出版社：The Institute of Image Information and Television Engineers
摘要：A lot of research has been done on digital terrestrial television systems using orthogonal frequency division multiplexing (OFDM). One of important points in achieving a robust system against noise and disturbance is an error-correcting code and its decoding technique. A punctured convolutional code with the constraint length of 7 has already been chosen as the inner error-correcting code of the European digital terrestrial TV system. This paper discusses the basic characteristics of the code when it is combined with QAM or DAPSK systems under additive white Gaussian noise (AWGN) channels. The bit error rates (BERs) of the hard and soft-decision methods for the QAM and DAPSK systems are compared. A few different types of soft-decision techniques in particular are numerically examined for the DAPSK systems. The results show that the punctured convolutional code attains the coding gains of 2-5 dB for the QAM systems at the BER of 2×10-4. However, in some cases, the code can only achieve very small or even negative gains for the DAPSK systems at the BER.
