Hi John,

I am now trying to control the "Genera Eq" from my MCU.On the calculation of the coefficients of the different filter type,it seems to be two version of formulas of the "Parametric" type filter by referring to the "SigmaStudio Help".In the "Filters" part the formulas used to calculate the coefficients showed as the image below:

Similarly but not the the same,while in the "EQ Algorithm" part,as showed in the image below,the formula on the "alpha = sin(w0)/(2*Q)" is different from the above with the "A" coefficient excluded here.

In my sigma studio,the "Parametric" filter type was chosen,but the formulas to calculate out the 5 coefficients of it are according to the "Peaking" filter,for which the "Transfer function" is the same as the "Parametric" filter.Even though,after altering the "Parametric" filter to "Peaking" filter the 5 coefficients to be sent out while tuning from the sigma studio are different.

All in all,I am just confused by the calculation formula of the 5 coefficients.Why do I have to control the "Parametric" filter with the formula of the "Peaking" filter?

Best Regards,

Liang

Hi Liang,

Please refer to the attachment

FilterMathCalculations.pdfin the below mentioned FAQ for the actual equations used to compute the filter coefficients.http://ez.analog.com/docs/DOC-1819

To compute the coefficients for 'Peaking' filter, use the same equations as 'Notch' filter from the document except for the below changes.

B0 = gain * (1 - b)B1 = 0B2 = gain * (b - 1)Best Regards,

John