Test canonical form IIR

Unfortunately, I am not able to send my .dspproj, my uploading doesn't work, I don't understand why.

Hello,

Unfortunately, the Stimulus -- Probe tool won't accurately predict the response of custom IIR filters. This post explains what this tool can and cannot do.

To upload a .dspproj file, you need to "zip" it first.

Best regards,

Bob

Many thanks Bob. Here is my file.

IIR_form_II.dspproj.zip

Hello,

Perhaps you could use Lookup Tables (LUTs) to store your filter parameters as shown below:

There may be some clicks or pops with filter changes, as this method doesn't include slewing -- but simply placing first-order lowpass filters between the LUT outputs and multiplier inputs may help with that.

The use of DM0 or DM1 becomes significant with large delays -- recent SigmaStudio versions allow you to choose. It probably doesn't matter for the one-sample delays which the Feedback blocks impose.

Best regards,

Bob

IIR_form_II_LUT.zip

Thank you Bob for your support.

Obviously, I have got another issue with my tests with a FIR this time and with the parameters here below:

Hz Gain

0 0
1990 0
2000 100
5000 100
5200 10
8000 10
8200 0

My stimulus with probe doesn't work, I would like to look at the curve but not possible, however that should work with a FIR module ? In sweeping the generator, it seems good on my output DAC.

What is the wrong in what I realize ?

Thank you.

Kwanja

Sorry, I forgot to put my project :
IIR_form_II.dspproj 2.zip

Hello Kwanja,

I inserted your filter an old project of mine which measures frequency response on a ADAU1452 board and found it compares nicely to the Stimulus-Probe results. Your most recent thread reports that you have it working as well, so there was really nothing wrong with what you were doing. My response in your other thread explains the high gain of this filter.

To show that the Stimulus-Probe tool really works with FIR filters, here's its estimated response of a 175 tap windowed-sinc 4 KHz telephone lowpass filter:

BR,

Bob