| 摘要 |
In a fire alarm system, the transmitters generating different frequency signals, are installed at every section and floor of the building. The different signals are separated in the receiver to classify the section and the floor. In case of the 50-cct. fire alarm installation, the lines connected between the transmitters and the receiver are required only 4 lines compare to the conventional 100-lines. The transmitter consists of an audio oscillator cct. comprising a transistor (1) and a tuning fork vibrator(2).
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