I would agree that a DSO with a peak detect mode is the way to go for general purpose work. I just wish the cheap ones had delayed sweep and faster waveform acquisition rates instead of long record lengths.
When I was diagnosing an offline switching power supply a few weeks ago that was stuck in pulse mode, digital storage mode on my Tektronix 2230 saved the day. On Thu, 19 Apr 2012 21:54:16 +0000, shali...@gmail.com wrote: >"A non-sampling oscilloscope with limited bandwidth could just as easily >miss a narrow pulse because of bandwidth constraints no matter how >high its sampling rate." > >That is the point of the thread. Even a wide bandwidth analog scope used to >show a 500nS pulse at a 200Hz repetition rate will have a hard time, while any >DSO worth the name will have no problem with it. > >Didier KO4BB > >Sent from my BlackBerry Wireless thingy while I do other things... > >-----Original Message----- >From: David <davidwh...@gmail.com> >Sender: time-nuts-boun...@febo.com >Date: Wed, 18 Apr 2012 18:11:29 >To: Discussion of precise time and frequency measurement<time-nuts@febo.com> >Reply-To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> >Subject: Re: [time-nuts] Rigol scopes > >On Wed, 18 Apr 2012 13:56:18 +0000, shali...@gmail.com wrote: > >>That's why the default mode for a DSO should always be "pulse detect" or >>whatever the manufacturer calls it, unless you know what you are doing. As >>far as I know, all DSOs have this or an equivalent mode where the ADC runs at >>full speed regardless of sweep speed, and the min and max readings between >>two display points are stored. If you are in a condition that would otherwise >>result in aliasing, the trace will look like a big fat trace, just like on an >>analog scope if you are probing a 10MHz signal at 1mS/div. > >Do the low end Rigol oscilloscopes actually support peak detection? >The manual only describes an envelope mode without any ability to set >the number of envelopes like a Tektronix 2440 can for single shot peak >detection. When I was in the market for a DSO a couple years ago, the >Rigol representatives could not answer. I ended up rebuilding an old >Tektronix 2230. > >>You get the same issue with an analog sampling scope, except that those don't >>have a "pulse detect" mode, so they WILL lie to you unless you know what you >>are doing. It is not a "digital storage" issue, it is a sampling issue. > >Sampling oscilloscopes are in a class all to their own and very >specialized. Their low sample rates hinder capturing infrequent >events but if a repetitive glitch is there, they can still see it. A >non-sampling oscilloscope with limited bandwidth could just as easily >miss a narrow pulse because of bandwidth constraints no matter how >high its sampling rate. > >_______________________________________________ >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.
