Describing-function evaluation of single and double amplifier non-linearities in active filters

A first-harmonic describing-function technique is developed for the computer-aided evaluation of the large-signal performance of single and two-amplifier filters. This new numerical approach leads to more realistic determination of the critical jump provoking input voltage as well as the exact extent of hysteresis overhang. In the case of double amplifiers, the responsibility of each non-linearity in causing jump reasonance is identified. Gain and phase frequency responses are presented for n representative sample of active-RC and active-R networks showing close agreement between theory and measurement.