ABSTRACT

The transmission of information over a communication system always results in some degradation in the quality ofthe information. In digital links, degradation cjf the information content of a signal is measured in terms ofthe bit error rated A fundamental difference between analog and digital signals is that we can increase the bit error rate of a digital signal by the use of errorcorrection techniques. No such techniques is available for analog signals since once the information is contaminated by noise, it is extremely difficult to remove the npise, as we cannot in general distinguish between the signal and the noise electronically. In a digital system, we can add extra redundancy bits to our data stream, which can tell us when an error occurs in the data and can also point to the particular bit or bits that have been corrupted. Coding theory refers to error-detection or correction. This implies that additional (redundant) to the data stream to form error-detecting or error correcting codes. Finally, the decoder (receiver) works with various decoding techniques using Abstract Algebra to be able to detect and correct errors in a given data stream. These} techniques are software implemented and are basically algorithms.