Synchronization Techniques for the Information Channel with Codec Based on Code Signal Feature

Synchronization of all constituent units must be provided in all digital data transmission systems (DDTS) with a serial synchronous interface, primarily of encoding and decoding devices. The paper investigates the DDTS which work under the influence of highly intensive noise. To provide the proper level of information reliability, it is suggested to use cascade coding with an error-correcting primary code (PC) and secondary code (SC) based on code signal feature (CSF). The paper shows the structure of the CSF-based code describes its code words properties and provides the encoding and decoding basics. To ensure synchronous and in-phase DDTS operation, both code cascades should be synchronized. It is shown, that common approach with synchronization pulses (SP) can be used in the PC. To transparently transmit the PC SP via communication channel, the SC code word set can be extended with a special code combination, which represents PC SP. The CSF-based SC is self-synchronized code; therefore it does not need special SP signal, which simplifies the codec implementation. The work provides structural schemas for the SC encoder and decoder, which take additional PC SP into account. The time diagrams for the sample PC code word transmission are also given.