Hello,
I am using the sliceKIT with the Audio slice (XMOS XP-SKC-L2, XA-SK-AUDIO).
I am trying to modify the bi-quad filter tutorial application to increase the number of filter coefficients (and taps).
What I have done:
-Stripped biquad_simple.c and dsp_biquad.xc so that only the high pass filter is being used (this is working fine).
-Changed NUM_FILT_TAPS in biquad_simple.h to 4
-Added a 4th coefficient in both the a and b vectors in the init_highpass_coefs function
The program compiles and runs, however I cannot hear anything! I need to ultimately use a filter with 100 coefs/taps. Is it possible to modify the biquad program to do this?? Any help on increasing the number of coefficients / taps would be great.
Thank you!
Modify bi-quad tutorial application
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edahle99
- Newbie
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- Joined: Tue Apr 09, 2013 3:37 am
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markb
- Member++
- Posts: 18
- Joined: Tue Oct 08, 2013 1:53 pm
Bi-Quad filters are a sub-class of IIR filters.
IIR filters use feedback and therefore can become unstable, also noise/distortion may become a problem if they are not designed correctly.
Bi-quad filters are used frequently because they have good stability and noise/distortion characteristics.
Adding extra co-efficients to a Bi-Quad will generally create a sub-optimal IIR filter.
Normally more sophisticated filters are designed by concatonating different Bi-Quad units.
IIR filters use feedback and therefore can become unstable, also noise/distortion may become a problem if they are not designed correctly.
Bi-quad filters are used frequently because they have good stability and noise/distortion characteristics.
Adding extra co-efficients to a Bi-Quad will generally create a sub-optimal IIR filter.
Normally more sophisticated filters are designed by concatonating different Bi-Quad units.