Design and implementation of a chaotic codec

In this paper, we propose a secure spread spectrum communication systems, using chaotic spreading sequences. The main advantages of such usage are the increased security of the messages and also the number of users in the system. The low dimension of the chaos, generated in Chua´s circuit suggests a low degree of randomness in the chaotic signal. A digital chaotic codec is then developed to increase the complexity of the chaotic digital signal. The later is based on the general structure of Penaud´s codec and Frey´s modified codec, associated with the technique of dead-beat chaos synchronisation developed by Angeli. Contrary to the others codec, the proposed one is suitable to pass-band modulation