Radiotelephone system employing digitized speech/data and embedded signalling

Abstract

Abstract A radiotelephone system in which the signalling protocol for the system is embedded in the frame synchronization of the digital messages transmitted on the system. System state communication is achieved by utilizing a sequence of normal synchronization words and their ones complement inverses. Reliability of the coding is achieved by detecting normal or inverse words as binary levels when fewer than a predetermined number of bit errors exist in the bit sequence. If the predetermined number of bit errors is exceeded, a selected binary one or zero is subtituted (3003). This selected sequence of binary levels is decoded (3101) and the Hamming distance between a masked decoded sequence and a masked selected sequence is calculated (3207). If the Hamming distance calculation yields a number greater than the error correction capability of thge coding function, a new set of substituted binary levels is tried (3205), otherwise the decoded sequence is accepted as correct.

Inventors

• 👤 Stephen Norman Levine
• 👤 Albert J. Leitich

Bibliographic Details