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:
Sep. 07, 1999
Filed:
Sep. 12, 1997
Teruo Sasaki, Tokyo, JP;
Nec Corporation, Tokyo, JP;
Abstract
A multivalued FSK demodulation window comparator includes an MSB comparator, an LSB comparator, a reception electric field strength detector, and a reference voltage generating circuit. The MSB comparator determines at least the polarity of a frequency shift of a radio frequency. The LSB comparator determines the absolute value of the frequency shift of the radio frequency. The reception electric field strength detector detects the strength of a radio signal and outputs a signal corresponding to the detected strength. The reference voltage generating circuit changes the reference voltages of the LSB comparator in accordance with an output voltage from the reception electric field strength detector. When the output voltage from the reception electric field strength detector is not higher than a predetermined level, a reference voltage from the reference voltage generating circuit changes.