Direct sequence spread spectrum data transmission.

摘要

In accordance with the invention, on transmission, the data are coded by a "transition" coding of differential type and drive a multiplexer which, for each data bit, selects a pseudo-random sequence at high throughput or the same sequence shifted by one code clock period according to the value of the data bit; on reception, the received signal is correlated with a pseudo-random code identical to that produced on transmission and synchronised to the received signal. The synchronisation error signal is measured, and error pulses are detected every time the pseudo-random sequence selected on transmission changes. With the changes in pseudo-random sequence corresponding to changes of state of the transmitted information, this transmitted information is reconstituted by comparison of the error pulses with two threshold levels, respectively positive and negative, followed by differential demodulation.