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:
Apr. 10, 2007
Filed:
Oct. 23, 2002
Yoshikazu Shimada, Kyoto, JP;
Hiroyuki Ashida, Kyoto, JP;
Yoshikazu Shimada, Kyoto, JP;
Hiroyuki Ashida, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A conventional receiver system has a filter circuit with unsatisfactory gain characteristics, and thus does not offer satisfactory reception performance. A receiver system of the invention has a filter circuit employing an equivalent inductor circuit including a capacitor, a gyrator composed of a plurality of operational transconductance amplifiers and having the capacitor as a load, and a resistor connected in series with the capacitor. A conventional receiver system has a band-pass filter circuit with a low third-order input intercept point, and thus does not offer satisfactory reception performance. The receiver system of the invention has, in the stage following a mixer, a band-pass filter circuit composed of a low-pass filter and a band-pass filter receiving the output signal of the low-pass filter, wherein the value obtained by dividing the higher cutoff frequency of the band-pass filter by the lower cutoff frequency thereof is smaller than 2, the center frequency of the band-pass filter is within a range of from about 1 to 3 MHz, and the cutoff frequency of the low-pass filter is higher than the center frequency of the band-pass filter.