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:
Oct. 11, 1994
Filed:
Aug. 31, 1993
Junichi Hasegawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
The invention provides a fading simulator method and a fading simulator by which the attenuation ratio is not varied and the fading characteristic of a wide band can be realized stably even when the notch frequency sweeps. A fading simulator is interposed between a transmitter and a receiver, and a signal from the transmitter is inputted to first and second path artificial circuits of the fading simulator. In the first path artificial circuit, the attenuation amount of a first variable attenuator is controlled to control the amplitude of the signal passing therethrough, and the signal is delayed by a first delay circuit. Meanwhile, in the second path artificial circuit, a variable phase shifter is controlled to control the phase of the signal passing therethrough, and the attenuation amount at a second variable attenuator is controlled in accordance with a signal obtained by addition of an amplitude characteristic leveling amplitude correction value to an amplitude control signal, whereafter the passing signal is delayed by a second delay circuit. The signals from the first and second path artificial circuits are composed by a composer, and the thus composed signal is inputted to the receiver.