US 6,983,134 B1 | ||
Method and apparatus for automatic frequency control and demodulator | ||
Takashi Asahara, Tokyo (Japan); and Toshiharu Kojima, Tokyo (Japan) | ||
Assigned to Mitsubishi Denki Kabushiki Kaisha, Tokyo (Japan) | ||
Appl. No. 9/926,556 PCT Filed Mar. 31, 2000, PCT No. PCT/JP00/02123 § 371(c)(1), (2), (4) Date Nov. 19, 2001, PCT Pub. No. WO01/76097, PCT Pub. Date Oct. 11, 2001. |
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Int. Cl. H04B 1/18 (2006.01) |
U.S. Cl. 455—182.2 | 14 Claims |
1. An automatic frequency control method for controlling the frequency of a radio receiving signal by compensating a frequency
offset of the radio receiving signal, said radio receiving signal periodically including a plurality of adjacent known signals,
comprising:
estimating a frequency of a direct wave of the radio receiving signal and a center frequency of a Doppler spread of the radio
receiving signal based on distortion amounts of the adjacent known signals included in the radio receiving signal, and
compensating the frequency offset of the radio receiving signal based on both of said frequency of a direct wave and said
center frequency of a Doppler spread.
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