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:
Jul. 15, 1997
Filed:
Jun. 05, 1995
Junichi Somei, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
There is provided a switching circuit of a BS converter capable of assuring a high sensitivity. A BS tuner superimposes a band switching pulse signal on a power voltage when selecting a high band, and supplies the resulting signal to a BS converter. The BS converter amplifies a pulse signal selected by a filter circuit of a switching circuit by ten times in a differential amplifier, rectifies the resulting signal in a rectifying circuit, and compares the resulting signal with a reference voltage in a comparator circuit, thereby detecting the presence or absence of the band switching pulse signal. When the band switching pulse signal is detected, a high-band local oscillator is turned on by a drive circuit. When the signal is not detected, a low-band local oscillator is turned on. Thus, by amplifying by about ten times the band switching pulse signal having a voltage of about 0.6 V, a reception frequency band is switchedly selected with high accuracy.