Problem on FIR filter in sigma studio

blueray Question

Jul 26, 2018 00:00

I tried to use FIR Filter Block(coefficients calculated by MATLAB) in ADAU1701 and ADAU1452. But I get different results. ADAU1452 provides a linear phase FIR filter, but I don't want it.

I guess FIRSigma300Alg and FIRFiltAlg are quite different. FIRSigma300Alg has an unknown treatment on phase response.

So how can I use FIR Filter Block like ADAU1701(FIRFiltAlg) in ADAU1452 board? I want a clear FIR filter with no other treatment in ADAU1452 board.

Thank you.

Audio Signal Processors

adau1452

sigma studio

fir filter

SigmaDSP Audio Processors

adau1701

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Ken.M Reply

Jul 26, 2018 00:00

Hi. The FIR block for the ADAU1452 should provide the functionality that you are looking for. It is just a straightforward FIR filter with the selected number of tap with the values entered in the table. It is optimized for SIMD, but I use it frequently.

Which version of SigmaStudio are you running?

What is the exact name of the block that you are using?

Ken

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blueray Reply

Jul 27, 2018 00:00

Hi, Ken:

Thank you for your reply!

The block I used is named "FIR Filter" in toolbox, it requires to load table values as filter coefficients.

I run this block in SS v4.1 and v3.15, and received the same results.

The block of ADAU1452 gives a linearized phase response, and the group delay is related to the number of tap. So I guess it is optimized by some technique for common audio applications.

I want to have a filter with nonlinear phase response for noise cancellation. The "FIR Filter" block of ADAU1701 does have a nonlinear phase response(i guess it is not optimized), but this processor is too simple for real applications.

I found the newly developed block "MFxLMS" is only supported by a few processors, such as 1452,1467... I want to use this new block together with a straightforward FIR filter. So can I find a straightforward FIR filter in 1452 or 1467, or other similar processors?

Thanks and regards!

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