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:
Jan. 06, 1987
Filed:
Apr. 25, 1985
Ichiro Kubota, Tokyo, JP;
Masakatsu Toyoshima, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
A bidirectional digital signal communication system includes a plurality of terminal units in communication with a center unit. Each of the terminal units includes a signal generator for generating digital data spread with a PN (pseudo-noise) code, a modulator for modulating the digital data on a carrier, and a transmitter for transmitting the modulated digital signal to the center unit through a transmission line. The center unit includes a receiver for receiving the modulated digital signal, a PN code generator for locally generating a PN code which corresponds to the transmitted PN code, a multiplier supplied with outputs of the receiver and the PN code generator to produce a digital signal de-spread from the PN code, a demodulator connected to the multiplier to reproduce the digital data from the modulated digital signal, and a memory for storing the PN code when the signal level of the multiplier exceeds a predetermined value. The stored PN code is retrieved from the memory to enable rapid synchronization with the next transmission received from the terminal unit.