Recursive least squares and LPC

Started by kartikaye83 August 5, 2008
Hi All,

I have implemented a 10th order Recursive Least Squares filter on
Matlab for speech and am comparing the weights thus obtained with the
weights using the LPC function.

Then I am comparing the speech quality using PESQ MOS values for
various speech files.

I run my RLS for lambda=1 (forgetting factor)
and delta=.02 (regularization factor), which gives the best performance.

my questions are -

1) I get PESQ MOS values like 4.47 and 4.45 for the estimated signal
using LPC. Are these values too high ?? Is there a limitation of PESQ
MOS in this case that I should be aware of?

2) For a particular speech file, the RLS weights and the LPC weights
match upto 3 decimal places, but the PESQ MOS value for LPC is 4.47
and that for RLS is 4.07. How come there is such a huge difference
between the two if the weights match almost perfectly?

It would be great if someone can help me with this.