DEMO_FILTERBANKSYNCHROSQUEEZE Filterbank synchrosqueezing and inversion
The demo shows that the synchrosqueezed filterbank representation can be
directly used to reconstruct the original signal.
Since we do not work with a filterbank which forms a tight frame
(its FILTERBANKRESPONSE is not constant) the direct reconstruction
(mere summing all the channels) does not work well. We can fix that by
filtering (equalizing) the result by the inverse of the overall analysis
filterbank frequency response.
Figure 1: ERBlet spectrogram (top) and synchrosqueezed ERBlet spectrogram (bottom)
The signal used is the first second from GSPI. Only the energy of
the coefficients is show. Both representations are in fact complex and
invertible.
Figure 2: Errors of the direct and the equalized reconstructions
There is still a small DC offset of the signal obtained by the direct
summation.
References:
N. Holighaus, Z. Průša, and P. L. Soendergaard. Reassignment and
synchrosqueezing for general time-frequency filter banks, subsampling
and processing. Signal Processing, 125:1--8, 2016. [1]http ]
References
1. http://www.sciencedirect.com/science/article/pii/S0165168416000141
Url: http://ltfat.github.io/doc/demos/demo_filterbanksynchrosqueeze.html
Package: ltfat