Frame synchronization for QAM

摘要

PCT No. PCT/GB92/00563 Sec. 371 Date Sep. 28, 1993 Sec. 102(e) Date Dec. 1, 1993 PCT Filed Mar. 27, 1992 PCT Pub. No. WO92/17972 PCT Pub. Date Oct. 15, 1992Frame synchronization for data transmitted using quadrature amplitude modulation is achieved by providing that one symbol per frame is chosen from a larger signal point constellation than the remaining symbols. Thus, bits are assembled into groups of unequal size to control the mapping between the data and the signal points. Where constellations having a number of points not equal to a power of two, these may be coded in groups; or the data may be converted into a mixed-base number the bases of which correspond to the number of points in the respective constellations.