A Generalized Biquadratic Filter with Parameter Display

An instrument that couples a new type of biquadratic filter with a picture display capability of s-plane pole and zero locations is described. The filter design allows easily movable, continuous, and orthogonal pole-zero adjustment by the user of all possible stable combinations of biquadratic functions. The resulting instrument represents a uniquely useful educational tool for graphically portraying the effects of network pole-zero positioning on time and frequency domain response.