| 摘要 |
PROBLEM TO BE SOLVED: To measure the residual wavelength dispersion of an optical fiber transmission path, independently of a bit rate. SOLUTION: A photoelectric converter 20 converts a test signal light propagated by an optical fiber transmission path 12 into an electric signal, in which the output thereof is inputted to a data discrimination circuit 24 through a low-pass filter (LPF) 22. The circuit 24 discriminates the output of the LPF 22 according to a threshold Vth from a threshold generation circuit 26. The threshold generation circuit 26 discretely sweeps the threshold Vth at a suitable constant time interval. An averaging circuit 30 accumulates and averages the discrimination results of the data discrimination circuit 24 for each threshold Vth, and stores the result in a memory 40. A differentiation circuit 42 differentiates the data of the memory 40 with the threshold Vth, and stores the result in a memory 44. A peak detection circuit 46 detects the peak from the storage data of the memory 44. A wavelength dispersion calculation circuit 48 calculates a value indicating the wavelength dispersion value from the threshold corresponding to the detected peak. COPYRIGHT: (C)2005,JPO&NCIPI
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