| 摘要 |
PURPOSE: To attain suppression of a common mode current at transmission of a broad band CATV signal by connecting an auto-transformer, a choke transformer and a separated transformer to a circuit respectively. CONSTITUTION: A CATV signal on a video signal port 21 is given to an auto- transformer T1 having 1st to 3rd windings N1-N3, a balanced signal appears between conductors 40, 41, it is given to a choke transformer T2 having 4th and 5th windings N4, N5, its output is fed to a primary winding N6 of a separate transformer T3, and a CATV signal is outputted from the secondary winding N7. The windings N6, N7 of the transformer T3 are connected to ground via center taps 39, 38, a CATV current in the basic mode is supplied to the windings of the transformers T2, T3 in different directions and a common current flows in the same direction, self-inductance and mutual inductance are summed to provide a high impedance with respect to the common current, thereby suppressing the common current. As a result, the CATV signal is sent in an excellent way without using a shielded wire.
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