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. 25, 1995
Filed:
Dec. 15, 1993
Applicant:
Inventor:
Ian J Hirst, Orpington, GB;
Assignee:
Northern Telecom Limited, Montreal, CA;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ; H04B / ;
U.S. Cl.
CPC ...
359110 ; 359153 ; 359173 ; 359179 ; 375213 ; 371 202 ;
Abstract
An optical transmission system comprises amplified forward and return paths between a local station and a remote station. Each amplifier of the forward path has an attenuated loopback coupling its output to the return path. Frequency modulated supervisory signals generated at the local station are returned via the loopbacks. These signals are analysed e.g. by Fourier analysis to obtain a measure of the performance of each amplifier. The system may also be employed for the location of fiber breaks.