tailieunhanh - Lecture Digital communication systems - Lecture 4

Chapter 4 presents the following content: Eight milestones in human communication, language, writing, printing, telegraph and telephone, photography and motion pictures, radio and television, digital media, wireless handheld media, concluding observations. | DIGITAL COMMUNICATION SUSTEMS Fall 2012 Lecture 4 Linear block codes Rectangular codes Hamming codes Fall 2012 Lecture 4 Slide 1 Single Link Communication Model End-host Original source computers Receiving app user jr o V Digitize if needed Source binary digits message bits Source coding 1 Render display etc. Source decoding Bit stream Bit stream Channel Mapper Recv Coding Bits Signals samples Bits bit error Xmit Voltages correction samples over Demapper physical link Channel Decoding reducing or removing bit errors Fall 2012 Lecture 4 Slide 2 Embedding for Structural Separation Encode so that the codewords are far enough from each other Likely error patterns shouldn t transform one codeword to another single-bit error may cause 00 to be 10 or 01 0 Fall 2012 u0 01 10 001 1 Code nodes chosen in hypercube mapping of message bits to nodes If we choose 2k out of 2n nodes it means we can map all k-bit message strings in a space of n-bit codewords. The code rate is k n. Lecture 4 Slide