Apparatus and method for ultra narrow band communications
First Claim
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1. A method for transmitting digital data or audio data, comprising:
- modulating a carrier with the digital data or audio data;
abrupt phase shift keying the carrier and removing the unnecessary Fourier sidebands, the carrier bearing phase shift information required; and
filtering the modulated carrier using a narrow bandpass filter having essentially no group delay.
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Abstract
A method and apparatus for transmitting information combining abrupt phase change modulation with an ultra narrow band filter to remove unnecessary Fourier sidebands, resulting in a single frequency being transmitted to carry data. The method examines and detects the changes in the carrier phase only, after filtering to remove or reduce all sidebands, to obtain a usable signal. Only a single frequency with phase changes is transmitted. An ultra narrow band filter, having a rapid rise time and near zero group delay, passes the near instantaneous modulation changes of phase in the carrier.
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Citations
26 Claims
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1. A method for transmitting digital data or audio data, comprising:
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modulating a carrier with the digital data or audio data;
abrupt phase shift keying the carrier and removing the unnecessary Fourier sidebands, the carrier bearing phase shift information required; and
filtering the modulated carrier using a narrow bandpass filter having essentially no group delay. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 17)
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12. A circuit for abrupt phase shift keying a carrier, comprising:
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a phase change modulator adapted to abruptly change a phase of the carrier; and
an ultra narrow bandpass filter having a substantially zero group or envelope delay communicating with the phase change modulator to output a narrow bandpass filtered form of the abruptly phase changed carrier signal, wherein the ultra narrow bandpass filter and the phase change modulator in combination reduce a level of unnecessary Fourier sideband frequencies. - View Dependent Claims (13, 14, 15, 16, 18, 19, 20, 21)
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22. An apparatus for transmitting any rectangular waveform at radio frequency, comprising:
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a circuit for abrupt phase shift keying a carrier; and
a narrow bandpass filter having essentially no group delay for narrow bandpass filtering of transmitted signal. - View Dependent Claims (23, 24, 25, 26)
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Specification