Introduction Many info signals are naturally in the forms of sequence,such as 1.A digital picture in JPEG file; 2.A video file in H.264 format; 3. A music file in MP3 format; 4.An email However,there are also many analog msgs, Analog msgs are often converted to digital form to take the advantages of digital transmission. PCM is a typical technique of this process. UESTC-Digital transmission through the AWGN channel Prof李晓峰 6