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:
Feb. 14, 1995
Filed:
May. 16, 1994
Noboru Yamamoto, Fujisawa, JP;
Kenji Nakamura, Hadano, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
When a communication network system is constructed using an optical fiber as a transmission path, a node which transmits a signal may receive its own transmission signal upon reflection of an optical signal on the transmission path. When access control to a network is performed by a CSMA/CD method, the reflection signal may be erroneously detected as a signal sent from another node, and a collision which has not actually occurred may be detected. In order to avoid this, a reflection signal component of the transmission signal must be removed from a reception signal. For this purpose, a time-inverted signal of the transmission signal, and the reception signal are modulated, and the modulated signals are then input to a convolver, thereby obtaining a convolution integral value between the two signals. Since the transmission signal component included in the reception signal can be detected from the obtained value, the detected transmission signal component is removed from the reception signal component, and a signal transmitted from another node can be extracted. In this manner, erroneous detection of a collision upon reflection of a signal transmitted from its own node can be prevented.