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:
Sep. 27, 1994
Filed:
Jul. 27, 1993
Osamu Kobayashi, Kawasaki, JP;
Kunihiko Gotoh, Kawasaki, JP;
Fujitsu Limited, Kanagawa, JP;
Abstract
A variable attenuator has a plurality of attenuation resistor units, a plurality of switching units, and a plurality of impedance compensation resistor units. The attenuation resistor units are connected in series for attenuating an input signal, and the switching units are provided for the attenuation resistor units. One of the switching units are selected in accordance with a digital control signal supplied from an external source. Each of the impedance compensation resistor units is connected in series with the respective switching units to compensate an output impedance to a specific value regardless of the state of the switching units. Therefore, the variable attenuator of the present invention can correctly control the level of an analog signal by a digital signal.