I'm using the IIR hardware accelerator of the DSP with it's own example program provided by analog devices.
I have implemented a 6th order IIR low and highpass filter with cutoff frequency 800 Hz. As shown in the pictures, the noisefloow with the highpass filter is much higher than the one with the lowpass filter. Has anyone got an idea where that might come from?
Hi,It seems you are using ADSP-21489. Do you see this problem on EZ-Kit ? BTW, can you let me know how you are generating the filter coefficients. Are you using any filter coefficient generating tool like MATLAB or GNU Octave? Is it possible for you to check whether the coefficients you have provided yields the same result on any other tool(like MATLAB etc.)?Are you using VDSP or CCES?Did you observe noise when changing the cutoff frequency or with any other order filter?Regards,Lalitha S
Sorry for my late reply.
Yes I see the problem on the EZ-KitCoefficients are generated in MATLAB with the Octave file included in the readme file of the VDSP Talkthrough IIR Accelerator example. Coefficients are generated by the "butter" function.
I'm using VDSP
In MATLAB the filter looks perfect. No noisefloor.
When i raised the Cutoff Frequency (100, 1000, 10000Hz) the noisefloor decreased.
Hello ,Apologies for the delay. Were you able to get going. Let me know if you are still facing any issues.Regards,Lalitha.S