Bugs and tricks in PC DSOs and PC logic analyzers

[kormesii]

Anybody knows what is the max REAL sample rate and their Bandwidth of so called : PC DSOs ?
Some of then sells 200Ms/s PC-DSO and advirtise parameters like : repetetive sample rate - 10Gs/s. Has anybody use this feature ? I think this is just a advertisement - trick? The technique is simple but I think is useless.
I have used ANt8 logic analyzer that by specification can sample at 500 Ms/s but I was very displeased from it cause of a lot of noise and very small buffer. Actually their analyzer cann't be used for f > 50 MHz. Has anybody work with this model ?
I found some other PC analyzer and I was very surprised to see that they do nothing to reduce the noise !!!
I want to buy PC-DSO, but I'm interesting about some opinions about their bugs and real characteristics ?
It'll be very helpful for me to discuss here their bugs .
Regards

 

[Moss]

In most casses numbers a real. BUT you must understand what they mean. There is "single shot bandwith" and "analog bandwith" For exapmle look at specs of HP 54100. It is a 40MS/s 1 GHz analog bandwith scope. With such device is possible to look at any periodic signal with bandwith less than 1GHz. It is also possible to look high speed digital signals, but only so called "eye patern". For single shot signals bandwith is only 20 MHz. Very important is to make diference, between a frequency of signal and signal bandwith.