True, the LeCroy I have has +/- trigger, which is sometimes invaluable and very hard to emulate if your scope does not have that feature.
Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -----Original Message----- From: Tom Knox <act...@hotmail.com> Date: Tue, 17 Apr 2012 08:33:35 To: <shali...@gmail.com> Subject: RE: [time-nuts] Chinese Scopes I also like the LeCroy I have because of the deep memory, but I also find the advanced trigger options are equally important in capturing many events. Thomas Knox > To: j...@quikus.com; time-nuts@febo.com > From: shali...@gmail.com > Date: Tue, 17 Apr 2012 13:56:43 +0000 > Subject: Re: [time-nuts] Chinese Scopes > > 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. _______________________________________________ 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.