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:
Aug. 26, 1997
Filed:
Oct. 18, 1995
Norihiro Mochizuki, Machida, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A demodulation apparatus and a communication system using the same are disclosed. The apparatus comprises code generation means for generating a reference spread code corresponding to a first signal modulated by a spread code, and an elastic surface wave element for receiving the first signal and a second signal output from the code generation means, and outputting a demodulated information signal. The elastic surface wave element comprises a piezoelectric substrate, a first excitation electrode, formed on the piezoelectric substrate, for generating a first elastic surface wave which propagates in a predetermined direction in accordance with the first signal, a second excitation electrode, formed on the piezoelectric substrate, for generating a second elastic surface wave which propagates in a direction opposite to the predetermined direction in accordance with the second signal, and an acousto-electric converter, formed between the first and second excitation electrodes on the piezoelectric substrate, for outputting a convolution signal of the first and second signals on the basis of the first and second elastic surface waves, wherein the acousto-electric converter selectively converts an elastic surface wave having a wave number twice a wave number of the first and second elastic surface waves into an electrical signal.