Some questions about cepstrum are here.

Let us take a example to illustrate it.

Suppose a speech signal x(n) with length 256, n = 0--255, with fs =
8000, thus the sampling period is 1/fs = 0.0125s.

Let's take FFT tranform with 1024 length, result a symmtrical
spectrum ,also in 1024 length.Then take absolute value and log
computation, get 1024 length sqrt power spectrum in log domain.
Finally taking IFFT transform, result 1024 points symmtrical  cepstrum
c(m), m =0-1023.

1. c(m) must be a even-symmetrical vector,with a length of 1024.  The
independent variable m, which is called quefrency, is in time
sense.Then how to correspond the quefrency with the real time scale?
That is to say, how much is the sampling period of c(m)?

2.Where is the beginning of c(m)? That is to say,which point is its
real head? m = 0, or m = 1024/2 = 512?

Cheers
HyeeWang@gmail.com

On May 19, 10:29=A0pm, HyeeWang <hyeew...@gmail.com> wrote:
> Some questions about cepstrum are here.
>
> Let us take a example to illustrate it.
>
> Suppose a speech signal x(n) with length 256, n =3D 0--255, with fs =3D
> 8000, thus the sampling period is 1/fs =3D 0.0125s.
>
> Let's take FFT tranform with 1024 length, result a symmtrical
> spectrum ,also in 1024 length.Then take absolute value and log
> computation, get 1024 length sqrt power spectrum in log domain.
> Finally taking IFFT transform, result 1024 points symmtrical =A0cepstrum
> c(m), m =3D0-1023.
>
> 1. c(m) must be a even-symmetrical vector,with a length of 1024. =A0The
> independent variable m, which is called quefrency, is in time
> sense.Then how to correspond the quefrency with the real time scale?
> That is to say, how much is the sampling period of c(m)?
>
> 2.Where is the beginning of c(m)? That is to say,which point is its
> real head? m =3D 0, or m =3D 1024/2 =3D 512?
>
> Cheers
> HyeeW...@gmail.com

Much to my surprised, why not a little response for such two ordinary
cepstrum questions?

Are they not clear or illogical?

Puzzled!

HyeeWang