28 – Digital transmission

Publisher Summary Information from a data source is processed so that it can be reliably transmitted via a communication channel to a distant data terminal. The user will measure reliability in terms of the difference between the transmitted data and the received data. The processing tasks in the transmitting terminal fall into two categories. (1) Source coding is concerned with the structure and statistics of the data source; it will involve the conversion of the data into a more suitable form for subsequent processing and (2) channel coding is concerned with the characteristics of the transmission channel; it must ensure that the processed data is compatible with the requirements of the channel. Transmission errors are usually the most significant impairment to be found in a digital communication system. They are also difficult to predict and, therefore, difficult to quantify.