Hi everybody, I'd like to know if SigmaStudio allows a small code programming solution. For example, I'd need to write Filter Funcionality of a Warped FIR filter, an iterative procedure of sums and products between samples of previous time. This costs one program code line in Matlab for instance. I'm looking for a code-programming way (for Mathematical procedure) to program the chip, if it is feasible.

Thanks to all.

Regards,

leonxp

Hi leonxp,

I'm afraid that the short answer is no, there isn't a C compiler or Matlab-like script for SigmaDSP. It is possible, however, to implement a warped FIR filter by building a structure like that of a FIR filter, substituting all-pass filters for the usual unit delays:

As you know, although the structure looks like FIR, the all-pass filters impart an infinite impulse response.

The ADAU1701 can fit about 80 of these stages. For the example below I set the first coefficient to +1, the last to -1, and all others to zero, to make a comb filter. In the usual FIR version using delays, the nulls repeat at equal Hz intervals. The warped version's nulls get wider apart with increasing frequency, as shown:

The attached project file includes this filter with the frequency sweeper that made the graph.

Best regards,

Bob