In the domestic satellite medium video service generally enjoys the allocation of full transponder bandwidth. Such allocation can provide abundant spectrum space for in band, ancillary services.
Thoughtful use of the available spectrum and efficient modulation loading can yield dynamically increased information transfer with little more than statistical impairment to extant signals.
One such application provides for the enhancement of satellite delivered program audio into compatible non-redundant stereo.
The technique addressed is an adaptation of the sum and difference scheme introduced by Zenith - G.E. in 1961 and applied here to the conventions of satellite transmission into CATV systems.