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.

Date of Patent:
May. 27, 2003

Filed:

May. 25, 2001
Applicant:
Inventors:

Yoshihiro Matsumoto, Tokyo, JP;

Takashi Kuriyama, Tokyo, JP;

Yoshinori Honma, Tokyo, JP;

Masashi Tachigori, Tokyo, JP;

Assignee:

NEC Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J 4/014 ;
U.S. Cl.
CPC ...
H01J 4/014 ;
Abstract

A photo receiver branches a data signal obtained by photoelectric conversion and supplies the signal to a signal cutoff detector. Depending on the degree of an autocorrelation of a data signal obtained by an autocorrelation detector, the signal cutoff detector detects abnormality/normality. Depending on a level of a control signal to a VCO contained in a frequency phase-locked loop for use in clock generation, an out-of-synchronization detector makes determination of abnormality/normality. Outputs of both the detectors are ORed at an alarm processor and when at least one of the detectors detects abnormality, the detector generates an alarm.


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