Talk:Bode plot

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[edit] Straight lines

"It is especially useful in this case because the complex curves that appear in a linear magnitude-frequency plot can often be approximated by straight lines in a Bode plot."

Can't it always be approximated by straight lines? Isn't that how a Bode plot is drawn? It's just that the approximations are not so accurate for certain systems? Specifically, what are the straight line asymptotes for a Chebyshev filter? - Omegatron 16:36, May 17, 2005 (UTC)
I suppose the question is how accurately can it be approximated by straight lines (and how many straight lines you are going to use). RJFJR 16:43, 6 October 2005 (UTC)

[edit] lowpass filter needs image

The comment about RC lowpass filter should ahve an image, but that is a particularly simple case so we probably want a more complicated one too. (Preference to bode-phase plot, I'd say). RJFJR 16:43, 6 October 2005 (UTC)

Image added. :-) — Omegatron 19:51, 8 October 2005 (UTC)

[edit] simples rules?

The article says: "These asymptotic approximations are useful because they can be drawn by hand following a few simple rules.",

but it doesn't say what they are. I think its talking about the rules:

For a transfer function in the form H(s) = A \prod \frac{(N_n)^{a_n}}{(D_n)^{b_n}}
where s = jω, N is a numerator term, D is a denominator term, and H is the transfer function.
  • start with a straight line at H(0)
  • at every value of s where N = 0 (a zero), increase the slope of the line by 20*an dB per decade.
  • at every value of s where D = 0 (a pole), decrease the slope of the line by 20*bn dB per decade.

For some reason s is equivalent to -ω when graphing. My explanation here isn't very well written, and probably has incorrect explanation. It would be very nice if someone could add this sort of thing onto the page. Fresheneesz 22:16, 4 May 2006 (UTC)

It's covered in the external links, too. I was going to add it to the article, but haven't gotten around to it. You know how it is... — Omegatron 23:12, 4 May 2006 (UTC)
Heh, yea, I'm only learning about them, so anything I might add is subject to stupidity. But maybe I'll hazard it anyway. Fresheneesz 01:57, 5 May 2006 (UTC)

[edit] complex poles and zeros

Needs something on complex poles and zeros - I'm not up for it. Fresheneesz 09:37, 14 May 2006 (UTC)

[edit] Merge

I have suggest that Bode plotter be Merged to Bode plot. 24.126.199.129 21:51, 22 August 2006 (UTC)

[edit] NonMinimum Phase?

whadaya think about adding stuff about TFs w/ -s+xn in the numerator or den. or other combinations of that sort? —The preceding unsigned comment was added by 128.46.105.66 (talk) 17:05, 8 December 2006 (UTC).

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