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How to plot LPC spectrum

Started by ee41gi July 31, 2007
Hi guys

I have a 10th order LPC with coefficients
[1.000000
-0.473154
0.638717
-0.322174
0.243055
-0.210219
0.417031
-0.452547
0.459508
-0.128858]
and i want to plot the LPC spectrum. on the X axis i want to have the
frequency (0Hz-4000Hz)and on the Y axis the magintude in dbs
How i do that in matlab??
Hi,
use freqz command.

[H,F] = freqz(b,a,N, Fs),
where b = [1]; (coeffs of numerator polynomial)
a = [a0 a1 ... a_p] (lpc coefficients)
which are coeffs of denom polynomial.
N = number of points on the frequency axis
(samples of the spectrum), say 256 or 512.
H is the frequency response of the filter.
Fs is the sampling frequency in Hz.
You seem to have used Fs = 8000.
Use
plot(F,log(abs(H)));
You will get the LP spectrum, which is
(mostly) the envelope of short-time
spectrum.

Bye
Guru

--- ee41gi wrote:

> Hi guys
>
> I have a 10th order LPC with coefficients
> [1.000000
> -0.473154
> 0.638717
> -0.322174
> 0.243055
> -0.210219
> 0.417031
> -0.452547
> 0.459508
> -0.128858]
> and i want to plot the LPC spectrum. on the X axis i
> want to have the
> frequency (0Hz-4000Hz)and on the Y axis the
> magintude in dbs
> How i do that in matlab??
>