Multi-phase and multi-amplitude level modulator and modulation and demodulation methods
AssigneeRixon, Inc.
InventorRichard L. Stuart
Life of this patent
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Abstract
A multi-phase, multi-amplitude level modulation method, and modulator, is provided which produces a three-level, ten-phase modulated carrier. The carrier is modulated in three amplitude levels, viz., off, intermediate and high and in ten phase positions, to produce sixteen signal states, one state corresponding to the carrier being off, five intermediate amplitude level states having five equally spaced phase positions, and ten high amplitude level states having ten equally spaced phase positions. A number of different four digit binary coding schemes for the sixteen signal states are disclosed together with other different coding and modulation techniques.
Claims32
A multi-phase, multi-amplitude level modulation method comprising generating a carrier signal, generating a modulating signal having first, second and third amplitude levels and ten phases, and modulating said carrier with said first, second and third amplitude levels and ten phases to produce sixteen signal states, said first level corresponding to carrier off operation and providing a first signal state, said second level comprising an intermediate level and said carrier being modulated at five equally spaced phases for said second level to provide five of said sixteen signal states, and said third level comprising an amplitude level which is substantially higher than said intermediate level and said carrier being modulated at ten equally spaced phases for said third level to provide ten of said sixteen signal states, alternate/equally spaced phases of said third level being in phase with respective phases of the five phases of the second level.
A multi-phase, multi-amplitude level modulator comprising means for generating a carrier, means for generating a modulating signal having first, second and third amplitude levels and 10 phases, and means for modulating said carrier with said first, second and third amplitude levels and ten phases to produce sixteen signal states, said first level corresponding to carrier off operation and providing a first signal state, said second level comprising an intermediate level and said carrier being modulated at five equally spaced phases for said second level to provide five of said 16 signal states, and said third level comprising an amplitude level which is substantially higher than said intermediate level and said carrier being modulated at ten equally spaced phases for said third level to provide 10 of said 16 signal states, alternate equally spaced phases of said third level being in phase with respective phases of the five phases of the second level.
A modulator as claimed in claim 23 wherein said encoder provides coding which is the inverse of that of claim 31, whereby each "1" is changed to "0" and each "0" is changed to "1".
A demodulation method for demodulating an amplitude-phase modulated signal having 16 states comprising a zero level or carrier off state, five intermediate level states and ten high level states, said method comprising the steps of demodulating the 16 states of the amplitude-phase modulated signal by coherently demodulating the signal for the five intermediate level states by comparing the phase of the signal with a reference signal, differentially demodulating the signal for the ten high level states by comparing the phase of the signal with that of the previous state and phase comparing the phase of the signal with that of the previous state for the zero level or carrier off state and amplitude demodulating the signal to determine the signal level and the type of demodulation.
Dependencies are inferred from the claim text.