counter type frequency meter 计数式频率计

butterfly tuner type frequency meter 蝶形调谐式频率计

butterfly circuit type frequency meter 蝶形电路式频率计

induction type frequency meter 感应式频率计

reentrant type frequency meter 凹腔式频率计

electronic counter type frequency meter 电子计数式频率计

vibrating reed type frequency meter 振簧型频率计 ; 振簧式频率计

counting type frequency meter 计数式频率计

heterodyne-type frequency meter 外差式频率计

bridge type frequency meter 电桥式频率计