Agreed. I DID previously post....
I haven't tried it, but the multiplication may require _multiple_ steps to accomplish:
(1) Separate out the real and imaginary parts (2) Do the appropriate multiplications (3) Sum appropriate parts to get the resultant real and imaginary terms
[snip]Also...
...Jim Thompson
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com... [snip]
I have an old App Note from Wes Hayward showing a method to do that in PSpice which we used at TriQuint. IIRC, it's a Word Document but small enough to email if you're interested Joel.
Robert
Robert, I'd like a copy as well. Thanks!
...Jim Thompson
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Thanks for the link... for measuring S11 and S21, that's very similar to what I use, although I split apart the voltage sources (making one dependent on the other, rather than putting them "in-line" as shown); I also made the source voltage and source and termination resistances parameters. I hadn't yet tackled trying to get tables of S parameters *into* SPICE; I do like the way they do it.
---Joel
Hi Mike,
SIMetrix doesn't have a .net statement, and I'm thinking PSpice doesn't either, although I certainly could be mistaken there.
But you say that LTspice does, eh? Sheesh... your piece of freeware there looks better and better every day!
Thanks,
---Joel
Somewhere I think I have safely stashed away an even simpler way... stashed so safely I can't find it :-(
...Jim Thompson
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
I started looking at what it would take to do it in SIMetrix, and unfortunately SIMetrix doesn't have something as nice as a voltage source with a table-defined output vs. frequency (as that app note uses in PSpice). They
*do* have functions to lookup (and even interpolate) data stored in an X-Y array (e.g., voltage magnitude or phase vs. frequency, taken from S parameter data), and they give you access to the parameter HERTZ (the current simulation frequency during AC analysis), so I believe there's enough functionality there to create a table-based voltage source... I'll just have to work on that *first*.Hmm... too bad John Warner (Mr. SIMetrix) doesn't seem to hang out in these forums anymore.
Fun with SPICE here is about to get put on hold since I need to get an RF front-end working before leaving the country in another week and a half. It'd be nice if you IC designer guys would make a VCO-based synthesizer with a, say, 30% bandwidth (e.g., 1-1.3GHz)... so far I haven't seen anything over
20%, and many are only 10%; I could save a few ICs.---Joel
The way we do it on custom ASIC's is with range-switching.
Most of my stuff is usually single, or just two specific frequencies.
...Jim Thompson
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Apparently there's already some of that within many ICs, e.g., Analog Devices' ADF4360
---Jowl
Yep.
...Jim Thompson
Done. Let me know if it got there.
As I mentioned, Wes Hayward wrote the original App Note. I believe he created the technique independently quite a while ago. But from what you've said it may be the same way as you've mentioned.
Robert
Got it! Thanks!
...Jim Thompson
I recall some flavors of Spice having the B source (non-linear dependent source)? I know you can put expressions in a B source, but don't know if you can use tables. Or, make an equation from your table data.
Jim,
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Could you drop a copy on ABSE or your web site, perhaps? :-)
Thanks,
---Joel
Sure.
PSpice app-note...
Robert Hickey's method...
...Jim Thompson
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Please! I don't like credit for someone else's work. Wes Hayward [1] did the original App Note. And I believe he created the technique way back when. I just rewrote it as part of my job at the time.
Robert
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