- #1

BriWel

- 3

- 0

y(n) = a(0)x(n) + a(1)x(n-1) + a(2)x(n-2) to remove a narrowband disturbance with frequency f0 = 70Hz.

The sampling frequency, fs is 280Hz.

I've made an attempt at answering it, but don't think my result is correct:

w0 = (2*pi)* (f0/fs) = pi/2

I then calculate the zeros of the filter from the definition of w

z1 = exp

^{(i*(pi/2))[}

z2 = exp

^{(-i*(pi/z))}

where i = sqrt(-1)

The transfer function of the filter is therefore;

Z

^{2}H(z) = (z - exp

^{(i*(pi/2))[})(z - exp

^{(-i*(pi/z))})

When expanded and simplified this gives

H(z) = z

^{2}+ 1, so the filter function

y(n) = x(n) + x(n - 2),

giving

a(0) = 1

a(1) = 0

a(2) = 1

Which I'm pretty sure is wrong. Can anyone tell me where I have gone wrong?