A 4th order low pass Butterworth filter may be implemented using two Sallen-Key stages, as shown in the circuit below. V. in M RIA Part 1 M RA CIA CA RA vo(s) Vin (s) H(s) = + s + s -4A w (RC + RIB The prototype transfer function, which has a gain of 3dB down from the maximum, at the cutoff frequency of w = 1 rad/s, is as follows: M RB CIB 4 (s +0.76537s + 1)(s + 1.8477s + 1) Remember that the transfer function of each second order low pass Sallen-Key stage is given by: Using capacitor values of CA = C2A = C1B = CB filter, to obtain a cutoff frequency of 1 rad/s. K RRCC 1- K + RC RC + = R3B 2B 1 R RC C RAB ; M K = 1 + V. R4 R3 0 ... (1) ... (2) 1F, calculate remaining component values for this