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:
Jun. 20, 2000
Filed:
Aug. 07, 1997
Masatoshi Ohtsuka, Fukuoka, JP;
Naoki Koga, Fukuoka-ken, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A spread spectrum communication apparatus employs a surface acoustic wave matched filter and surface acoustic wave delay lines which enables the demodulation in accordance with the QPSK scheme. A SS demodulator has a correlated signal acquisition circuit for demodulating a received SS signal to acquire a correlated signal, first and second delay circuits for delaying an output signal from the correlated signal acquisition circuit, and first and second adder circuits for adding the output signal of the correlated signal acquisition circuit and respective outputs of the first and second delay circuits. The first delay circuit delays the input signal by T+(.+-.n+5.times.a/8)/fc, while the second delay circuit delays the input signal by T+(.+-.m-5.times.a/8)/fc. Thereby, a spread spectrum communication apparatus which enables the demodulation in accordance with the QPSK scheme by a simple configuration using a surface acoustic wave matched filter and surface acoustic wave delay lines is provided.