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Remembering NLMS block values.

SigmaDSP & SigmaStudio LukasSE Jul 27, 2015 00:00 1 replies Original on forum ↗
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LukasSE Question
Jul 27, 2015 00:00

I have a NLMS block in use in my project on a ADAU1761. This seems to work fine. The block learn about the reflections it should cancel. But after a reset this learned information (filter coefficients) is lost.

I saw a few screen shots on this form where the NLMS block contain a button that show the coefficients. But when I use the block this button is not available. Also in exported C code I can’t see a declaration for the coefficients. The space used for the coefficients is not so difficult to find:

#define MOD_NLMS1_ALG0_LMSALG1RMSTABLEBASE31_ADDR 55

#define MOD_NLMS1_ALG0_LMSALG1RMSTABLEBASE31_FIXPT 0x00020000

#define MOD_NLMS1_ALG0_LMSALG1RMSTABLEBASE31_VALUE SIGMASTUDIOTYPE_FIXPOINT_CONVERT(0.015625)

#define MOD_NLMS1_ALG0_LMSALG1RMSTABLEBASE31_TYPE SIGMASTUDIOTYPE_FIXPOINT

#define MOD_NLMS1_ALG0_LMSALG1CCZM0_ADDR 311

#define MOD_NLMS1_ALG0_LMSALG1CCZM0_FIXPT 0x00800000

#define MOD_NLMS1_ALG0_LMSALG1CCZM0_VALUE SIGMASTUDIOTYPE_FIXPOINT_CONVERT(1)

#define MOD_NLMS1_ALG0_LMSALG1CCZM0_TYPE SIGMASTUDIOTYPE_FIXPOINT

I like to memorize the learned information. That way, I’m able to restore the last known information after a reset, giving better results just from the start.

Could I simply copy all data, or are the some things I have to take care off?

Thanks, Lukas

Audio Signal Processors

SigmaDSP Audio Processors

adau1761

DaveThib Reply
Apr 21, 2016 00:00

Hello Lukas,

Sorry I missed your question until now. There is a post on the forum that will help you extract the coefficients and then you can have your system controller initialize them at bootup time.

https://ez.analog.com/message/113178#comment-113178

I hope this helps.

Dave T