| 摘要 |
The device comes within the branch of digital transmission and refers more particularly to the problem of the recognition of a message coded in the "no return to zero" code, which is usually rhythmed by a given frequency. According to the invention, a phase-locked loop is provided for reconstituting the original rhythm from the message, and a phase shifter having an instantaneous action is additionally provided in that loop. The analysis of the reaction of the loop after that phase shift, by means of integrators, gives a statistical data information on the existence of a message. The invention applies more particularly to very noisy NRZ transmission lines.
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