The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 03, 2006
Filed:
Mar. 31, 2000
Takashi Asahara, Tokyo, JP;
Toshiharu Kojima, Tokyo, JP;
Takashi Asahara, Tokyo, JP;
Toshiharu Kojima, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
The demodulator of the invention includes a DSP. The DSP determines the distortion amount of the transmission channel based on known signals included in a radio receiving signal, and estimates the frequency of the direct wave based on the distortion amount. Furthermore, the DSP rotates the phase of the distortion amount based on the phase amount corresponding to the estimated frequency of the direct wave. Next, the DSP estimates the center frequency of the Doppler spread based on the distortion amount after the phase is rotated. Furthermore, the DSP synthesizes the phase amount corresponding to the estimated center frequency of the Doppler spread and the phase amount corresponding to the frequency of the direct wave to estimate the last frequency offset. Thereafter, the DSP eliminates frequency offset of the radio receiving signal based on the estimated frequency offset. Thereby, a sufficient frequency offset compensating range can be secured, and excellent BER characteristics can be realized.