Filter Reversing
Given
The coefficients from the spec
Stage 1 filter
Cookbook definition of a high-shelf filter
We need an extra variable,
Reversing the high-shelf coefficients
Here, we can cheat because we know from the diagram in the spec that
To solve for
We'll need this form of
Now, to solve for
Time for
And
Stage 2 filter
Cookbook definition of a high-pass filter
Reversing the low-pass coefficients
This filter should be a lot easier to reverse due to the relative simplicity of the
Again, we start by solving for
Substitute:
We solve for
And then
And