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:
Jul. 14, 1987
Filed:
Aug. 16, 1985
Kouzou Kage, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A digital signal repeater system, including means for controlling the transmitter of the system. The system is substantially immune to fading, interference and noise, and rapidly detects the reception of a digital signal. A first level detector outputs a logical 1 signal to indicate reception of a signal, in response to the level of the IF signal in the receiver. A second level detector indicates when the received signal is digital by filtering the demodulated received signal and generating a logical 1 output when the received signal has a substantial component at a predetermined clock frequency. The two logical output signals are applied to an AND gate and the output is smoothed and compared by a comparator to a reference level. The output of the comparator is used to control the transmitter. In another embodiment, a third level detection circuit determines whether the clock frequency signal has been detected for a comparatively long period of time and, if so, lowers the reference level supplied to the comparator to stabilize its output.