Signal demodulation of automatic block with audio frequency shift modulated track circuits was implemented with phase-locked loop( PLL) technique and a singe chip microcomputer.是什么意思_Signal demodulation of automatic block with audio frequency shift modulated track circuits was implemented with phase-locked loop( PLL) technique and a singe chip microcomputer.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句