Method and device for coding and decoding a broadband transmission

摘要

In a method of coding and decoding a broadband transmission of the spread spectrum type, the signal to be transmitted is encoded by modulation in accordance with a code consisting of a pseudo-random binary sequence of period T composed of two alternating half-sequences of period T/2 and having virtually nil cross-correlation. In the receiver a reception code is generated which is the same as the transmission code except that one of the half-sequences of the reception code is shifted in a circular rotational sense relative to the corresponding half-sequence of the transmission code. This reception code enables synchronization of the transmission and reception code generators by correlation of the reception code with the received coded signal using only one correlator, and is also used to control a demodulator for decoding the received signal.