FPGA Notch Filter Scaled Coefficients to SGL

[charlie87]

Hi,

I am working on digital notch filter on FPGA. I am using the well-known Notch Filter.vi and the Notch Coefficients in RT System. I wanted to see the Notch algoritm so I opened the Notch Filter.vi, see below. I would like to know the notch coefficients in floating point or fixpoint format to investigate the notch properties but I am not able to recalculate them. Could anyone explain to me how to do it ?

[GerdW · Accepted solution]

Hi charlie,

do you see that "out shift" of -13 in your image?

All the coefficients are scaled to integers with 2^13. To get the correct FXP result the output gets scaled by 2^-13 in the end.

Using integers is much easier in the FPGA and all you need is to apply some scaling to your numbers…