How can I build a simple pulse generator to demonstrate transmission lines
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How can I build a simple pulse generator to demonstrate transmission lines
1–10 of 21 posts
Re: How can I build a simple pulse generator to demonstrate transmission lines
#2Nice write up and sneaky introduction to time-domain reflectrometry but I'd like to point out the classic answer to this question is the famous Jim Williams pulse generator: https://github.com/podonoghue/Jim_Williams_Pulse_Generator?t...
Re: How can I build a simple pulse generator to demonstrate transmission lines
#3Decades ago we used a much simpler method. A few 50 or 75 ohm non-inductive resistors and a tunnel diode.
Feed any (slow) pulse generator into the diode and make it switch. Tunnel diodes can have sub-nanosecond switching times.
We also used this technique to check/measure the rise times of our oscilloscopes.
Re: How can I build a simple pulse generator to demonstrate transmission lines
#4Decades ago we used a much simpler method. A few 50 or 75 ohm non-inductive resistors and a tunnel diode. Feed any (slow) pulse generator into the diode and make it switch. Tunnel diodes can have sub-nanosecond switching times. We also used this technique to check/measure the rise times of our oscilloscopes.
sometimes, I realize how much is taken for granted these days that when I stop to think about is one of those "whoa" (in a Neo voice) moment. being able to time something in the picosecond range just gives me a wry smile.
Re: How can I build a simple pulse generator to demonstrate transmission lines
#5That's pretty cool :)
Re: How can I build a simple pulse generator to demonstrate transmission lines
#6Great article!
aside: I've never seen Stack Exchange used as a blogpost medium (which normally this kind of write-up would be) and I like it! It's still formatted as Q&A so people with the same question can find it, and what's more, suggest edits or write alternative solutions (as OP explicitly invites here) on equal footing themselves. A collaborative quest for the answer, but not anonymized like a wiki.
Re: How can I build a simple pulse generator to demonstrate transmission lines
#7The real gem is the answer at the bottom about doing the same thing with a bit of transmission line you treat as a capacitor.
Re: How can I build a simple pulse generator to demonstrate transmission lines
#8This is a great post about the basics of what happens in transmission lines.
If you need really fast rise times, there are cheap pulse generators that are a couple orders of magnitude faster: https://leobodnar.com/shop/index.php?main_page=product_info&... At this level everything has to be optimized including physical geometry.
Re: How can I build a simple pulse generator to demonstrate transmission lines
#9This is a great post about the basics of what happens in transmission lines. If you need really fast rise times, there are cheap pulse generators that are a couple orders of magnitude faster: https://leobodnar.com/shop/index.php?main_page=product_info&... At this level everything has to be optimized including physical geometry.
I am using Leo Bodnar’s fast pulse generator (SMA) in my lectures to teach transmission lines. With sufficient length (I use ~1m) it works quite well to demo with a low cost scope. I originally bought it for TDR with 40GSPS/15GHz scope, which works very well with few orders of magnitude smaller lengths. Old on has upper length limit with 10MHz fixed frequency. There is a new one available with external sync and variable frequency, but I have not bought/tested it.
Re: How can I build a simple pulse generator to demonstrate transmission lines
#10Any recommended resources for learning the first principles required to understand this and all the components involved?