| 摘要 |
PURPOSE:To improve the word error rate characteristic by applying trellis decoding by a specific logarithmic likelihood obtained from a reception electric field level at the point of time of decoding in the unit of bits. CONSTITUTION:A detection output 3 from a receiver 2 is outputted to a CPU 10 as a decoded output 5 in the unit of bits via a decoding circuit 4 in the unit of bits. A reception electric field level output 7 is obtained by an amplitude detector in the receiver 2. The reception electric field at a point of time of bit discrimination is sampled synchronously with an discrimination timing pulse 6 of the decoding in the unit of bits, the output 9 of A/D conversion converted by an A/D converter 8 is extracted and the logarithmic likelihood ratio in equation I is calculated by the CPU 10. The output 5 and the output 9 at the point of time are extracted in the CPU 10 and the decoding is executed one by one step to output the decoding output 13 by using a program for decoding stored in the ROM 11. Thus, the word error rate characteristic is improved. In equation, Pe is a bit error rate determined from the received electric field.
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