universal active filter - five filter modes from one IC

universal active filter elektor january 1984 Not so very long ago, active-filter ICs would have seemed about as likely as pocket washing machines but today they are, if not exactly commonplace, certainly readily available. With the aid of very few extra components the Reticon R5620 can form the basis of a versatile active filter for use in audio or synthesiser applications - or as an extra piece of test equipment for use in the workshop. All this — and not a single coil in sight! universal active filter five filter modes from one IC The full title of the Reticon R5620 is "a second order switched capacitor filter network". It is able to implement the five basic filter modes: low pass, band pass, high pass, all pass, and notch. One further, very useful, function of this IC is that of a programmable sine-wave oscillator. One could be forgiven for expecting to find all this in a large IC of the LSI variety. In fact, it is all contained in an 18-pin package thanks to one further feat...