MediumCalculusca-185

Digital Filter Step

Problem

Take one step of the first-order IIR filter y[n] = b0*x[n] + b1*x[n-1] - a1*y[n-1].

Given the current input x_n, the previous input x_prev, the previous output y_prev, and the coefficients b0, b1, a1, return y[n].

Hint

The feedback term enters with the sign of the difference-equation form, so subtract a1*y_prev.

case 1

in: [1,0,0,1,0,0]

expected: 1

case 2

in: [1,1,0,1,1,0]

expected: 2

case 3

in: [1,1,2,0.5,-0.5,-1]

expected: 2

case 4

in: [0,1,1,1,0,-0.5]

expected: 0.5

Starter codePython

def digital_filter_step(x_n, x_prev, y_prev, b0, b1, a1):
    # Your code here
    pass

4 test cases · run your code against them in the editor