Quadraphony: Developments in matrix H decoding
Abstract
The basic form of decoder is a complexcoefficient linear matrix, but this has an inherent lack of separation between the output signals. Logic enhancement techniques are discussed, which seek to improve interchannel separations for the principal soundsource, at the expense of secondary sources. As an interim measure, a modified commercial logicenhanced (Variomatrix) decoder was studied, which led to the development of a purposebuilt logicenhanced decoder for Matrix H. The latter combines the virtues of both linear Matrix H decoding, and the variablematrix logic enhancement technique. All the decoders described are capable of providing a good surroundsound reproduction. In particular, a purposebuilt Matrix H logicenhanced decoder has been shown to exhibit a performance very close to a discrete 4channel system; the failings normally associated with logicenhanced decoders are almost inaudible.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 February 1977
 Bibcode:
 1977STIN...7722306G
 Keywords:

 Decoding;
 Logic Circuits;
 Matrices (Circuits);
 Discrimination;
 Linear Systems;
 Signal To Noise Ratios;
 Communications and Radar