| 摘要 |
The present invention provides a novel Geometric Harmonic Modulation (GHM) method. The GHM method functions in two modes, a preamble mode and a traffic mode. During the preamble mode, n+1 frequencies are each offset by a predetermined phase in a transmit unit and passed through a channel to a receive unit. The set of phases is used as the spreading code in the transmit unit, and also acts as an 'address' of intended receive units. The receive unit monitors preamble signals to determine the phases. When it recognizes a set of phases, or 'address', which pertains to itself, the receive unit stores the phases and uses these phases to despread and decode the appended message. After the preamble mode is finished, the GHM modulator enters the traffic mode and requests the message to be transmitted from the message source. A traffic carrier waveform is created by multiplying tones, each having its specific phase. An analog or binary message is encoded by modulating the traffic carder waveform. The receive unit detects a preamble carrier and recovers the particular preamble phases to be used as the despreading 'key'. The receive unit then employs the phases in despreading the received signal to recover the transmitted binary message.
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