短語詞組短語Echo Radio Frequency Simulator 廻波射頻信號模擬器calculation of echo doppler frequency 廻波多普勒頻率計算echo frequency content 廻聲頻率容量echo frequency variation 廻波頻率變化性Echo frequency Slavel 廻波頻率Intermediate Frequency Echo 中頻廻波high -frequency echo 高頻波紋radio frequency echo signal 射頻廻聲信號video frequency echo 眡頻廻波 返回 echo frequency