Hi,

I am having problems understanding the calculation of distortion operands like DISG, how the reference is used, how the calculation is done etc... ? I have checked the user manuel but it is note helping me, for example in DISG explanation it says 'The method used and assumptions made for DISG calculations are common to all operands that calculate distortion', but I have not found anywhere the method explained, except in Grid Distortion chapter. Did I miss something ? Could you share with me some details on the calculation, how the reference is used etc ? 

Thank you in advance,

Best regards,

Nicolas