| 摘要 |
A method of pulsed OTDR (optical time domain reflectometry) measurement, wherein single OTDR test signals (1) are sent into an optical fiber (2) with an optical light source, is characterized in that the single OTDR test signals are modulated during their duration. The inventive method results in a low level of electrical noise on the backscattered OTDR signal, even if a narrowband optical light source is used in an embedded OTDR system.
A pulse generator (31) generates separate rectangular signals (32),whereas a dummy data source (33) provides continuously a dummy data signal (34). An AND-gate (35) multiplies the signals (32,34) and the generated laser drive signal (36) is fed into a DFB laser (37).
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