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I've been looking for some straightforward method or trick to obtain the transfer functions of active filters (like the Sallen-Key filter, the butterworth or Cauer topology etc...) since KCL or KVL requires a lot of algebraic manipulations. I've heard that SFG (signal flow graphs) could be very helpful, but with my minimum of experience I can not found any worth reference that treat the subject, so what I am looking for is some brief explanation of SFG with introductory applications to the basic models and topologies of active filters and thanks.

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Is as better home for this question? – Qmechanic Mar 26 '13 at 19:49
I have done it before , but it seems that the subject is already dead . – Ibrahim Mar 26 '13 at 19:58
Cross-posted from – Qmechanic Mar 26 '13 at 20:06

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