Remove audio feedback with ad1940(dsp)

Hello leemaster,

So I am a little confused. You already have an old design using this very old AD1940 and you want to change the program?

Or, do you want to design a new board using some other DSP with the features you mentioned?

Do you have a project file you are using? Can you share it on the forum?

Dave T

Hello DaveThib

Thank you for your answer.

You already have an old design using this very old AD1940 and you want to change the program?

--> NO. It is being designed using ad1940.

I uploaded the project file.

I'm still studying, so I just explained it in the project file.AD1940_QuickStart.dspproj

Hello leemaster,

I have put together some of the basic functions you asked about. I cannot test this since I do not have an AD1940 eval board handy. This processor is VERY old. It is the first SigmaDSP we ever produced. Since then we have some out with the Sigma100, Sigma200, Sigma300 and Sigma350 generations of processors. The AD1940 has only around 1500 instructions per sample period. The project I just put together uses 471 instructions. 

Since I could not test it I am not certain if I connected the audio and the zero level correctly to the mux that switches between the signal and the mute ( zero). 

Regarding the feedback suppression. This is not easy to do and doing it for this processor will be very limited. How this can be done will very much depend on your application. Where the mics are, where the speakers are, the room acoustics etc. You can search the forum for feedback suppression where we have had some discussions on how to do it. You will be very limited by using this processor. 

Dave T

AD1940_QuickStart-DSP Edits.dspproj

Hello leemaster,

I have put together some of the basic functions you asked about. I cannot test this since I do not have an AD1940 eval board handy. This processor is VERY old. It is the first SigmaDSP we ever produced. Since then we have some out with the Sigma100, Sigma200, Sigma300 and Sigma350 generations of processors. The AD1940 has only around 1500 instructions per sample period. The project I just put together uses 471 instructions. 

Since I could not test it I am not certain if I connected the audio and the zero level correctly to the mux that switches between the signal and the mute ( zero). 

Regarding the feedback suppression. This is not easy to do and doing it for this processor will be very limited. How this can be done will very much depend on your application. Where the mics are, where the speakers are, the room acoustics etc. You can search the forum for feedback suppression where we have had some discussions on how to do it. You will be very limited by using this processor. 

Dave T

AD1940_QuickStart-DSP Edits.dspproj

Hello DaveThib

Sorry my answer was late.

I want to change the design.  I'm trying to use the adau1452 chip

input mic 4, output 1, Echo Cancellation

I've looked for the data, but it doesn't work.

Thank you for your help.

ADAU1452.dspproj

Hello leemaster,

There are a couple of posts you can read for some ideas.

(+) How to determine which frequency band has highest magnitude - Q&A - SigmaDSP Processors and SigmaStudio Development Tool - EngineerZone (analog.com)

This one is specifically using a 1452 and there is an example project.

(+) How to eliminate feedback in Sigma DSP ADAU1452 - Q&A - SigmaDSP Processors and SigmaStudio Development Tool - EngineerZone (analog.com)

Dave T