US 7,321,639 B2 | ||
Demodulator and address information extractor | ||
Akira Yamamoto, Takatsuki (Japan) | ||
Assigned to Matsushita Electric Industrial Co., Ltd., Osaka (Japan) | ||
Appl. No. 10/513,149 PCT Filed Jan. 26, 2004, PCT No. PCT/JP2004/000635 § 371(c)(1), (2), (4) Date Nov. 02, 2004, PCT Pub. No. WO2004/079738, PCT Pub. Date Sep. 16, 2004. |
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Claims priority of application No. 2003-061429 (JP), filed on Mar. 07, 2003. | ||
Prior Publication US 2005/0169404 A1, Aug. 04, 2005 | ||
Int. Cl. H03D 3/22 (2006.01) |
U.S. Cl. 375—329 [369/44.13; 375/316] | 12 Claims |
1. A demodulator comprising:
carrier information extraction means for extracting carrier information from a BPSK modulated signal;
carrier generation means for generating a carrier based on the carrier information extracted by the carrier information extraction
means;
analog-to-digital conversion means for converting the BPSK modulated signal to a digital value;
multiplication means for multiplying the carrier output from the carrier generation means by the BPSK modulated signal digitized
by the analog-to-digital conversion means;
carrier period integration means for integrating a result of the multiplication performed by the multiplication means, with
respect to a period of the carrier generated by the carrier generation means; and
discrimination means for binarizing a result of the integration performed by the carrier period integration means,
wherein at least one of the carrier information extraction means and the carrier generation means is composed of a digital
circuit, and
the carrier generation means generates, as the carrier, a modified square wave, in which if the amplitude of the modified
square wave is 1 during the period of time in which the phase thereof is from 0 to π/3, the amplitude becomes 2 during the
period of time in which the phase is from π/3 to 2π/3, the amplitude becomes 1 during the period of time in which the phase
is from 2π/3 to π, the amplitude becomes −1 during the period of time in which the phase is from π to 4π/3, the amplitude
becomes −2 during the period of time in which the phase is from 4π/3 to 5π/3, and the amplitude becomes −1 during the period
of time in which the phase is from 5π/3 to 2π.
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