IMO, memory depth is like trying to do CAD on a standard computer monitor... you keep having to switch between the local and global views to do really anything. I find it annoying in the extreme.
IMO, you need enough memory depth so that you don't get artifacts, like those in the pics I posted. No 465 would mess up the waveform that way, and remember, that was of a LORAN-A pulse for a system that was designed before most of us were born and that ceased operation over 40 years ago... not a current design. -John ================ > I agree that memory depth is an under appreciated parameter, but even > 2,500 points like what's available on the cheap Tek scopes is quite > useful. > > On the other hand, I had a few LeCroy with 50k deep memories and there are > cases where that is very useful too. I can't imagine real life use cases > when I would need multiple MB. It would be nice to have but seldom used. > > One issue is that most DSOs don't have displays that let you take > advantage of the higher memory depth other than by letting you zoom in on > a narrow time window. I have found that on the TDS 200 and 2000 series, > downloading the data to a PC will let you display and print higher > resolution pictures and I wrote a utility to do that. > > Didier KO4BB > > Sent from my BlackBerry Wireless thingy while I do other things... > > -----Original Message----- > From: "J. Forster" <j...@quikus.com> > Sender: time-nuts-boun...@febo.com > Date: Mon, 16 Apr 2012 13:58:09 > To: Discussion of precise time and frequency > measurement<time-nuts@febo.com> > Reply-To: j...@quikus.com, Discussion of precise time and frequency > measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] Chinese Scopes > > OK. IMO, there is another, perhas a more important, issue.... memory > depth. > > Most digital scopes I've seen, and some LAs too, just don't have enough > depth for my taste, so they undersample and guess. > > Tek did make the RTD-710A high speed transient data digitizer that had 64 > MB of 12 (?) bit RAM. That is beginning to be useful, IMO. > > -John > > ================== > > >> Sorry john, that's more what I meant, by accuracy and precision I imply >> its faithful to the signal you choose to examine, free of artifacts >> induced by the scopes timebase or vertical amp, but with DSOs its >> limited >> by Nyquist sampling rules. >> >> Thus, sampling rate is as important a feature as a scopes rated >> bandwidth. >> For best results, its should be 10x the analog bandwidth. Below it, >> one >> has to beware of artifacts, it worsens as the ratio signal bandwidth/ >> sampling rate < 10. >> >> >> At 14:32 04/16/2012, time-nuts-requ...@febo.com wrote: >> ------------------------------ >> Message: 2 >> Date: Mon, 16 Apr 2012 10:59:16 -0700 (PDT) >> From: "J. Forster" <j...@quikus.com> >> To: "Discussion of precise time and frequency measurement" >> <time-nuts@febo.com> >> Subject: Re: [time-nuts] Chinese Scopes (was: Re: LORAN-C at MIT) >> Message-ID: <56387.12.6.201.2.1334599156.squir...@popaccts.quikus.com> >> Content-Type: text/plain;charset=iso-8859-1 >> >>> At eevblog.com forum Chinese scopes are a daily discussion for over 3 >>> years. >>> >>> In summary, in the <= 100 MHz level they are ... >> ...snip... >>>... less. The criteria for rating them are >>> measurement accuracy and precision, UI, construction quality and tech >>> support. >> >> Measurement accuracy is a ruse, IMO. I don't care if a 'scope is >> "accurate". I want the waveform to be a faithful representation of the >> electrical behaviour of the circuit, free oif sampling artifacts and >> aliasing. >> >> If I want to accurately measure a voltage, I'll use a differential >> comparator or DVM. Anything timing, an appropriately gated counter. >> >> Some years ago Tektronix had a digital camera package with RS-170 output >> and some aardvaark frame grab board for a PC and a SW package. It was >> designed to do waveform measurement. >> >> I would actually like to know why many seem to feel that a 500 MHz >> analog >> 'scope is not "good enough" for what you really do in your lab? >> >> The more I hear about 40 GSps or whatever 'scopes, the more I'm >> convinced >> it's like comparing car engines or top speed. So, I have a car that'll >> do >> 160 MPH and yours will do 172? So what? Can you use it? No. >> >> YMMV, >> >> -John >> >> >> Best Wishes, >> >> >> Marv Gozum, Philadelphia Pa >> >> [ sent via Outlook webApp] >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.