From: boris petkovic
Date: Sat, 3 Mar 2001 04:33:52 -0800 (PST)
Subject: Re: [TSSP] Reactive part of base input impedance
Hi All, > So perhaps the "true" F1 is better defined as the > point were Vin x Iin > reaches a maximum or the input Z is least? ---- Well,you can define it as concerns secondary distributed structure in various ways. In a lumped RLC circuit and CW excitation case, that is very easy to destinguish-Two possibilities: 1) Frequency where the voltage on a reactive component reaches maximum. 2)Frequency where Zin reaches minimum. For high Q circuit these two freqs. differs very little one from another. Simple algebra expressions showing that can be derived. For high Q TC secondary structure ,CW excited,situation is much more complicated. Yes,again, F1 frequenciy where Zin reaches minimum and the frerquency where top voltage reaches maximum are close but my gut feel tells me they don't differ in the same way like 1) and 2). I tried in past to find some simple correlation in that direction for distributed resonator,and was unable to. Besides,TSSP simulator would be much better tool for exploring it than the methods I used then. --- > > I just realized I shouldn't have been looking at top > voltage in the scope > picture... but rather input voltage... Since the > two frequencies, in any > case, are very close, this is more of a theoretical > concern. I wonder if > the "true" f1 is (Fv + Fi)/2 or SQRT(Fv^2 + Fi^2)?? ---- Isuppose the last one should be SQRT((Fv^2 + Fi^2)/2)? Also why not 2/(1/Fi + 1/Fv) or SQRT(Fi*Fv) ... ? Few months ago, I asked Paul what he considered by resonant frequency of secondary (thread "early idle testing" as far as I remember). The Frequency where top voltage reaches maximum he said. TSSP simulator is set to find resonant frequency following such pattern I guess,so conventionally, we should agree that one to call "true" f1. > > But perhaps the top voltage maxima and the input > power maxima are exactly > the same frequency... ---- I affraid they are not.(It would be nice if that's true.Just imagine a simplification of msms). Regards, Boris __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.