Method and apparatus for signal modulation and detection
First Claim
1. A method of receiving a signal wave occupying a predetermined bandwidth that imparts to it a digital modulation whose level depends on the direction of arrival of the signal wavefront, and which as a result creates a digitally modulated component signal embodying energy diverted from the arriving signal to a more widely spread spectrum, and hence reduces the signal spectral density within said predetermined bandwidth, the fraction of the total arriving signal energy so diverted being dependent on the direction of arrival of the signal wavefront, comprising the steps of:
- providing a set of different positions in space for intercepting an arriving signal wavefront;
controlling the time of the reception from each of said different positions to abruptly hop among said positions, which in effect times the introduction into the received signal of an abrupt direction-dependent shift;
adjusting the separation between successively hopped positions of signal wavefront interception; and
adjusting the orientation of the line segment between successively hopped positions of signal wavefront interception.
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Accused Products
Abstract
The disclosure relates to methods and apparatus for separating radio signals arriving from different directions and for multiplexing signals intended for receivers dispersed in different directions. The methods and apparatus employ a plurality of antennas with spacing and individual feedline characteristics designed so that a modulation is imparted to each of a plurality of incident signals, for receiving antennas, and radiated signals for transmitting antennas, the modulation level of each signal being determined by the direction of propagation of the signal and by the spacing between antenna pairs. Accordingly, the orientation of lines connecting pairs of antennas as well as the spacing between antennas are set to inhibit the modulation in a particular direction, or to strip a particular modulation off a signal incident from a selected direction.
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Citations
33 Claims
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1. A method of receiving a signal wave occupying a predetermined bandwidth that imparts to it a digital modulation whose level depends on the direction of arrival of the signal wavefront, and which as a result creates a digitally modulated component signal embodying energy diverted from the arriving signal to a more widely spread spectrum, and hence reduces the signal spectral density within said predetermined bandwidth, the fraction of the total arriving signal energy so diverted being dependent on the direction of arrival of the signal wavefront, comprising the steps of:
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providing a set of different positions in space for intercepting an arriving signal wavefront; controlling the time of the reception from each of said different positions to abruptly hop among said positions, which in effect times the introduction into the received signal of an abrupt direction-dependent shift; adjusting the separation between successively hopped positions of signal wavefront interception; and adjusting the orientation of the line segment between successively hopped positions of signal wavefront interception. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for receiving signal waves of generally the same frequency within a predetermined bandwidth, incident from a plurality of different directions, and for rejecting signal power/energy incident from all but one desired direction, comprising:
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antenna means having a set of different positions in space for intercepting signal wavefronts incident from a plurality of different radial directions; means for controlling the time of the reception from each of said different positions to abruptly hop among said positions, which in effect times the introduction into the received signal of an abrupt direction-dependent shift; means for adjusting the separation between successively hopped positions and the orientation of the connecting line segment between said successively hopped positions; and means for selecting signal waves from a desired direction, occupying said predetermined bandwidth, nonresponsive to signal waves arriving from other than said desired direction. - View Dependent Claims (13)
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14. A method of radiating a signal wave originated within a predetermined bandwidth that imparts to it a digital modulation whose level is direction-dependent and which as a result creates a digitally stepped-phase-modulated component signal wave representing a diversion of a direction-dependent fraction of the radiated power/energy to a more widely spread spectrum and hence reduced spectral density within said predetermined bandwidth, comprising the steps of:
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providing a set of different positions for effecting radiation; controlling the time of the radiation from each of said different positions, thereby introducing abrupt direction dependent shifts in the radiated signal from one of said positions to another; and adjusting the separation and orientation of the connecting line segment between pairs of positions. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An apparatus for radiating signal waves of generally the same frequency intending each of said signal waves to be received along a separate direction of a propagation ray path with negligible interference from the other signal waves, comprising:
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antenna means having a set of different positions for effecting radiation; means for causing at least one signal wave to be radiated from a combination of unhopped antenna positions, the combination being adjusted to null out said signal wave in selected directions; means for causing signals other than said signal to be each radiated from only one antenna position at a time; means for abruptly hopping the position of the point of radiation of each of said other signals between a pair of spaced antennas assigned to it, thereby introducing direction-dependent phase jumps in the radiated signals; means for adjusting the separation and connecting line orientation between each pair of antennas assigned to each of said other signals so that corresponding said other signal power/energy is entirely spread out in frequency spectrum when observed along the radial direction intended for said signal radiated from a combination of unhopped antenna positions; means for code modulating said other signals by antenna hopping with negligibly correlated codes to limit mutual interference among them in distant receivers.
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25. In a communication system wherein signal waves of generally the same frequency occupying a preassigned bandwidth are provided to a plurality of transmitters, each having a signal wave radiating position, and wherein the signal waves are transmitted from the transmitters to a receiver, having a signal wave receiving position, the improvement comprising:
means for suppressing interference between signal waves transmitted by the plurality of transmitters including; means for repetitively hopping between at least two of said radiating and/or said receiving positions, thereby imparting direction-dependent phase-jump modulation on the received signal waves; and means for rejecting power/energy of signal waves from all but one of the plurality of transmitters responsive to the imparted direction-dependent phase-jump modulation of the signal waves.
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26. In a system wherein signal waves are radiated from at least one radiating position and the signal waves are received at a receiving position from a plurality of different directions, a method of reducing interference by reducing received power/energy of signal waves from all but one of the plurality of directions comprising the steps of:
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repetitively hopping, among at least two spaced points, the position of at least one of said radiating and receiving positions according to a predetermined switching code/sequence thereby imparting direction-dependent phase-jump modulation in the received signal waves; and reducing by filter means received power/energy of signal waves from all but one of the plurality of directions based on dispersal in frequency spectrum of the power/energy of said signal waves resulting from the imparted direction-dependent phase-jump modulation thereof. - View Dependent Claims (27, 28, 29, 30, 31)
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32. A method for selecting signal waves originating within a predetermined bandwidth and arriving from a particular direction comprising the steps of:
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providing at least one position for radiating signal waves; providing at least one position for receiving the signal waves; abruptly hopping one of said radiating and receiving positions among a set of spaced positions thereby imparting direction-dependent phase-jump modulation in the signal waves; and selecting signal waves from the desired direction within said predetermined bandwidth responsive to the imposed direction-dependent phase-jump modulation of the signal waves. - View Dependent Claims (33)
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Specification