This example shows an implementation of a fourth-order Sallen-Key low-pass filter using Operational Amplifiers (OPAs). The filter design parameters, cut-off frequency (f1) and DC gain (K), are specified using the Design parameters block. Pass-band ripple is predefined to be 1dB using a Chebyshev response. To check the achieved filter frequency response, double-click the Plot frequency response block after running the simulation. In the ideal case, the gain should be equal to 20*log10(K) dB at DC, 20*log(K) at f1, maximum value 20*log10(K) + 1, and -24dB/octave attenuation at high frequency.