Find output of digital filter given input and transfer function?
Standard difference equation of a biquad: y[n] = b0*x[n]+b1*x[n-1]+b2*x[n-2]-a1*y[n-1]-a2*y[n-2];

Initialize all x[n], y[n]  to 0 for n &lt; -1

b0,b1,b2 are 0.86 -1.72 0.86 (numerator) 

a0,a1,a2 are 1 -1.71 0.73 (denominator)