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. 25, 1995
Filed:
Aug. 26, 1993
Yoshiaki Kumagai, Kawasaki, JP;
Yoichi Endo, Kawasaki, JP;
Fujitsu Limited, Kanagawa, JP;
Abstract
A signal transmission device having ALC function includes a detection circuit for output level detection when used in a multi-carrier :system where the number of carriers changes. The signal transmission device further has a variable attenuator for controlling a level of a transmission signal. A transmission circuit is coupled to the output of the variable attenuator for modulating a local oscillation signal with the output of the variable attenuator and for generating a modulated output signal. The detection circuit is provided with the modulated output signal for generating a detection voltage. The detection circuit includes a diode having a square-law characteristic region. A reference voltage generating circuit receives an information signal indicative of the number of carriers for generating a reference voltage corresponding to the number of carriers. A first control circuit is provided, receiving the detecting voltage and the reference voltage, for generating and supplying, to the variable attenuator, a first control signal of a difference between the detection voltage and the reference voltage. A second control circuit is supplied with the information signal indicative of the number of carriers, for generating and supplying, to the detection circuit, a second control signal corresponding to the number of carriers, whereby the square-law characteristic region of the diode in the detection circuit is shifted responding to the second control signal.