| 摘要 |
PURPOSE:To prevent a cord from being converted to a transmitting antenna by providing electronic parts or an electronic circuit for making a voice frequency pass through but cutting off an unnecessary frequency, on an optional position of the cord of a device. CONSTITUTION:An unnecessary frequency cutting-off part 6 is positioned between a connector 5 and a sound converting part 4, and the length l1-b of a cord 1-b between the connector 5 and the cutting-off part 6, or the length l1-c of a cord 1-c between the cutting-off part 6 and the sound converting part 4 is in a distance of l1-b<lambda/4 or l1-c<lambda/4 against a wavelength lambda. The cutting-off part 6 is constituted of an inductance 6-a for cutting off a high frequency. According to such a constitution, a voice frequency passes through said cutting-off part 6 without any obstruction, but an unnecessary frequency except the voice frequency concerned is cut off, therefore, this device can be used as a usual sound converting device, and also it is possible to reduce remarkably the conversion to a transmitting antenna contributed to an unnecessary radiation. |
