2021, 05:18:28 pm ---Speaking of repetitive sampling techniques on a fixed pattern generator, don't ADCs exist, not necessarily too high a sampling frequency, but, a super small sample-and-hold gate at the input down in the 100ps range? All you need is a 100-200MHz sampling rate, but, a ~100ps sample-and-hold. In fact, the sample and hold may also be an external stand-alone IC.
--- End quote ---
you can get plenty of ADCs with far higher analog bandwidth and sample-hold than sample rate, so they can be used for subsampling, but once you get to GHz they get expensive
https://hackaday.io/project/167292-8-ghz-sampling-oscilloscope
Sal Ammoniac:
--- Quote from: Bassman59 on October 17, 2021, 10:53:44 pm ---TotalPhase products are solid.
--- End quote ---
I would agree that their hardware is generally solid, but their software often leaves much to be desired. I have one of their instruments, and the software application that goes with it crashes after 2-3 days of collecting data. Since I use this device to debug intermittent issues that occur infrequently, this makes it useless. I reported this issue to the company years ago, but it still hasn't been fixed.
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