HIERARCHICAL TRANSMISSION SYSTEM AND TRANSMITTER-RECEIVER THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a hierarchical transmission system in which an interleave circuit is used in common and the distance of interleave is made longer as to a hierarchy small in multi-valued level. SOLUTION: When input data are 16QAM, data of 4-bit per one symbol are fed to a selection circuit 15 via a path B, where required data are selected, the selected data are de-interleaved for each symbol by a de-interleave circuit 52 and required processed-data are selected by a selection circuit 53 and fed to a forward error correction(FEC) decoder 54. When input data are quadrature phase shift keying(QPSK) data, data of 2-bit per symbol passes through a path A, latched partly in a latch circuit 56 via a switch 55 and outputted in pairs with an output at a side of a through-path 57. Each output of the through-path 57 and the latch circuit 56 is a 2-bit output and both data are 4-bit data (2-symbol) in total and fed to the selection circuit 51 and the data are processed afterward similarly to the case with the 16QAM data.