Spread spectrum digital transmission system with low frequency pseudorandom coding of the useful information and method for spectrum spreading and compressing used in such a system.

摘要

System and method for combining, within a transmitter, each block of a digital signal to be transmitted with a sample originating from a pseudo-random generator operating at low frequency. The results of the various combinations are converted into orthogonal or quasi-orthogonal sequences, modulated and transmitted to the receiver. The receiver performs demodulation of the signal received and combines each sequence with a sample identical to that used for the low-frequency coding within the transmitter in order to reconstitute the various blocks. Makes it possible to carry out low-frequency spectral spreading of a signal to be transmitted. <IMAGE>