| 摘要 |
PROBLEM TO BE SOLVED: To realize a decoding technology by hard discrimination such as phase shift keying PSK or quadrature amplitude modulation QAM or the like (or soft discrimination by Viterbi decoding or trellis decoding or the like). SOLUTION: A demodulator-bit synchronization device 20 demodulates and synchronizes a PSK or QAM signal, generates an in-phase component I and a quadrature component Q and gives them to a discrimination circuit 24 and a microprocessor 22. The discrimination circuit 24 discriminates each distance of constellation points of a received signal with respect to a reference discrimination border, adjusts and optimizes the discrimination border on the basis of the distance and stores the optimized discrimination border to a discrimination map 26 of the discrimination circuit 24. The microprocessor 22 decodes the signal on the basis of the optimized discrimination border. Thus, a bit error rate BER can be enhanced without adopting a nonlinear reverse distortion technology for a transmitter, the weight of the transmitter is made smaller, and this technology is especially useful for applications such as a satellite communication system where a transmitter is installed on a satellite. |
