| 摘要 |
In a coding device, a pseudo-ternary signal is derived from a binary data flow. Two of the three values of the latter signal represent the same data status. The three values of the pseudo-ternary signal determine the transition instant between the two values of the status quantity of the medium used. The transition instants are advanced and delayed, respectively, by said two values. The other signal value each time produces a nominal transition instant. A status transition then exists between every two successive bit cells. As a result of said mutual time shifts, a bipolar, phase-modulated signal with inserted pilot tone is generated. This signal, furthermore, does not contain a d.c. component and is suitable for saturation storage in a magnetic medium. The extraction of the data is realized by the formation of an exclusive-OR-function between the signal received and the output signal of a phase-locked loop which is cosynchronized by the signal received.
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