TOPIC:

hi,
is it possible to use biquad filters to say increase or drecrease the output by say 3 db using biquad without using the digital output gain. How do you do this? Thanks

Lito

I believe if you set b0 to 1.414 or 0.707 (others at zero), that will do it.

Not sure why though - ?

@ Lito,

Yes, you indeed can do it:

If you want to combine Gain (GdB) to one of your biquad filter, there is a simple way. Simply "Multiply" your numerators (all b0, b1, b2) to the linear gain value. (Glin)

e.g. H(z) = Glin * (b0 + b1z-1 + b2z-2) / ( 1+a1z-1 + a2z-2)
So Glin = 10^(GdB/20)

DevTeam