The use of digital signal processors in underwater communication systems

The current generation of underwater telemetry systems tend to use proven low data rate `discrete-component´ designs. These systems perform well under static conditions, but their performance rapidly degenerates when the environment in which they are used becomes more dynamic. The next generation of underwater telemetry systems will be adaptive and combat dynamic effects by processing signals using complex detection algorithms. The next step in the evolution of underwater communication systems is the development of systems that adapt automatically to changes in the environment and execute algorithms in real time which will encode, detect and decode transmitted signals more efficiently. This paper presents a DSP-based underwater communication system that uses four `Analogue Devices´ digital signal processors to control the transmission, modulation and demodulation of data from a sea-bottom unit to a surface receiver. The system uses multiphase 2, 4 or 8 differential phase shift keying (DPSK) and can be viewed as the first stage in the development of an adaptive underwater system that will more effectively combat the effects of the dynamic underwater environment