A “Hamming” Encoder/Decoder For Single Channel, 7.42-Unit, Teletype Systems

Abstract

The “Hamming” encoder/decoder is capable of detecting and correcting and single-bit error which may occur during the transmission of a data word. This report presents a detailed analysis of a “Hamming” encoder/decoder design to be used with a single-channel, 7.42-unit, teletype systems. Evaluation of a constructed prototype is included, along with a method used to induce single-bit errors to test the detection and correction capabilities of the system. Tests on the prototype were made at a teletype speed of approximately 100 words per minute and after one hour of operation the system detected and corrected all but two single-bit errors. Distortion checks were also made on the system by applying up to 20% marking and spacing bias to both encoder and decoder, resulting in an output distortion measurement of less that 1% switching bias. This system can provide up to 100%, error-free data transmission if it is utilized in a communication environment where only single-bit errors per data word is tolerated.