TRANSMITTER, RECEIVER AND TRANSMISSION DEVICE

摘要

PROBLEM TO BE SOLVED: To attain both NTSC and HDTV broadcasts in the satellite broadcasting by setting individually the error correction capabilities for the error correction coding processes which are applied to the 1st and 2nd data strings at the error correction coding parts. SOLUTION: The error correction coding parts 871a and 871b set individually the error correction capabilities for the error correction coding processes which are applied to the 1st and 2nd data strings. A modulator 4 shifts the signal points to other points set on a space diagram so as to set the minimum distance at (2δ×S) between both adjacent points. Then m pieces of signal points can be discriminated from each other by a 1st threshold group which divides the space diagram into m pieces of areas, and n pieces of signal groups can be discriminated from each other by a 2nd rough threshold group which divides the space diagram into n pieces of areas. The signals sent from a transmission part 5 include the information on the placement of m pieces of signal points set on the space diagram, and this information includes the information which is needed for deciding the number m of signal points. In this example, 2δshows the minimum distance set between both adjacent signals and S shows a variable shift extent (S>=1).