[电] cavity-tuned absorption-type fr-cquency meter

kōng qiāng tiáo xié chāo wài chà xíng pín lǜ jì ㄎㄨㄥ ㄑㄧㄤ ㄊㄧㄠˊ ㄒㄧㄝˊ ㄔㄠ ㄨㄞˋ ㄔㄚˋ ㄒㄧㄥˊ ㄆㄧㄣˊ lv4 ㄐㄧˋ