飞机脱离航道时,会有一个无线电信号告诉驾驶员。 A radio signal tells the pilot of an airplane when his plane is off the beam.
膜片,振动板一种薄的圆盘(尤其是在麦克风和电话收话器里那种)响应声波振动产生信号或者响应电信号振动产生声波 A thin disk, especially in a microphone or telephone receiver, that vibrates in response to sound waves to produce electric signals, or that vibrates in response to electric signals to produce sound waves.
由两根外皮绝缘的导线扭在一起组成的一种类型的传输媒体,扭在一起是为提高对可能破坏被传输信号的其它(杂散)电信号的抗扰度。 A type of transmission medium consisting of two insulated wire twisted together to improve its immunity to interference from other(stray) electrical signals that may otherwise corrupt the signal being transmitted.