声频电报
audio frequency telegraph
Telegraphy
acoustic
voice-frequency telegraphy
声频磁法
AFMAG
audiofrequency magnetic method
Afmag method
声频磁场技术
audiofrequency magnetic technique
声频磁场
audiofrequency magnetic field
声频产生器
acoustic frequency generator
Generator
acoustic frequency
audio frequency generator
AFG
声频测速
sound-frequency speed measurement
声频测量仪器
acoustic frequency measuring instrument