保密: keep a secret density倒: reverse频: frequent系统: system保密倒频电路: scrambler circuit保密器倒频器: scramlber倒频保密电路: scrambler circuit倒频保密设备: frequency inversion privacy equipment倍频系统: frequency doubling system调频系统: frequency modulation system; frequency-modulated system共频系统: common frequency system扩频系统: band spread system拍频系统: beat-frequency system全导频系统: all pilot system射频系统: radio frequency system; radio-frequency system声频系统: audio system; audion system视频系统: y/c双混频系统: double mixer system稳频系统: frequency stabilizing system选频系统: frequency selective system移频系统: frequency shift system; fs system音频系统: voice frequency system载频系统: carrier frequency system窄移频系统: narrow shift system扰频器倒频器保密器: scrambler