Active R filter : a new biquadratic with four output terminals
Sun Zhi-xiao · International Journal of Electronics · 1983
A new biquadratic active R filter is presented which uses only resistors and operational amplifiers. It can be all integrated. It realizes all five functions of biquadratic function, i.e. lowpass, bandpass, highpass, bandatop and allpass function (or LP, BP, HP, BS and AP function) at four different output terminals. It realizes at least two functions at each output terminal. The circuit has very low sensitivities with respect to all passive and active parameters, and is suitable for low or medium Q, high frequency applications. Design equations for each class of filters are given. Laboratory experimental results confirm the validity of the theory.