| 摘要 |
At transmission (10) each bit for transmission is coded as a function of its state by producing (12) a particular coding frequency combination, these being divided into two distinct bands spaced one from another and the coding combinations being chosen such that frequencies ranked in the same sequence place in these combinations do not occupy the same frequency band. A signal comprising the coding combination is injected to the network (N,P) and at reception (20), is applied to demodulators (22, 23), each assigned to one respective frequency band, to be correlated with locally generated signals (25, 26) which reproduce the coding combinations with a constant frequency shift, the bit state being determined (24) as a function of the correlation output. |
