Second order Rauch low-pass filter

This schematic simulates a second-order low-pass filter based on Rauch's structure. The left part of the circuit consists in an adder creating a noisy signal. The base signal is 10Hz and the noise is 10kHz. The right side of the circuit is the Rauch structure. All resistors should be of equal value. The cutoff frequency is defined as fc =1/(2*pi*R*sqrt(C1*C2)). IN this case, the default values give around 159Hz, which is good for filtering a 10Hz signal.