In the past decade, the application of orthonormal or paraunitary (PU) matrices to subband coding has drawn considerably attention. In this paper, we will study signal compression using unimodular matrices. Like PU matrices, unimodular matrices have FIR inverse. However, unimodular matrices do not have the energy preservation property. Applying unimodular matrices to subband coding is not always a good choices as quantization noise might be amplified and coding gain can be less than one. We introduce a new structure for unimodular coders. The new structure consists of a closed-loop vector DPCM structure followed by a transform coder. Using such a structure, it is shown that the coding gain of unimodular coders is never less than 1. Simulation example shows that despite having the smallest system delay, unimodular coders have a better performance than subband coding with the same complexity for AR(1) input.
|Journal||Proceedings - IEEE International Symposium on Circuits and Systems|
|State||Published - 1 Jan 2002|
|Event||2002 IEEE International Symposium on Circuits and Systems - Phoenix, AZ, United States|
Duration: 26 May 2002 → 29 May 2002