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| Figure 14-10 Carrier pilot relaying system (dotted lines indicate carrier controls; MO = master oscillator; REC = receiver; PA = power amplifier; LTU = line tuning unit). (Courtesy, Westinghouse Electric Co.) |

| Microwave Relaying |

| In microwave relaying, the pilot systems of relaying are transmitted over microwave radio channels without significant modification in the modes of operation. This system is not subjected to line faults. As in the carrier system, the microwave channel may accommodate several separate functions in addition to line protection. Because the transmission distances of the microwave |

| Figure 14-11 Basic circuit elements for remote tripping of a circuit breaker over a tone-modulated carrier pilot channel. (Courtesy, Westinghouse Electric Co.) |

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