ABSTRACT
The simulation of a resistively terminated ladder LC filter is desirable, because it leads to active RC filters with very low sensitivity in the passband. This simulation can be achieved either by simulating the inductances by means of operational amplifier (opamps), resistors and capacitors, or by simulating the operation of the ladder. The opamps in the first case are used to realize gyrators, generalized impedance converters, or frequency-dependent negative resistors. In the second case, the opamps are used as integrators, lossless and lossy, summers, and sign-reversing elements or as parts of active biquads. The low passband sensitivity of the filters designed using the latter simulation approach is their most important characteristic. A very important advantage of active RC filters is the availability of the prototype ladder LC designs. The well known lowpass Butterworth, Chebyshev, Bessel, and Cauer filter functions have been designed as resistively terminated ladder LC filters and tabulated.
