who can provide some material for a filter with eight terminals?

barry said:

I have an animal here, it has four legs and a head. Can you tell me what it is? No? You mean you need something like a picture?

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superleaf said:

I got a analog filter here,but this structure of the filter is a little weird,it has four input terminals and four output terminals,i have never seen this structure before,who can provide me some materials about this structure,or tell me how it works with eight terminals.Thank you very much!

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LvW said:

There is a filter structure called "Fleischer-Tow universal filter" with three input terminals and three output nodes. It contains three opamps (integrator, damped integrator, inverter) and allows all classic trnafer functions like lowpass, highpass, bandpass, bandstop, allpass, elliptical low/highpass. May be your circuit contains one additional opamp fur buffering or combining some outputs.
The basic functions are realized by connecting all or only some of the inputs with the input signal.

That is the only multi input topology I can remember.

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superleaf said:

Thank you very much,so ,could you provide some paper related to this kind of filter,i can't find any information from Internet.^_^

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erikl said:

See this book: View attachment 81757 chap. 5.6.3 .

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