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# Tips & Tricks: Avoid Harmonic-Balance and SPICE software flaws for time-domain simulation

8/9/2012 05:24 PM EDT
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re: Tips & Tricks: Avoid Harmonic-Balance and SPICE software flaws for time-domain simulation
8/10/2012 3:41:05 PM
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re: Tips & Tricks: Avoid Harmonic-Balance and SPICE software flaws for time-domain simulation
8/10/2012 5:50:24 PM
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Reply to RF Austin's comment: Design article information: See the quotation of text from Session WSO at 2008 IEEE International Microwave Symposium, that explains the problems with the present software; see references [1], [2] and [3]that tell in detail how to avoid the problems of the present popular software. All of that tells how to design so that the present software problems will be avoided. If you want, you can reach me at E-mail nathansokal@gmail.com

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re: Tips & Tricks: Avoid Harmonic-Balance and SPICE software flaws for time-domain simulation
8/16/2012 3:48:20 PM
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The key to this article is the title word "linear". In the "real" world, switches are rarely linear. SPICE was designed, specifically, to incorporate nonlinear component behaviors. If you think that a linear-component-based analysis is sufficient, then you've probably never designed a real switching circuit. If you are satisfied with the assumption of linearity, however, then you might consider this article to be useful. But most switchmode designers understand that nonlinearities are a significant issue in switchmode designs. Furthermore, SPICE component models are available for many, many devices, whereas, you will need develop your own linear "model" for use in the linearized technique described. SPICE is provably capable of very accurate analysis of nonlinear switched circuits, both in detailed transient and state-averaged model modes. While I haven't read the article in question in detail, the use of linear switch assumptions and a "linear algebra" based analysis are a clear indication that component nonlinearities are ignored. As an example of the more realistic capabilities of SPICE modeling, I suggest readers check out my website discussing SPICE-based averaged switchmode models at https://sites.google.com/site/rstevescott/home/Averaged-PWM-Models SPICE can incorporate nonlinear component characteristics to an extent that NO linear-algebra-based analysis can. Why lower your standards and simulation expectations?

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re: Tips & Tricks: Avoid Harmonic-Balance and SPICE software flaws for time-domain simulation
8/17/2012 7:22:09 PM
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Robert Steven Scott: You said "while I haven't read the article in question in detail ...". You and I are solving different problems. What you are solving looks fine, but what I'm solving is different: only switching-mode power amplifiers. Nathan Sokal You can reach me at nathansokal@gmail.com .

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re: Tips & Tricks: Avoid Harmonic-Balance and SPICE software flaws for time-domain simulation
8/22/2012 11:39:25 PM
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Mr. Sokal, Thank you for your response. You are entirely correct, I have no knowledge of switchmode RF amplifiers. My response was based entirely on my experience with switchmode power converters. I intend to consider your article further and, hopefully, with more consideration towards the specific application of RF amplifiers. Thank you for your article. Best regards, R. Steve Scott