topic Clear state FIR filter in Intel® Integrated Performance Primitives

Clear state FIR filter

thorant — Fri, 28 Mar 2008 15:00:23 GMT

Hi

Im using the IPP FIR filter functions. I initialize a filter using FIRInitAlloc. The first time I use the filter it works fine. The second time it igves just garbage. why?
My code is quite simple and looks like this:

st = ippsFIR_32f_I(tmpfi,length,fir_state);
check_err(st);
st = ippsFIR_32f_I(tmpfr,length,fir_state);
check_err(st);

The first call gives correct results, the second only garbage.

Do I need to reset the filter between each time?
I Have initialized my filter this way:

ippsFIRInitAlloc_32f(&fir_state,fir_taps,num_taps,0);

I have not specified a delay line, does that matter?

Thanks

Thor Andreas Tangen

Re: Clear state FIR filter

thorant — Sat, 29 Mar 2008 12:32:24 GMT

An update on the issue; If I reset the delay line between each filtering to zero, everything works fine. But is this supposed to be necesary?

Thanks

Thor Andreas Tangen

Re: Clear state FIR filter

Vladimir_Dudnik — Sun, 30 Mar 2008 20:48:14 GMT

Hello,

there is comment from our expert:

Yes,it is necessarytouse ippsSetDelayLine() ifyou want to start from clear list.

Regards,
Vladimir