无线电磁听音原理

无线电磁听音系统是电磁感应原理的实际应用，在发送端，将放大的音频信号电流，通过长直导线形成随音频变化的多变磁场，在接收端，用线圈感应出音频电流，放大后通过耳机恢复成语音信号，无线电磁听音系统的辐射线，是扩音机输出负载，要求辐射回路总阻抗与扩音机输出阻抗相等或接近，以求得到最大输出功率，根据右手则，布线时要使辐射环路与磁声场方向始终保持一致，防止磁场抵销。

Radio Electromagetic Listening System

The radio electromagnetic listening systen is the appliction of electromagnetic iduction,At the sendimg end,through long straight wire,the amplified audio signal curent forms exchanging end of the audio,At the receivingmagnetic the audio current is inducted by coil.After being amplificed it returns into language signal. The radiotion of radio electromagnetic listening system is the exporting load of audio amplifier.The total resistance of radiotion return circuit must be egual or almost equa to resisttance of the audio amplifier.In that way we can get the highest exporting power. Acording to the right hand law when we set the wire,The inside magnetic field direction of radiotion must be kept all the time. In order to avoid the counteraction of magnetic field.