TAS5782M: Questions for TAS5782M PPC3 EQ Gain Calculation

Hi Jacky,

Sorry for the delay. As to your questions:

1. Gain of BQ in EQ of TAS5782 is not reflected in the 5 coefficients but in following gain BQ. Please refer to applicaton note TAS5782 Process Flows for more as well as PPC3 I2C Monitor for more details as bellow:
2. As to formula for the 5 coefficients, please refer to:

• • Get the b0, b1, b2, a0, a1, a2 parameters from the formula Audio-EQ-cookbook.
  •  Then follwing the file  
    Fullscreen TAS5782 EQ coefficient Normalization.txt Download

    %Step 1: Get the b0, b1, b2, a0, a1, a2 parameters from the formula Audio-EQ-cookbook.
    %Step 2: Normalize the b0, b1, b2, a0, a1, a2 to get the b0_a0, b1_a0, b2_a0, a0_a0, a1_a0, a2_a0, k       
    
    	   b0_a0=(b0/a0);                 %1.31 format
            b1_a0=(b1/a0)/2;             %2.30 format
            b2_a0=(b2/a0);              %1.31 format
    
            k1=max(abs([b0_a0,b1_a0,b2_a0]));        % Divide by the max value to avoid overflow
            if k1>0.99999988079071044921875;
                k=k1/0.99999988079071044921875;
                b0_a0=b0_a0/k;
                b1_a0=b1_a0/k;
                b2_a0=b2_a0/k;
            else
                k=1;
            end
    
            a0_a0=(a0/a0);
            a1_a0=(a1/a0)/2;               %2.30 format
            a2_a0=(a2/a0);                   %1.31 format
    
    % Fill b0_a0, b1_a0, b2_a0, a0_a0, a1_a0, a2_a0 in PPC3 for configuration.	
    		
    		
    % if you want to translate the coefficent to Hex vaule rather than
    % using our PPC3, you can use following formulat to get the HEX coefficient
    % and then wirte them to related register
    
    Step 3: Transfer the b0_a0, b1_a0, b2_a0, a1_a0, a2_a0 to 32bit 2's complement
    [B0,B1,B2,A1,A2] = dec2hex(mod(min(round(2^(32-1)*[ b0_a0, b1_a0, b2_a0, a1_a0, a2_a0]),2^(32-1)-1),2^32));
    
    Step 4:  Write the [B0,B1,B2,A1,A2] to the right register address, multiply the value �k� back in the step 2 to the volume register or the b0, b1, b2 of 15th BQ. 
    

     to get your coefficients.

For more details, please contact me.

Regards,

Alix Wan.