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. 03, 1999
Filed:
Jul. 11, 1997
Yasuhiro Kaneko, Saitama, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a portable telephone, a voice filter is connected to an antenna through a receiving circuit. A filter is connected to the voice filter through a switching circuit and filters the voice signal from the voice filter to produce a filtered voice signal. The filter has a first cut-off frequency when the filter is supplied with a first clock signal. The filter has a second cut-off frequency smaller than the first cut-off frequency when the filter is supplied with a second clock signal. A telephone receiver is connected to the filter through an amplifier. A clock generating circuit is connected to the filter and generates the first clock signal when is supplied with a first frequency control signal. The clock generating circuit generates the second clock signal when is supplied with a second frequency control signal. A control circuit supplies the first frequency control signal to the clock generating circuit when a receiving field intensity from the receiving circuit is greater than a first predetermined field intensity. The control circuit supplies the second frequency control signal to the clock generating circuit when the receiving field intensity is between the first predetermined field intensity and a second predetermined field intensity smaller than the first predetermined field intensity. The control circuit supplies a switch control signal to the switching circuit when the receiving field intensity is smaller than the second predetermined field intensity. The switching circuit is off when is supplied with the switch control signal.