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AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsGenichiro Ota, Kazunori Inogai
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First and second quadrature modulators 109, 110 carry out quadrature modulation on Nyquist signals given a delay difference corresponding to 2/4 of their respective symbol periods using a cosine wave having a frequency corresponding to an odd-number multiple of the basic frequency of each Nyquist signal as a carrier. Third quadrature modulator 113 carries out quadrature modulation on the modulated signal obtained from first quadrature modulator 109 and the modulated signal obtained from second quadrature modulator 110 using a carrier having a predetermined frequency. Thus, it is possible to obtain modulated signals with four Nyquist signals allocated in a 1-symbol period T without any interference with one another.
1-13. (canceled)
A modulation method of applying quadrature modulation to a first input symbol and a second input symbol, comprising a quadrature modulation step of applying quadrature modulation to a Nyquist signal of said first input symbol and a Nyquist signal of said second input symbol obtained by giving a delay difference corresponding to an integer multiple of ¼ of the symbol period of said first input symbol to the Nyquist signal of said first input symbol using a cosine wave having a frequency corresponding to an odd-number multiple of the basic frequency of each said Nyquist signal as a carrier.
A modulation apparatus comprising a quadrature modulator that inputs a first Nyquist signal of a first input symbol and a second Nyquist signal of a second input symbol having a delay difference corresponding to an integer multiple of ¼ of the first input symbol period with respect to the Nyquist signal of said first input symbol and carries out quadrature modulation on the first and second Nyquist signals using a cosine wave having a frequency corresponding to an odd-number multiple of the basic frequency of each Nyquist signal.
A demodulation apparatus comprising a quadrature demodulator that carries out quadrature demodulation on a modulated signal obtained by carrying out quadrature modulation on first and second Nyquist signals using a cosine wave having a frequency corresponding to an odd-number multiple of the basic frequency of each said Nyquist signal.
Dependencies are inferred from the claim text.