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:
May. 30, 2006
Filed:
Aug. 02, 2001
Naruichi Yokogawa, Kashihara, JP;
Takeshi Nishino, Nara, JP;
Kazuo Noda, Yamatotakada, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A carrier detection circuit of the present invention detects groups of pulses having a carrier frequency by using a detector, and integrates, by an integrator, a time in which the groups are detected, so as to generate a carrier detection level. Therefore, a transistor is only requested to have responsibility with respect to a frequency of a base band component, but not to the carrier frequency. This ensures a margin with respect to a response of the transistor, while allowing a feeble current to be used as charging and discharging currents for the capacitor. In this way, even if a capacitor in use has such a small capacity that the capacitor can be incorporated in an integrated circuit, the detection of the carrier is performed accurately. Meanwhile, by further providing a level change-over circuit, which increases an output of the detector relative to a reference integral value during a time in which the carrier is detected, it is possible to reduce malfunction caused by a light noise having swelling, in case an infrared ray remote control is used.