Bandwidth expansion in G.723 and G.729

Started by Cool Dsp June 11, 2003


I am new to Speech Coding. I was reading through the ITU-T specs for G.723 and
G.729. Can anyone enlighten me on the following aspects:

The importance of bandwidth expansion after LPC estimation?

Why this expansion is different for G.723(7.5 Hz) and G.729(40 Hz)?


Warm Regards,


Bandwidth expansion is done inorder to bring the poles of the LPC filter onto
the unit circle of the Z plane.
This is done for increasing the stability of predictor co-effecients.

But I don't know why it is different for G.723 and G.729

With Rgds
Chetan k.