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:
Aug. 11, 1998
Filed:
Oct. 16, 1996
Mikio Fukushi, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A demodulator for radio data communications is provided, which is capable of an optimum demodulation operation in response to the environmental condition under which communications are made independent of the preamble length. A phase angle calculator calculates a phase angle of the input signal. A frequency offset calculator calculates an offset of a carrier frequency of the input signal. A PLL generates a compensated phase angle of the input signal to compensate the frequency offset. A first detector detects the input signal using the uncompensated phase angle to generate a first detected signal. A second detector detects the input signal using the compensated phase angle to generate a second detected signal. A first phase distortion calculator calculates a phase distortion of the first detected signal. A second phase distortion calculator calculates a phase distortion of the second detected signal. A phase distortion comparator compares the phase distortions of the first and second detected signals to generate a result signal. A selector selects an output from one of the first and second detectors according to the result signal.