**From:** Ray Anderson (*raymonda@ha1mpk-mail.eng.sun.com*)

**Date:** Mon Aug 07 2000 - 11:17:45 PDT

**Next message:**Andrew W. Riley III: "Re: [SI-LIST] : best layer stackup for 2 PWR 4 Signal and 100 Oh"**Previous message:**Farrokh Mottahedin: "[SI-LIST] : Undoped or Non-doped Isolation Transistor"**Maybe in reply to:**Sean Murray: "[SI-LIST] : Bandwidth/Frequency Response simulations"**Next in thread:**Lynne Green: "RE: [SI-LIST] : Bandwidth/Frequency Response simulations"**Reply:**Lynne Green: "RE: [SI-LIST] : Bandwidth/Frequency Response simulations"

Sean-

Bandwidth/Frequency Response simulations are frequency domain simulations.

Typically done using spice or some other simulator that supports

frequency domain simulation (HP ADS, Touchstone, Compact, Vipec, etc.).

A network analyzer (either scalar or vector) makes these measurements

in the lab.

This sort of simulation can be used to determine the losses of a t-line

over a wide frequency range, the response of narrow band structures

(filters etc.), simulating the impedance profile of a power distribution

plane, and probably a multitude of other applications.

Just about any measurement that you might make in the time domain using

an oscilloscope or TDR has an analogous counterpart in the frequency domain.

Some phenomena are easier to visualize in the time domain while others are best

observed in the frequency domain. The fft and ifft allows you to transform between

them if you have measured or simulated data. Be careful though, as the Fourier

transform can easily lead you astray if it isn't applied properly. The rounding

on the edges of a fast rise-time signal that you might observe on a scope

are the result of the higher frequency components being attenuated. A transmission

line that causes such rounding of the edges would show more losses at high

frequencies when a frequency domain simulation or measurement is made.

As far as using Pads data as input to a freq. domain simulator, I'm not aware

of any, but then again I never had the need to look for one either.

-Ray

*>
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*> Anyone know what this is and how and what you use to do this sort of
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*> simulation? I have asked hyperlynx and did not have any luck. Are there
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*> companies that can take Pads data and simulate your designs for you?
*

*>
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*> Regards,
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*> Sean Murray
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*> General Manager
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*>
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*> M&M Specialties Inc.
*

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**Next message:**Andrew W. Riley III: "Re: [SI-LIST] : best layer stackup for 2 PWR 4 Signal and 100 Oh"**Previous message:**Farrokh Mottahedin: "[SI-LIST] : Undoped or Non-doped Isolation Transistor"**Maybe in reply to:**Sean Murray: "[SI-LIST] : Bandwidth/Frequency Response simulations"**Next in thread:**Lynne Green: "RE: [SI-LIST] : Bandwidth/Frequency Response simulations"**Reply:**Lynne Green: "RE: [SI-LIST] : Bandwidth/Frequency Response simulations"

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