Turn your Rigol DS1052E Oscilloscope into a 100MHz DS1102E
in [Design]
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From: Phil Hobbs on 5 Apr 2010 19:42 On 4/5/2010 2:54 PM, John Larkin wrote: > On Mon, 05 Apr 2010 14:30:50 -0400, Phil Hobbs > <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> On 4/5/2010 2:23 PM, John Larkin wrote: >>> On Mon, 5 Apr 2010 11:17:56 -0700, "Joel Koltner" >>> <zapwireDASHgroups(a)yahoo.com> wrote: >>> >>>> "John Larkin"<jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>>> news:q90kr5pda1mtti9pea5c7tqmao0u9qvfpi(a)4ax.com... >>>>> Rigol is like >>>>> someone who used to leave their front door unlocked, until someone >>>>> wandered in and stole something, so now they have to lock it. >>>> >>>> I think it's more like Rigol sells houses, and you bought a two-bedroom house >>>> (although you're aware they also sell three-bedroom houses)... and one day you >>>> notice (or Dave Jones metnions that) there's another door in your home. >>>> There's no lock on that door, no sign on it saying, "keep out!," etc. Your >>>> ne'er-do-well liberal democrat son moves back home after flunking out of his >>>> liberal studies program at the local college and you get to thinking... having >>>> that kid spend his nights in his own room rather than sleeping on the couch in >>>> the living room every night would be nice... I wonder what's behind that door? >>>> >>>> :-) >>> >>> Not entirely the same. It costs money to build rooms, but it costs >>> nothing to enable IP. Both have market value. >>> >>> But why didn't they do the 50 and even 20 MHz bandwidth limits >>> digitally? They have 1G samples/second to work with. There are some >>> saturation issues that might be best handled with analog limiting, but >>> this *is* a cheap scope. >>> >>> John >>> >> >> One possible reason is that with an analogue bandwidth limit, signals >> that would be aliased get attenuated before sampling. >> > > But it's a 1 GHz sample rate. If it's analog limited to 100 MHz, they > can do most anything with it. Decimating won't create aliases, will > it? > > John > No, but if you have really wideband stuff it'll get aliased down into the fundamental interval. I could probably be argued round, but for my money, analog bandwidth limiting is the ticket. Of course I usually do it with a filter hacked together in a blue Pomona box hung on the input BNC. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: George Jefferson on 5 Apr 2010 19:50 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:deakr5h76s5efoquco0lemv840qg4154od(a)4ax.com... > On Mon, 5 Apr 2010 11:17:56 -0700, "Joel Koltner" > <zapwireDASHgroups(a)yahoo.com> wrote: > >>"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>message >>news:q90kr5pda1mtti9pea5c7tqmao0u9qvfpi(a)4ax.com... >>> Rigol is like >>> someone who used to leave their front door unlocked, until someone >>> wandered in and stole something, so now they have to lock it. >> >>I think it's more like Rigol sells houses, and you bought a two-bedroom >>house >>(although you're aware they also sell three-bedroom houses)... and one day >>you >>notice (or Dave Jones metnions that) there's another door in your home. >>There's no lock on that door, no sign on it saying, "keep out!," etc. >>Your >>ne'er-do-well liberal democrat son moves back home after flunking out of >>his >>liberal studies program at the local college and you get to thinking... >>having >>that kid spend his nights in his own room rather than sleeping on the >>couch in >>the living room every night would be nice... I wonder what's behind that >>door? >> >>:-) > > Not entirely the same. It costs money to build rooms, but it costs > nothing to enable IP. Both have market value. And you believe that ripping people off is IP and has market value. That is the difference between you and me.
From: John Larkin on 5 Apr 2010 19:51 On Sun, 4 Apr 2010 13:10:09 +0800, "Andrew" <anbyvbel(a)yahoo.com> wrote: >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:1pg9r5tes24ml91m59jag6jna6rctpmvg0(a)4ax.com... > >>>Except with software you agree to a EULA prohibiting you from doing that >>>yourself. No such agreement exists when purchasing a scope from eBay, >>>hence >>>it is "not illegal" to do so unless you were intending to defraud (you >>>were >>>the one who suggested not being illegal trumps the moral argument over >>>over-clocking ADCs). >>> >>>Mark. >>> >> >> Lawyers certainly do attack software users for misuse of their >> products, wherever they purchased them. Autodesk did it to us; >> fortunately we had done nothing wrong and their lawyer was stupid to >> boot. When instruments become software-driven, they may well be >> subject to the legal provisions that protect software. > >Only if you signed an agreemnt to that effect during purchase. I signed no agreements with Autodesk. Because they copyrighted their software, they exercize control over it whether I agree or not. Bith copyrights and patents give the owner rights over their IP. John
From: George Jefferson on 5 Apr 2010 19:53 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:q90kr5pda1mtti9pea5c7tqmao0u9qvfpi(a)4ax.com... > On Mon, 5 Apr 2010 14:42:48 +1000, "David L. Jones" > <altzone(a)gmail.com> wrote: > >>John Larkin wrote: >>> On Fri, 2 Apr 2010 20:23:54 +1100, "David L. Jones" >>> <altzone(a)gmail.com> wrote: >>> >>>> For those who thought Rigol may bin the scopes to get 50MHz and >>>> 100MHz models, and that they aren't actually identical hardware and >>>> firmware, I've been informed that Rigol have finally admitted this >>>> to an irate customer who contacted them about the issue. >>>> >>>> Partial Quote from Rigol : >>>> "The firmware of the instruments is made >>>> to enable capability based on the version purchased just like any >>>> software licensed product you would buy." >>>> >>>> Betcha they would never have admitted that before it was all exposed >>>> a few weeks ago. >>>> >>>> Dave. >>> >>> Too bad that, with all this ranting, this thread is missing a couple >>> of interesting technical issues re: the varicap bandwidth limiter and >>> the compromises it forces. >> >>I find that funny considering it was you who started the ranting and also >>continued it ad nauseam. > > Not so. I pointed out a possible legal issue, and brought the > interesting but unresolved issue of how one amortizes and prices > things, like firmware, that have no incremental cost to manufacture. > Most perple here seem to feel that it's a ripoff to charge for such > things, and a minority feel, as I do, that Rigol did nothing wrong and > provides very good price:performance for both models. Rigol is like > someone who used to leave their front door unlocked, until someone > wandered in and stole something, so now they have to lock it. They did nothing wrong. They had identical products(or all intents and purposes) but slapped two different labels on them and charged different prices for generating revenue. DIFFERENCE BETWEEN US? You think that's ethical. http://en.wikipedia.org/wiki/False_advertising I bet you have no problem with any of those methods to rip off the customer. Either you are terribly naive or just as bad as rigor. See that your going far out of your way to find justifications doesn't say much about your na�vet�.
From: John Larkin on 5 Apr 2010 20:01
On Mon, 05 Apr 2010 21:08:34 GMT, nico(a)puntnl.niks (Nico Coesel) wrote: >John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Mon, 05 Apr 2010 14:30:50 -0400, Phil Hobbs >><pcdhSpamMeSenseless(a)electrooptical.net> wrote: >> >>>On 4/5/2010 2:23 PM, John Larkin wrote: >>>> On Mon, 5 Apr 2010 11:17:56 -0700, "Joel Koltner" >>>> <zapwireDASHgroups(a)yahoo.com> wrote: >>>> >>>>> "John Larkin"<jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>>>> news:q90kr5pda1mtti9pea5c7tqmao0u9qvfpi(a)4ax.com... >>>>>> Rigol is like >>>>>> someone who used to leave their front door unlocked, until someone >>>>>> wandered in and stole something, so now they have to lock it. >>>>> >>>>> I think it's more like Rigol sells houses, and you bought a two-bedroom house >>>>> (although you're aware they also sell three-bedroom houses)... and one day you >>>>> notice (or Dave Jones metnions that) there's another door in your home. >>>>> There's no lock on that door, no sign on it saying, "keep out!," etc. Your >>>>> ne'er-do-well liberal democrat son moves back home after flunking out of his >>>>> liberal studies program at the local college and you get to thinking... having >>>>> that kid spend his nights in his own room rather than sleeping on the couch in >>>>> the living room every night would be nice... I wonder what's behind that door? >>>>> >>>>> :-) >>>> >>>> Not entirely the same. It costs money to build rooms, but it costs >>>> nothing to enable IP. Both have market value. >>>> >>>> But why didn't they do the 50 and even 20 MHz bandwidth limits >>>> digitally? They have 1G samples/second to work with. There are some >>>> saturation issues that might be best handled with analog limiting, but >>>> this *is* a cheap scope. >>>> >>>> John >>>> >>> >>>One possible reason is that with an analogue bandwidth limit, signals >>>that would be aliased get attenuated before sampling. >>> >> >>But it's a 1 GHz sample rate. If it's analog limited to 100 MHz, they >>can do most anything with it. Decimating won't create aliases, will >>it? > >That depends on the steepness of the input filtering. It will need to >roll-off more than 48dB not to have any aliasing products at fs/2. I >doubt they decimate. 2GB/s is a lot to handle by the low cost FPGA >they use (Altera Cyclone IIRC). I strongly doubt digital realtime >filtering is feasible. Whatever aliases the 100 MHz version has, the 50 MHz mode won't be much better. My 1052 amazed me by having user-programmable lowpass/highpass/bandpass filtering. If the FPGA can move 1 Gs/s data, it shouldn't be hard to implement a simple FIR filter to knock 100 MHz response down to 50. The filter wouldn't be realtime in the sense that only display data needs to be filtered, and I suspect displays aren't updated all that often. They already seem to have the digital filtering they need. John |