| 摘要 |
A method and apparatus for transmitting intelligence over a carrier wave are provided in which a signal wave form is indirectly added to a carrier wave to produce a composite wave having a recognizable pattern of variations in intervals that are defined by preselected locations in the composite wave. The pattern of variations in intervals resulting from the addition of the signal wave form to the carrier wave represents at least a portion of the intelligence to be transmitted over the carrier wave. The variations in intervals defined by the preselected locations in the carrier wave are detected and the detected interval variations are converted into a signal which has a characteristic that is a function of the recognizable pattern of interval variations. In the preferred embodiment, the intelligence is transmitted over an electric power distribution network utilizing the alternating voltage thereon as the carrier wave. By indirectly adding the signal wave form to the carrier wave, a simplified modulation system and method is provided which can be adjusted to control the amplitude of the signal wave.
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