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| Why did Tektronix stop making the great scopes? |
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| T3sl4co1l:
--- Quote from: SeanB on December 24, 2014, 06:27:07 pm ---Making a CRT is easy. But to make a CRT that has 1GHz bandwidth, has less than 1% non linearity over the full brightness range, and which will give a similar brightness irrespective of the beam speed, and where you have amplifiers which have a 1GHz bandwidth and both DC stability and still can drive a 200pF load at 1GHz with 400Vpp and do so linearly is hard. --- End quote --- Nah, they never had it that hard. Even in the toob days (no shortage of deflection voltage there), they moved to distributed deflection -- it's just so much better. And more sensitivity means less voltage, means less power needed and no need for matching between a row of tubes (high impedance outputs) and the transmission line. Practically just drive the thing with a cathode follower, and you're there! Probably the big crusty electrostatic picture tubes needed voltages like that, but scope tubes have always been in the 200Vpp range max. Which is 100Vpp per plate, so you only need a 150-250V supply to do a good job of it. Combined with distributed deflection and the deflection-enhancing shield mesh, I think they got down to something like 20Vpp in the 475, and less in the faster and special purpose units. All made with normal (30-60V?) transistors, hybrids and ASICs. Since scopes long since moved away from high vertical deflection voltages, the only remaining application for high voltages at high bandwidths -- were actually high resolution CRTs, because the video bandwidth is upwards of 100MHz (e.g., >163MHz pixel clock for 1600 x 1200 x 85Hz refresh), and the cathodes must be driven with about 50-100Vpp. Late model CRTs used monolithic chips; possibly some of the best discrete transistors ever made were Sanyo parts, used in the early and mid model Trinitrons (and other high res CRTs), a typical example being 1GHz fT, 100-160Vceo and 200mA Ic (e.g., 2SC3995 I think?). Today, such transistors are all but unheard of. A shame, because they're still handy for niche applications. There are RF parts available for voltages like that, but it's usually because you get more power at higher voltages. There are some industrial 13.56MHz (and such) applications where a bus over 100V is desirable, so there are some parts made for those sorts of applications. There's some interest in SiC and GaN for faster power switching applications as well (pushing 1 or 2 MHz, nothing crazy), but it's still very early. Tim |
| Richard Crowley:
--- Quote from: LabSpokane on December 24, 2014, 04:34:43 pm ---It was notable that in the "Silicon Forest" of Portland and Vancouver during that era, virtually every other tech company was growing while Tek continued to shrink. Before Tek, Portland was basically a big logging/timber town with surrounding agriculture in the Willamette Valley and Vancouver was a shipyard. Tek changed everything there. It's sad to see them essentially gone. --- End quote --- OTOH Intel has effectively replaced Tek as not only the largest employer in the state (with roughly equivalent # of workers), but Oregon is the largest Intel site on the planet. All of the microprocessor processes were developed here, and every Intel CPU since the 386 saw "first silicon" here in our development fabs in Aloha and now in Hillsboro, Oregon. |
| LabSpokane:
--- Quote from: T3sl4co1l on December 25, 2014, 05:46:33 am --- It's funny because whenever I see one of their old scopes advertised as e.g. "portable, technician, maintenance, logging", I think... why would you need a scope with your chainsaw? ;D Tim --- End quote --- Because you bought a fancy, new Husqvarna saw and need to probe the uC. ;) The old Tek had a great corporate culture. I think it was a magical place to work while it lasted. |
| Wuerstchenhund:
--- Quote from: Richard Crowley on December 25, 2014, 06:06:44 am ---Oregon is the largest Intel site on the planet. All of the microprocessor processes were developed here, and every Intel CPU since the 386 saw "first silicon" here in our development fabs in Aloha and now in Hillsboro, Oregon. --- End quote --- I don't think that's true. For example, the original Pentium-M (Banias) saw "first silicon" in intel's Israel R&D fab in Haifa where the processor was also developed. The same is true for the mobile Core 2 (Merom) and Sandy Bridge and Ivy Bridge. What has been developed in Oregon however is the architecture that was about to kill intel in the mobile/desktop/server CPU market for good: Netburst. The Israeli engineers essentially saved intel at that time from the Netburst disaster and laid the foundation for subsequent processor series (Core, Core 2, Core i) which brought intel back to success. The truth is that without the R&D fabs in Israel there's a very good chance that intel would have become irrelevant in the general purpose CPU space. |
| EEVblog:
--- Quote from: Howardlong on December 25, 2014, 01:35:16 am ---That's a pretty fair appraisal IMHO. As an example, given the choice between a 2467B and a basic ten year old TDS 2024B 2Gs/s 200MHz real time DSO I'd choose the TDS 2024B. Having single shot storage even with the crappy 2.5k memory that the TDS 2024B offers is probably the single most valuable feature, overriding the superior bandwidth capabilites of the 2467B. --- End quote --- I'd go further than that and say I'd rather have a TDS220 than a 2465/7 if that's the only scope I could have for day to day use. That's saying something, because I love analog scopes. |
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