Sensitivity optimization method for 4th order CBQ structure LP filter

This paper describes the design and optimization method for a 4th order low-pass filter designed as a cascade of biquarts and approximated by Butterworth. Schoeffler sensitivity, multiparameter sensitivity measurement, and Monte Carlo analysis were used for sensitivity measurement, filter tuning, and optimization confirmation. The constraints on the filter characteristics due to the Butterworth approximation are also presented, together with the constraints on optimization to obtain a narrow range of values for the filter elements. Three different types of optimization parameters were used to confirm the optimization method. Finally, a 4th order low pass filter with a cascade structure of biquarts was compared to a 4th order filter without feedback and confirmed to have lower sensitivity.