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SPICE AC analysis -- multiplying or dividing signals

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...

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...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson
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"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

Reply to
Robert

Robert, I'd like a copy as well. Thanks!

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
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

Reply to
Joel Kolstad

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

Reply to
Joel Kolstad

Somewhere I think I have safely stashed away an even simpler way... stashed so safely I can't find it :-(

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
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

Reply to
Joel Kolstad

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

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
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

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-- fig.

19 on page 11). I'm guessing the various ranges correspond to switching in various fixed capacitors, so presumably the frequency range is ultimately determined by how large a capacitor you're willing to build into your IC?

---Jowl

Reply to
Joel Kolstad

Yep.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
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

Reply to
Robert

Got it! Thanks!

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
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.

--
Mark
Reply to
qrk

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

Reply to
Joel Kolstad

Sure.

PSpice app-note...

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Robert Hickey's method...

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...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
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

[1]
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Reply to
Robert

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