Is there any fft block for 1701_dsp?

Hello,

I'm afraid there's no FFT for the Sigma100 chips (AD1940, ADAU1401, 1701). These are designed strictly for stream processing, thus cannot execute a branch or loop (other than looping back to the top of a signal flow; in fact any unused instruction space is padded with NOPs). Typical FFT code, like the examples shown here, are loaded with branches and DO loops -- so FFT is just plain impossible on a ADAU1701. The ADAU1452 and above feature FFT blocks.

This being said, you can do some real-time frequency analysis on a -1701. There's a seven-band level detector block, for example. And you can arrange a set of filters to separate frequency bands. Where I work we included a basic RTA in our 12-in, 4-out PA mixer to assist with its setup -- and it runs entirely on ADAU1701s, one for each pair of inputs.

Best regards,

Bob

Hello Bob,

Where are the FFT blocks on ADAU1451 in Sigma studio ? How can we proceed ? I don't see them under Sigma studio 4.4 ?

Best Regards,

Kwanja

Hello Kwanja,

It is located in the Block Processing schematic tab. When you click on this the toolbox will change to the cells that are available for block processing.

Then click and expand the Frequency Domain section of the library.

Dave T

Super, Thanks !