General purpose biquads optimized for dynamic range and low noise

In this paper two general-purpose (GP) biquadratic filters are analyzed and optimized. The design equations for both filters are given, and the methods used to optimize the dynamic range and reduce the noise are described. On one example of the 2/sup nd/-order Butterworth filter, PSpice analyses were carried out, and a comparison of noise, referred to the input, is given. The dynamic range is optimized such as to have the same signal level at each amplifier output. Both optimization procedures are highly effective and can be applied to the similar filter design problems.