- #1
BriWel
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I have a question which is to design a filter of the form:
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;
Z2H(z) = (z - exp(i*(pi/2))[ )(z - exp(-i*(pi/z)) )
When expanded and simplified this gives
H(z) = z2 + 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?
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;
Z2H(z) = (z - exp(i*(pi/2))[ )(z - exp(-i*(pi/z)) )
When expanded and simplified this gives
H(z) = z2 + 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?