With regards noise reduction on ADAU1401
Hi ,
This is an orthodox question.
Could you please let me know if there is a way to implement Noise Reduction block on ADAU1401 (If there a simple block-level implementation it would be helpful)
Basically, we are looking at the 2-way walkie talkie application which takes AD data from MIC and transfer data to Host MCU at 196kHz.
https://wiki.analog.com/resources/tools-software/sigmastudio/toolbox/adialgorithms/noisereduction
Sampling Rate at ADC should be greater than 8kHz but need 196kHz at I2S .
I am looking for ADAU1401 because of cost constraint (196kHz I2S support & and possible to implement Noise Reduction)
Thanking you
With best regards and wishes
Audio Signal Processors
adau1401
SigmaDSP Audio Processors
Hello kabekami,
There is no way to be able to do this with the limited power of this processor. If I adjust your sample rate to be 192kHz, (but you could change the master clock rate to get 196kHz if needed) Then the processor will have only 1/4th of the normal instructions per sample period. 1024/4 = 256 instructions per sample period. The noise reduction algorithm you referenced requires 606 instructions. So you would have to go up to a larger processor. Look into the ADAU1787. It is really small and very low power. It has two processors but one is designed for active noise reduction.
Have a look and let me know your thoughts.
Dave T
Hi ,
Thank you for the information. I am sorry I would like to correct my self it is 192kHz and is not 196kHz.
But get the idea, I am planning to check with ADAU1761 which can be used for noise reduction and use an MCU for converting the Clock rate to meet the need of 192kHz.
Thanking you
With best regards and wishes
Hello kabekami,
Understood. about using the MCU for sample rate conversion. I assume you are running at 192kHZ for latency reasons? So running the 1761 at a lower rate would insert latency.
The NLMS filter in the 1761 will perform better at lower sample rates. Lower rates means 16kHz or maybe 32kHz fs. If they are run faster the filters may have convergence problems.
The Noise Reduction block in the library has to run at 16kHz fs.
So I think you will run into problems along the way or limit your system performance.
With the ADAU1787 the noise reduction filters would be implemented on the fast DSP so the analog audio in to analog audio out would have a latency in the single digit microseconds. Then the SigmaDSP core can be used to update the filter coefficients and do any other GPIO control etc. Then there are also sample rate converters built in so audio can be received or sent at any other rate. It is rather flexible part.
The only small detail is that I do not think we have any example file to give out at this time.
I will be happy to help support your effort if you use the 1761 but I want to be sure you understand the limitations early.
Dave T
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