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:
Apr. 18, 1989
Filed:
Jul. 07, 1986
Yasuharu Yoshida, Tokyo, JP;
NEC Corporation, , JP;
Abstract
In a digital transmission system, a clock regeneration circuit includes a phase-locked loop having a low-pass filter, a voltage-controlled oscillator connected thereto, and a phase comparator for supplying to the low-pass filter a signal representative of the phase difference between an incoming two-level data bit stream and the output of the voltage-controlled oscillator. The incoming data bit stream is converted into a plurality of parallel data bit streams and fed to a multi-level quadrature amplitude modulator in response to a clock signal derived from the output of the voltage-controlled oscillator and converted into an outgoing multi-level digital signal. An incoming CMI (coded mark inversion) coded binary signal is sampled by a flip-flop for in response to the output of the voltage-controlled oscillator to supply an output signal to the VCO through the low-pass filter.