Computer Evaluation of Error-correcting Codes for PCM Telemetry

Communication in a broad sense is simply transferring information of some sort from one point to another, usually by means of electrical signals. The sender and the receiver of the information may be either man or machine. If the information to be transferred is in a numerical form, the system is called a Digital Data Communication System. This type of system is usually employed in machine-to-machine communication, but may be applied to transferring other types of information by first converting that information into a numerical (digital) form. In today\u27s typical Digital Data Communications, the numerical data is converted to binary data. This scheme greatly reduces the complexity of the equipment that is needed to transmit and receive, and also makes the receiving problem simpler because there are only two types of signals that are sent. The two signals are made as unlike as possible within the constraints of the system, and thus the receiver is less likely to become confused in deciding which one was sent. The disadvantage of binary signaling is that it takes a group of binary digits (bits) to represent each decimal digit and therefore we may have to send four or more times as many signals in a given time interval to maintain the same data rate. This disadvantage is more than offset by the simplicity of the equipment and greater accuracy