| 摘要 |
A signal coupler for coupling tone, voice and other signals to a pair of communication wires, such as the tip and ring leads of a telephone line is disclosed. The signal coupler comprises a gyrator, a capacitor and a controllable voltage source. The capacitor and controllable voltage source are series connected to the input of the gyrator. The controllable voltage source is modulated by the signal to be coupled and, in turn, modulates the input of the gyrator. The output of the gyrator is connected across the pair of communication wires, whereby the gyrator modulates the loop holding current in accordance with the nature of the signal to be coupled. As a result, the signal is coupled to the communication wires.
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