MODULATION DEVICE AND DEMODULATION DEVICE
First Claim
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1. A modulation device, comprising:
- a first spread code generation unit which is configured to generate a first spread code having a predetermined cycle;
an audio signal input unit to which an audio signal is input;
a first modulation unit which is configured to phase-modulate the first spread code in each cycle on the basis of data code; and
a combining unit which is configured to combine the audio signal with a modulation signal which has been generated on the basis of the phase-modulated first spread code and distributed in a frequency range higher than a predetermined frequency to output a combined signal.
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Abstract
A modulation device includes: a spread code generation unit which generates a spread code having a predetermined cycle; an audio signal input unit to which an audio signal is input; a first modulation unit which phase-modulates the spread code in each cycle on the basis of a data code; and a combining unit which combines the audio signal with a modulation signal which has been generated on the basis of the phase-modulated spread code and distributed in a frequency range higher than a predetermined frequency to output a combined signal.
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Citations
18 Claims
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1. A modulation device, comprising:
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a first spread code generation unit which is configured to generate a first spread code having a predetermined cycle; an audio signal input unit to which an audio signal is input; a first modulation unit which is configured to phase-modulate the first spread code in each cycle on the basis of data code; and a combining unit which is configured to combine the audio signal with a modulation signal which has been generated on the basis of the phase-modulated first spread code and distributed in a frequency range higher than a predetermined frequency to output a combined signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A demodulation device, comprising:
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an audio signal input unit to which a combined signal is input, the combined signal being obtained by combining an audio signal with a modulation signal, which has been generated on the basis of a first spread code having a cycle phase-modulated in each cycle on the basis of a data code and has been distributed in a frequency range higher than a predetermined frequency; a high-pass filter which is configured to cut off a frequency component equal to or lower than a cutoff frequency of the combined signal to extract a component of the modulation signal; and a code determination unit which is configured to decode the data code combined in the audio signal on the basis of an analysis result of the extracted component of the modulation signal. - View Dependent Claims (11, 12, 15, 16)
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13. A demodulation device, comprising:
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an audio signal input unit to which an audio signal is input, the audio signal being obtained by combining a plurality of spread codes, which are synchronized with each other and have different code sequences; a mode determination unit which is configured to determine a mode from a reference mode in which a spread code separated from the input audio signal includes a reference spread code, which is not phase-modulated by a data code, and a parallel mode in which the spread code excludes the reference spread code; a first demodulation unit which is configured to operate in the parallel mode; and a second demodulation unit which is configured to operate in the reference mode, wherein the first demodulation unit detects respective correlation values of the audio signal with respect to the plurality of spread codes, and demodulates the data code on the basis of the peak of each of the correlation values, and the second demodulation unit includes; a first correlation detection unit which is configured to detect a first correlation value, which is a correlation value of the audio signal with respect to a spread code phase-modulated by the data code; a second correlation detection unit which is configured to detect a second correlation value, which is a correlation value of the audio signal with respect to the reference spread code; an addition unit which is configured to add the first correlation value and the second correlation value to output a combined correlation value; a peak detection unit which is configured to detect a peak value of the combined correlation value in each cycle of the spread code phase-modulated by the data code; and a code determination unit which is configured to decode the data code combined in the audio signal on the basis of the magnitude of the peak value detected by the peak value detection unit. - View Dependent Claims (14, 17, 18)
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Specification