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Re: Impedance matching question
Through the tube era and the discrete solid state era professional balanced audio lines in radio and recording studios were also impedance matched at 600 ohms (earlier 500 ohms) because they were
By Dale H. Cook · #155591 ·
Re: 11801 is reassembled, up and running :-)
The user manual I quoted has a revision date of May 1989. The August 1988 service manual states the calibrator is < 35 ps. The February 1989 revision page states the same rise time. As I noted
By Reginald Beardsley · #155590 ·
Re: Impedance matching question
Thanks Craig... so, if I were to summarize what you wrote, at such short distances, there's really no opportunity for a reflected signal to go out of phase with the incident signal? In watching the
By David Berlind · #155589 ·
Re: 11801 is reassembled, up and running :-)
They must have changed the cal output circuitry on the later models.
By Bob Koller <testtech@...> · #155588 ·
Re: Impedance matching question
It is to do with the frequency range. As soon as the length of
By Craig Sawyers <c.sawyers@...> · #155587 ·
Re: 11801 is reassembled, up and running :-)
Attachments are not allowed here Reg. Via the website you can create a new Album in the Photos section and put your picture(s) there. If you do so, it's handy for "us" if you insert a link to the
By Albert Otten · #155586 ·
Re: Impedance matching question
That was a decent video, thank you. It doesn't seem like he had problems with the terminators themselves. In fact, he uses them to address mismatches. I'd be curious to know (from anyone who knows)
By David Berlind · #155585 ·
Re: 11801 is reassembled, up and running :-)
Thanks. It will be a while before I take it apart again, but I'll make a note in my service manual. Fortunately, most of my HP gear lists the parts in the manuals, so those will be easier to
By Reginald Beardsley · #155584 ·
Re: 11801 is reassembled, up and running :-)
I may have to take part of that back. In my F/W EPROM collection I don't have 11801 but there is a note saying that 11801 can also use 11801A F/W which I have and it uses both types. I now begin to
By zenith5106 · #155583 ·
Re: 11801 is reassembled, up and running :-)
27C010 and 27C512 /H?kan
By zenith5106 · #155582 ·
Re: Repairability of SD-24, SD-30 & SD-32 sampling heads
Far as I know he still works at a university in Portugal -he's been there for some years and is well known in scientific and amateur (especially EME) circles. 73 Dave, ZL3FJ
By Dave Brown · #155581 ·
Re: 11801 is reassembled, up and running :-)
11801 User manual p 42. "The signal from the calibrator output us a 250 mV square wave with a rise time of approximately 20 ps and a period of approximately 10 microseconds." After I did the
By Reginald Beardsley · #155580 ·
Re: Impedance matching question
Hi: If you haven't watched EEVblog #652, he demonstrates a couple of problems that can arise when using coax, terminators, and Ts, to connect a sig gen to a scope. Cheers.
By Roy Thistle · #155579 ·
Re: 11801 is reassembled, up and running :-)
Great! Calibrator risetime? Isn't the cal output specified at about 250ps? Both of my instrument measure it about 300ps.
By Bob Koller <testtech@...> · #155578 ·
Re: Repairability of SD-24, SD-30 & SD-32 sampling heads
He clearly knows what he is doing. You don't knock up something with an Altera FPGA unless you have a major development lab at your disposal https://www.qsl.net/ct1dmk/gw_04.jpg Craig
By Craig Sawyers <c.sawyers@...> · #155577 ·
Re: Repairability of SD-24, SD-30 & SD-32 sampling heads
Yes, Luis has done great work! He is in South America I think. Ascertaining and sourcing the correct parts can be difficult.
By Bob Koller <testtech@...> · #155576 ·
Re: Impedance matching question
Usually the terminator contains the ground connection.? Going for your description rather than a drawing or photo.?Jim FSent from my Verizon, Samsung Galaxy smartphone
By Jim Ford · #155575 ·
Re: Impedance matching question
A through teminator will give better performance at high frequencies. You can get away with a Tee and terminator up to a few MHz, but things go downhill very quickly after that. A thru terminator
By Reginald Beardsley · #155574 ·
Impedance matching question
I was watching a video on impedance matching experiments and, supposing you had a 75 ohm signal generator connected to a 1 M-ohm oscilloscope input, one option that was suggested was to add a 75 ohm
By David Berlind · #155573 ·
Re: Repairability of SD-24, SD-30 & SD-32 sampling heads
https://www.qsl.net/ct1dmk/wbond_ex.html This guy seem to have made a home hybrid lab and repairs. Could former professionals comment ? Best Jose [email protected]> wrote:
By Jose Luu · #155572 ·