State variable filter, the digital implementation

[Yansi]

Hello,
supposed I have to implement this, the State Variable Filter:



What I do not understand clearly, is whether I have to implement this exactly to get the desired behavior, or whether I can toy a bit with the integrators to make implementation somewhat more efficient.

What I mean is this: There are two forms of the digital integrator.  The implementation of SVF above uses both types. The Question is, whether I could for example replace the second integrator with the other form. Will it still work as intended?



The same I could ask with regards to the bandpass output: Could I obtain the output just after the z^-1 delay block? (The signal will be obviously the same, but 1 sample time delayed).

That would for example make for a nice optimization using a MAC instruction on a real microprocessor, as I could implement this whole block as a single MAC this way:

Code: [Select]

y[n] = y[n-1] + Fc*x[n]
And same for the other integrator, the Lowpass output respectively.