adaptfilt functions

I use different adaptfilt functions for my project, but I have to a little bit change them. Therefore I kindly ask somebody to advise me, how I can view these algorithms mathlab original code or how I can change their coefficients before filtering:

For example I tried to add >ha.coefficien(1)=0 command with changing persistentmemory before filtering:

>ha = adaptfilt.lms(32,mu); >hd.persistentmemory = true; >ha.coefficien(1)=0; >[y,e] = filter(ha,x,d);

But it didn't work and coefficients keep intitial codition.

Thanks in advance for your advice

Answer 1

[Honglei Chen]

Hi Peter,

Maybe I understand it wrong but you cannot directly change LMS filter's coefficients because it is updated in each iteration. To specify the initial filter coefficients and states, you can use the syntax

H = adaptfilt.lms(L,STEPSIZE,LEAKAGE,COEFFS,STATES)

See

help adaptfilt.lms
doc adaptfilt.lms

for details.

HTH,

[Shravan Anand Komakula]

Undefined variable "adaptfilt" or class "adaptfilt.lms".

ha = adaptfilt.lms(30,mu);

"How to deal with this error"

[Honglei Chen]

Do you have DSP System Toolbox? You need that to be able to access adaptfilt.

HTH