Turn your Rigol DS1052E Oscilloscope into a 100MHz DS1102E
in [Design]
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From: The Phantom on 9 Apr 2010 23:36 On Fri, 09 Apr 2010 08:33:23 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On 9 Apr 2010 03:46:01 -0500, The Phantom <phantom(a)aol.com> wrote: > >>On Thu, 08 Apr 2010 17:36:30 -0500, "krw(a)att.bizzzzzzzzzzzz" >><krw(a)att.bizzzzzzzzzzzz> wrote: >> >>>On 8 Apr 2010 14:14:01 -0500, The Phantom <phantom(a)aol.com> wrote: >>> >>>>On Thu, 08 Apr 2010 17:06:06 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> >>>>wrote: >>>> >>>>>On a sunny day (Thu, 8 Apr 2010 08:57:53 -0700 (PDT)) it happened brent >>>>><bulegoge(a)columbus.rr.com> wrote in >>>>><fb2980a4-6e02-48db-b20d-57eefa8df2a6(a)v8g2000vbh.googlegroups.com>: >>>>> >>>>>>On Apr 8, 10:01�am, John Larkin >>>>>beep BAD SYNTAX >>>>> >>>>>>> I can't think of much. Maybe clean X-Y plots; the digitals are sloppy >>>>>>> in X-Y mode. >>>>>>> >>>>>>> ftp://jjlarkin.lmi.net/Hills.JPG >>>>>>> >>>>>>> John >>>>>> >>>>>>When I am looking at video signals with higher power RF signals on the >>>>>>board I will take an analog scope any day. >>>>> >>>>>I agree, for video an analog scope is great. >>>>>In fact the *ONLY* reason for digital is storage, >>>>>and even then good analog storage scope once existed. >>>> >>>>I can think of a particular aspect of digital storage that, AFAIK, analog >>>>storage can't do. With digital storage, one can examine the signal BEFORE the >>>>trigger point. Has there ever been an analog storage scope that could do that? >>> >>>Sure. Have you ever heard of delay lines? Also, delaying timebases were >>>commonly used to look "before" the trigger event. >> >>Please explain how a delaying timebase could allow one to see events before (and >>I mean much more than a delay line's worth of "before") the trigger event if the >>trigger event is a one-shot event; no periodic waveforms involved. > > >He probably refers to zooming in on the next recurrence of a periodic >waveform. That's why I asked how it would work with a non-periodic waveform (one-shot, in other words). Modern digital scopes have no problem with such a situation. See my example in ABSE. >But signal period jitter and scope delaying timebase jitter >can be nasty. Classic delayed sweeps and sampling scope timebases run >in the ballpark of one part jitter in 20,000 to 50,000 of the delay >time. > >John >
From: The Phantom on 9 Apr 2010 23:39 On Fri, 09 Apr 2010 08:27:49 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 8 Apr 2010 22:26:29 -0500, "Tim Williams" ><tmoranwms(a)charter.net> wrote: > >>"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>news:ks6tr5h4k5jv51n0lp1is4hrs537v1rmse(a)4ax.com... >>> Delay lines can't store milliseconds of pre-trigger data. The best >>> they do is let you see a few ns of pre-trigger waveform. >> >>John John John, >> >>That's what entire spools of foamed teflon coax are for! ;-) >> >>Man, I can just imagine how many hours of cocaine you could buy for the >>price of a few microseconds of that sort of stuff. Seems kind of >>disappointing. >> >>Tim > >It's hard to store much information in an electromagnetic delay line. >The losses kill you. > >It would be an interesting calculation to see how many bits you could >store in any preferred length of, say, RG58. To store the equivalent of an Agilent 6000 series 8 Mbyte trace memory would take miles of coax; many miles. > >Fiber is a different story. You can stuff gigabits per second into a >hundred kilometers of single-mode fiber and recover it perfectly. > >But RAM is a more sensible way to store information. > >We have a couple of spools, or rigid coils actually, of half-inch >hardline coax in our lab, 50 ns ballpark. They make handy zero-jitter >pretrigger delays for sampling scope situations. But the pulse that >comes out the end is clearly degraded from what goes in. > >We also have a couple of Tek 7M11 delay-line plugins, which can be >used standalone. It's dual-channel, 75 ns per, 2 GHz bw. They give up >half the signal so that they can equalize for the losses. > >John
From: krw on 10 Apr 2010 18:55 On Thu, 8 Apr 2010 22:31:48 -0500, "Tim Williams" <tmoranwms(a)charter.net> wrote: >>>Delay lines can't store milliseconds of pre-trigger data. The best >>>they do is let you see a few ns of pre-trigger waveform. >> >> Enough to see what caused the trigger (and more than a few nS in some >> cases). > >One case where a DSO comes in handy: >http://myweb.msoe.edu/williamstm/Images/Induction1203.jpg >something was clicking erratically, possibly a gate drive, I'm guessing it >stuck on for at most a few cycles. Bad sign, and the clicking means >magnetics, or worse yet, sheer amperes, are causing audible movement of >wires or capacitors. You can see a number of cycles on this exposure, where >current (bottom, triggered) is going wild, and you can see some voltage >steps where the coupling capacitor got charged by this action. But without >a pretrigger on the order of microseconds, I can't very well see when it's >misbehaving. I don't know who you think said that DSOs have no purpose, or are you into strawmen today?
From: John Larkin on 11 Apr 2010 14:18 On Sun, 11 Apr 2010 10:52:36 -0700, Fred Abse <excretatauris(a)invalid.invalid> wrote: >On Wed, 07 Apr 2010 19:17:44 -0700, JosephKK wrote: > >> The old Tek scopes were DVSTs. Two guns, one write gun and one projector >> gun both on the same side of the storage grating. The original Tek storage scopes didn't have a grating. They used secondary emission off the surface of the phosphor, a trick that had been around for a while [1]. They had a light trace on a paler illuminated bachground, the illumination coming from the flood gun. > >I always preferred the HP storage tubes over the Tek ones. Some of the later Tek scopes used the HP-style mesh storage effect. They looked great compared to the older washed-out secondary-emission things, bright trace on black background, nice variable persistance, good tube life, but the writing rate wasn't as good. I think Tek and HP had a blanket cross-license on oscilloscope technology. The story is in Lee's book on the history of Tek, as I recall. There was an argument over whether some license fee would be donated to the Stanford or Portland football teams. John [1] I think it was Whirlwind that used secondary-emission CRTs as RAM.
From: John Larkin on 11 Apr 2010 14:36
On Sun, 11 Apr 2010 10:52:37 -0700, Fred Abse <excretatauris(a)invalid.invalid> wrote: >On Wed, 07 Apr 2010 15:58:46 +1000, David L. Jones wrote: > >> Iwatsu still do a 1GHz analog storage scope at $28K: >> http://www.tequipment.net/IwatsuTS-81000.html >> >> The 400MHz analog is $7500: >> http://www.tequipment.net/IwatsuSS-7840.html >> and the 470MHz at $12K+: >> http://www.tequipment.net/IwatsuSS-7847A.html >> Ouch! > >They all appear to use scan converter tubes, effectively a small CRT >coupled to a CCD with LCD raster display. > >If they're anything like the 400MHz, LeCroy-badged one that I had on demo >for a few weeks, some years ago, the trace will be unacceptably thick. We >sent that one back. > >I'd happily pay $28K plus for something the ilk of a 7104. 7103s and 7104s appear on ebay for around the cost of shipping. Our 7104 is the only analog scope I ever use. John |