Synthesis of nonrecursifs filters or FIR
The synthesis consists in determining the structure of a filter according to the frequency answer which one wants to obtain.
1. Determination by identification in a known structure
|Let us suppose that one likes to make a low band filter of frequency of cut||,one can then set the|
|structure realized with the following FIR filter :||.|
|answer of this filter :||, or :|
One has so this frequency answer :
So these answere :
One notices: fc=fe/4. It is thus necessary to fix fe to have the wished frequency of cut.