>> It is different for a circuit that isn't a 1 pole RC. > > > no, it's whenever an integrator (1/s in the s universe) is implemented > numerically with the trapezoid rule. doesn't matter whether it's a C or > anything else.
RBJ: please show me the derivation for a 2 pole Sallen Key using the bi-linear transform, then I'll show you the difference between using trapezoidal integration (which preserves each capacitors state directly in from the time domain structure of the circuit) and the bi-linear transform used by engineers (which operates on the s-domain generic 2 pole biquad laplace representation so throws away the original structure and state of the circuit) In the one pole case they come down to the same thing (there is only one capacitor), but the bi-linear transform is actually derived from the time domain trapezoidal rule. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
