Filter Co-efficient Calculation

Dear Team,

We have tried calculating filter coefficients theoretically with following parameters

Parameters:

Filter Type : General Eq (2nd order ) High Pass Filter

Sampling frequency(fs) : 48000Hz

Cutoff frequency(fc) : 4Hz

Q factor : 0.7

Gain : 0

We have referred formulas from General 2nd Order High pass filter section from analog devices website. The filter coefficients calculated is different from coefficients observed in capture window of sigma studio.

Kindly find the observations as below

Coefficients observed in capture window

Coefficients calculated in excel sheet

EQGenFilterDPS300Alg1B2_1

0.99962610006332

0.99962607220141

EQGenFilterDPS300Alg1B1_1

-1.99925214052200

-1.99925214440281

EQGenFilterDPS300Alg1B0_1

0.99962610006332

0.99962607220141

EQGenFilterDPS300Alg1A2_1

-0.99925225973129

-0.99925228142940

EQGenFilterDPS300Alg1A1_1

1.99925202131271

1.99925200737623

Also when we try to load the calculated coefficients directly in "IIR Coefficient" mode available in General Eq (2nd order ) different values are observed in capture window

Coefficients observed in capture window

IIR Coefficients Loaded

EQGenFilterDPS300Alg1B2_1

0.99962610006332

0.99962607220100

EQGenFilterDPS300Alg1B1_1

-1.99925214052200

-1.99925214440300

EQGenFilterDPS300Alg1B0_1

0.99962610006332

0.99962607220100

EQGenFilterDPS300Alg1A2_1

-0.99925225973129

0.99925228142900

EQGenFilterDPS300Alg1A1_1

1.99925202131271

-1.99925200737600

Your explanation of these observations is awaited.

Regards

Hermione