Hi Senoadiwibowo,

Yes this is what I want, Thank you very much

regards,

Thanks for your reply DSP,

Actually, my question is about magnitude frequency response which was not display correctly on it.
I dont know whether the R&D module reverse it or the RBJ formula is not correct.
Please refer to attachment file for your reference, frequency response of LPF, HPF and Notch ...

Hi,

I have question regarding biquad frequency response, I created filter base on RBJ filter cookbook and use biquad frequency response (R&D) module but I got very strange frequency response result for LPF, HPF, BPF, and notch filter.
why those filter response showed reverse? I mean the response ...