摘要 |
A digital message transmission system has a transmit side wherein two pulse sequences are sampled at the rate of two plesiochronic data clocks and the sampled sequences are expanded by the insertion of additional information in the manner of "positive stuffing." The two pulse sequences including the additional information are transmitted to the receive side in a pulse frame, the procedure being reversed at the proceed side to decode the message. The momentary phase relationship between the two plesiochronic data clocks, in the form of a binary phase word, is inserted as a portion of the additional information. An auxiliary clock signal is derived from a reference data clock signal for use in transforming the phase measurement (difference between a higher and a lower frequency level) into the binary phase word. An auxiliary plesiochronic clock signal, which is plesiochronic relative to the auxiliary clock signal, is derived from the reference data clock signal and the plesiochronic data clock signal (plesiochronic relative to the data clock signal), the auxiliary plesiochronic clock signal being compared in phase to the auxiliary clock signal.
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