| 摘要 |
PROBLEM TO BE SOLVED: To enhance the coding gain in the case of coding communication data. SOLUTION: A modem of a central station includes a least significant bit convolution coding system. A transmitter side of the modem includes an encoder, where convolution coders 35I, 35Q respectively encode one bit (preferably, the least significant bit) of each symbol supplied to a phase and amplitude modulation constellation. Thus, the coded bit selects any of a plurality of sub constellations of a modulation signal. The coders 35I, 35Q are respectively configured as a 32 and a 64-state finite state machines. A minimum Humming distance given by a code is '4'. Thus, a coding gain of the modem can be enhanced compared with that of a conventional convolution coding system. |
