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:
Dec. 03, 1991
Filed:
Aug. 01, 1989
Shinichi Horinouchi, Yokohama, JP;
Kunihiko Takeuchi, Kawasaki, JP;
Tokyo Keiki Company Ltd., Tokyo, JP;
Abstract
The bidirectional transmission to write or read out data is executed between a read/write unit and a memory module by the contactless electromagnetic coupling using induction coils. A spread spectrum communication technique is used in at least the up transmission to transmit data from the memory module to the read/write unit in the bidirectional transmission. Two kinds of chirp waves or M series having little correlation are used in the spread spectrum communication. For instance, in the case of using the chirp waves, on the transmission side, two kinds of chirp waves having little correlation are prepared and either one of the chirp waves is transmitted in correspondence with the data bit 0 or 1. On the reception side, the correlation between the reception signal and each of the reference values of the two kinds of chirp waves which have previously been stored is calculated and the data bits 0 and 1 are demodulated on the basis of the result of the calculation. Further, a frequency code signal including a combination of a preamble, a terminator, data, and a terminator is used in the down transmission from the read/write unit to the memory module.