## I need to find difference equation and frequency response

### Noel (view profile)

on 15 Nov 2011

Given H(z)=(-3+z^z-1)/(1+2z^-1+3z^-2)

a) Find the difference equation

b) Plot the frequency response

Naz

on 15 Nov 2011

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### Walter Roberson (view profile)

on 15 Nov 2011

However, it appears to me that your equation probably cannot be analyzed through these techniques, as it is not in the form of a ratio of polynomials. The z^z term is going to lead you to a lot of problems.

### Naz (view profile)

on 15 Nov 2011

Difference equation (I assume that z^z-1 should be z^-1):

```3y[n-2]+2y[n-1]+y[n]=-3x[n]+z[n-1]
```

Frequency response:

```B=[-3 1];
A=[1 2 3];
[H,W] = freqz(B,A);
plot(W,H);
```

Naz

### Naz (view profile)

on 15 Nov 2011

The frequency is normalized to pi

Walter Roberson

### Walter Roberson (view profile)

on 15 Nov 2011

My speculation was that the z^z-1 should be z^2 - 1 but that doesn't make sense with the leading -3 . So I still don't know what was intended.

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