I would like to know if there are any calculations for filter co-efficients of 7 band peq , in sgtl5000.I am using to eliminate noise in the frequency band 800-3k hz
Yes, for the codec STL5000 IC,you can set up the parameter equation via I2C interface, the PCM data cab be transferred via I2S interface. For the IIR filter coefficent, it is dependent on the center frequency, sampling frequency, band width..., you have to calculate then yourself and send the coefficent via I2C interface.
I attach the UM of STL5000, pls refer to section 7-BAND PEQ PRESET SELECTION.
Hope it can help you
Thanks for your help,
But I am not able to filterout the frequency range entirely, the noise still exists.
I suppose that the IIR coefficients are inappropriate. I attach an application note about the band-pass digital filter design.
thanks for your reply Rong,
I am aware of the concepts of digital and analog band pass filters and their frequency responses.Anyways your application note on the band pass filter design gave much detailing only on the formulas,My doubt is do I miss out any register setting on SGTL5000, so as to enable the peq block or some sequence in setting the registers.I have added below a pseudo code of what registers I am setting to enable peq . Please correct me if I missed out something.
DAP_CONTROL->DAP_EN = 1
DAP_PEQ->EN = 0x01
DAP_AUDIO_EQ->EN = 0x01
write the co-efficient registers for lpf of cut-off frequency 800,
I am using this but frequencies above 800, even above 3k hz are available as I see in an equalizer application in my PC,
I suppose that the frequencies above 800 hz must be cutt off or attenuated.But that doesnt happen.
Thanks in advance for your help.
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