Generalized STFTA generalized STFT may be defined by 
This filter bank and its reconstruction are diagrammed in Fig.11.35.
downsampling factor for the output of the th channel filter: For critical sampling without aliasing, we set . The impulse response of synthesis filter can be regarded as the th basis signal in the reconstruction. If the are orthonormal, then we have . More generally, form a biorthogonal basis.
Dyadic Filter Bank Design