| 摘要 |
PROBLEM TO BE SOLVED: To fix a coupling device onto a distribution line with simple work by placing an electrode in the proximity to a transmission line coated with an insulating material to capacitivly couple the electrode to the transmission line. SOLUTION: Electrodes 15, 16, made of a conductive metal, face each other with an insulated wire 21 put in-between and they are fixed to each other with a bolt 17 and a nut 18. The electrode 16 is provided with a receptacle 19, to which a cable 20 is connected. In a coupling device 7, static capacitance to be combined with a distribution line becomes less in comparison with the coupling device. Although the capacitance depends on the wire diameter, that of an electrode of about 10cm long is about 10 to 100pF, which decreases the level of signals to be received. The signal level drops by about 50 to 60dB in comparison with the case when received a conventional combining device. However, because noise level decreases by 50 to 60dB, too, it is possible to secure the signal-to-noise ratio of the same extent as in the conventional method.
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