Very fast oscilloscopes
in [Design]
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From: Joerg on 30 Apr 2010 12:29 Joel Koltner wrote: > "Kevin McMurtrie" <mcmurtrie(a)pixelmemory.us> wrote in message > news:4bda772b$0$22160$742ec2ed(a)news.sonic.net... >> It's a little scary that such an expensive piece of precision hardware >> runs Windows. Whatever happened to using simple embedded operating >> systems that don't have a zillion extra features to crash? > > The idea is that Windows programmers are a dime a dozen, Windows itself > is "cheap enough" (~$25-$100, depending on the version of Windows and > the quantity, is nothing in an instrument with a five- or six-digit > price tag!), and hence it's faster and cheaper to just use something > "off the shelf" rather than rolling your own OS. > > Heck, some software guys I know are currently lobbying to buy not just > an OS, but an RTOS to run something on the order of complexity of a > cordless DECT phone (i.e., LCD display, handful of buttons, two-way > low-speed digital wireless, etc.); they've budgeted $50k for it. I'm > not personally very enthusiastic about this, but I'd have to admit that > if it saves them from having to hire one person even for six months to a > year to write additional software, it will have paid for itself. > You have to add the runtime license fees per unit into the equation. That cost is usually perpetual. The other cost in a portable application is the consequential energy overhead. Larger and more expensive battery, larger enclosure (which end users might not appreciate that much). > What I worry about is programmers who think that spending money can > somehow magically fix all their bugs, when in actuality the bugs are > largely due to the individual programmers and have very little to do > with the tools they use... and getting more powerful tools can actually > backfire, just giving them more ways to shoot themselves in the foot... > or to blow off their entire leg rather that just a toe. :-) > Key with any realtime OS is to select the right one. I had quite a positive impression with QNX, also WRT its footprint. But with phone type apps there may be better ones, where there's more pre-cooked modules tailored to that market. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 30 Apr 2010 12:42 Joel Koltner wrote: > "Jeroen Belleman" <jeroen(a)nospam.please> wrote in message > news:hreqff$t7e$1(a)speranza.aioe.org... >> You shouldn't need to. MATLAB, or whatever else you'd like to >> let loose on your acquisitions, can run on the desktop PC, which >> need not run Windows either, incidentally. > > That Agilent scope appears to have the ability to let you write some > Matlab scripts to perform, e.g., custom measurements and run them in > "real time" as the scope is acquiring data, though -- that's pretty > powerful, if you have an actual application for it. (Consider how > annoying it would be if scopes didn't have built-in functions to measure > rise times, frequencies, etc. and you had to transfer the data to your > PC to do it... OK, I realize we all know how to count graticule lines > and calculate this manually, but I think you get the point... even 25+ > years ago when analog scopes were king many of the classics like the Tek > 2465B were already digitally measuring these parameters for you...) > I have yet to explore all the fancy trigger or math stuff in my DSO but it's amazing how fast a waveform shows up on the PC via streaming USB. Besides the normal screen shot view it also transfers Excel-ready data if that option is checked. I have not done it yet but I assume from there you are only a few VBA routines away from performing really fancy routines with the data. Excel can stomach running displays, I did that with a LabJack once. The transfer is so fast that I sometimes use the laptop screen as the main display for this scope, especially when soldering fine-pitch SMT. That way I don't have to switch glasses but can just peek over the top of the 3x magnifiers. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: John Larkin on 30 Apr 2010 12:55 On Thu, 29 Apr 2010 09:52:59 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >I bet Agilent wants a pretty penny for their new 32GHz real-time scopes: >http://cp.literature.agilent.com/litweb/pdf/5990-5271EN.pdf > >And to think that it was only ~20 years ago that a Tek 11802 with the SD-24 >(24GHz) sampling head -- that samples at all of 100kHz -- was the hotest >ticket... now available on eBay for some single-digit percentage of the >original price... > >---Joel I recently got this email from my friend Mark Kahrs, the sampling-scope-history expert: ========================== Yes, the former Soviets did have a 7 GHz real time scope, and a 20 GHz transient digitizer. They both used the same technique to get the super high speed � keep the deflection angle low. When I managed a design project in the transient digitizer group at Tek, I went on a customer visit and met with engineers working for EG&G at the Nevada Test Site. The time was after Glasnost, near the end of the era of underground testing. A delegation of Soviet scientists were actually invited over to witness a test shot (They did the same, hosting a group of scientists from Livermore National Labs). EG&G was using the new 3 GHz transient digitizer from Tek, and thought its "leading edge" technology would impress their former foes. The Soviets were not impressed, stating that they had a 20 GHz digitizer. How did they do it? They way they surpassed many obstacles � by not placing needless restrictions on the technology. A design requirement for the US made digitizers was that they must fit in a standard 19" rack. The Soviets took a pragmatic approach, and avoded any size restrictions. The CRT in their digitizer was just short of 10 m in length! They used traveling wave distributed deflections plates as our designs did, but the beam deflection angle was incredibly small, allowing very high BW. Likewise, the 7 GHz real time scope had a CRT over 3 meters long. The funny part of this true story is that the EG&G team, confident that they had just showed what they thought was superior technology, asked if the Soviet scientists had any questions about it. They did. They asked "How do you get the walls so smooth in the tunnels?" The shot monitoring tunnels at NTS were drilled with diamond tipped tunnel boring machines, leaving a relatively smooth wall. The Soviets simply blasted their tunnels with dynamite. ================= John
From: Joel Koltner on 30 Apr 2010 13:32 Great story John -- thanks for posting that!
From: Joerg on 30 Apr 2010 13:41
John Larkin wrote: [very interesting story] > The funny part of this true story is that the EG&G team, confident > that they had just showed what they thought was superior technology, > asked if the Soviet scientists had any questions about it. They did. > They asked "How do you get the walls so smooth in the tunnels?" The > shot monitoring tunnels at NTS were drilled with diamond tipped tunnel > boring machines, leaving a relatively smooth wall. The Soviets simply > blasted their tunnels with dynamite. > It is rumored that the end of the Krasnojarsk over-the-horizon radar didn't come because of glasnost developments but more because of crumbling masonry and concrete. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |