Hello Robert, I did a similar analysis months ago on the SVF topology Andrew posted at that time. The implicit (and most logical) convention is to consider the OTAs as output current generator (as they should, so that a current flows into the cap), the unity/k/mo0/m1/m2 gains as having infinite input impedance and zero output impedance, the summing nodes as having infinite input impedence on each addend input and zero output on the summed voltage node. By doing this the analog counterpart of Andrews scheme works.
Ciao Marco > -----Messaggio originale----- > Da: music-dsp-boun...@music.columbia.edu [mailto:music-dsp- > boun...@music.columbia.edu] Per conto di robert bristow-johnson > Inviato: domenica 21 dicembre 2014 20:25 > A: music-dsp@music.columbia.edu > Oggetto: Re: [music-dsp] Sallen Key with sin only coefficient computation > > On 12/21/14 1:01 PM, Andrew Simper wrote: > > I've updated the diagram of the filter to be a little prettier in the > > full pdf, and I've also uploaded it as a jpg here: > > > > http://cytomic.com/files/dsp/SkfInputMixing.jpg > > > > i don't see how one analyzes that circuit since c1 and c2 are not connected to > any other impedances. there is no way to determine what the two > capacitors do. it's really a signal flow diagram (like we do with DSP) but with > two mysterious elements added. > > -- > > r b-j r...@audioimagination.com > > "Imagination is more important than knowledge." > > > > -- > 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 -- 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
