| 摘要 |
PURPOSE:To contrive the improvement of the communication quality by connecting a transmitter and a radio equipment via an isolation transformer or a relay circuit. CONSTITUTION:A microphone unit 3a is connected to the primary side of a transformer 4d of an interface circuit 4 and its one terminal is connected to a ground line of an enclosure 8. The transformer 4d is used to apply impedance matching and to isolate the ground line of the enclosure 8 and the radio equipment 1. One terminal of the secondary side of the transformer 4d is connected to a contact (a) of a relay 4c and a common terminal of the relay 4c is connected to a transmission signal output of a transmission circuit 1a of the radio equipment 1 and the ground line of the radio equipment 1 is separated from the ground line of the enclosure 8 and the other terminal of the transformer 4d is connected to the ground line of the radio equipment 1. Thus, no power current flows to a signal line and the generation of noise is prevented and the communication quality is improved.
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