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:
Oct. 13, 2015
Filed:
Jan. 29, 2015
Icom Incorporated, Osaka, JP;
Kazunori Shibata, Osaka, JP;
ICOM Incorporated, Osaka, JP;
Abstract
Provided is a radio receiver using a modulation scheme such as FSK or QPSK in which a transmission and reception frequency shift appears as DC offset in a demodulated signal, capable of increasing noise immunity while suppressing deterioration in sensitivity. A high-speed pull-in processing unitthat performs offset correction by subtracting a correction value Adj_DC obtained from transmission and reception frequency deviation from the demodulated (detected) signal and a low-speed pull-in processing unitthat feedbacks a correction value Adj_local(t) obtained from an average value of the demodulated (detected) signal to a local oscillatorare used in combination. The correction value Adj_DC for the high-speed pull-in processing is reduced over time by subtracting a correction amount Adj_Del(t) from the correction value Adj_DC and the feedback is performed, so that, as a result, the correction value Adj_DC for the high-speed pull-in processing is given to the low-speed pull-in processing. Accordingly, it is possible to increase noise immunity while suppressing deterioration in sensitivity in which the received signal is cut by a band-limiting filter.