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.

Date of Patent:
Oct. 03, 2000

Filed:

Mar. 05, 1999
Applicant:
Inventors:

Katsuya Shimomura, Kasugai, JP;

Shinji Saito, Kasugai, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03F / ;
U.S. Cl.
CPC ...
330254 ; 330134 ;
Abstract

A variable gain circuit amplifies an input signal with a gain which depends on a control voltage. The gain circuit has a first amplifier with a gain that is proportional to the control voltage in a relatively low region of the control voltage and a second amplifier with a gain that is proportional to the control voltage in a relatively high region of the control voltage. The second amplifier also includes a gain circuit which maintains the gain of the second amplifier constant in a relatively low range of the control voltage. The second amplifier is connected to the first amplifier via a pair of coupling capacitors. The variable gain circuit may be used in a transmitter of a CDMA telephone.


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