Patent ID: 6801720
Filing Date: 2004-10-05
Classification: H04B,H04J,H04L

Abstract:
An optical signal quality supervisory device comprising:an optical supervisory channel for supervising the transmission line quality of an optical communication system; main optical channel receiving means that receives a main optical channel transmitted over the optical communication system; and optical supervisory channel receiving means that receives said optical supervisory channel transmitted through the optical communication system to supervise the quality of the transmission line, wherein the bit rate of the optical supervisory channel is made lower than the bit rate of the main optical channel; and wherein said optical supervisory channel receiving means includes: reception discriminating means that receives the signal transmitted through the optical communication system according to one of the following: a) an electric band width of the reception discriminating means being substantially the same as the electric band width of said main optical channel receiving means; and b) the electric band width of the reception discriminating means being wider than the electric band width of said main optical channel receiving means to discriminate and reproduce the optical supervisory channel from the received signal to discriminate and reproduce the optical supervisory channel from the received signal; and error detecting means that has an electric band width being narrower than the electric band width of said main optical channel receiving means and detects an error on the basis of the optical supervisory channel which is discriminated and reproduced by said reception discriminating means.