sub-GHz IC具有小數(shù)N分頻鎖相環(huán)的雙向遙控車門開關(guān)的設(shè)計

　　雙向遙控鑰匙（RKE）系統(tǒng)為用戶提供安全和便利。對于設(shè)計師，一個復雜的IC陣列提供完整的收發(fā)器功能，利用未經(jīng)授權(quán)的ISM頻段。其中，sub-GHz收發(fā)器集成電路從模擬設(shè)備，飛思卡爾半導體和集成功能的小數(shù)N分頻鎖相環(huán)在先進的雙向RKE系統(tǒng)設(shè)計更大的靈活性。

　　傳統(tǒng)的無線設(shè)備，如汽車的鑰匙是為了打開門，允許使用的金屬鑰匙啟動發(fā)動機。后來RKE系統(tǒng)添加被動進入（PE）的能力，在關(guān)鍵的集成無源低頻轉(zhuǎn)發(fā)器鏈作為授權(quán)過程的一部分來解鎖，解鎖轉(zhuǎn)向，沒有金屬使用鑰匙啟動發(fā)動機。更高度集成的設(shè)備的可用性，制造商繼續(xù)提供RKE應(yīng)用大大增強功能，提供更方便的功能，在越來越多的RKE應(yīng)用包括車輛出入，建筑訪問安全性提高，和其他。

　　Advanced transceivers

　　At the heart of these enhanced two-way RKE systems， advanced transceivers operating in the unlicensed ISM band offer the combination of high output power， high receiver sensitivity， and low power consumption increasingly required in two-way RKE applications. Advanced ISM transceivers enable two-way HF communications for both traditional RKE and PE applications. Compared to LF communications， HF communications offer greater operating range， and improved data rates support more sophisticated wireless applications. Available HF transceivers boast receiver sensitivity better than -100 dBm and can deliver transmitter power above 10 dBm. At the heart of devices such as the Analog Devices ADF7020， fractional-N PLLs offer multiple advantages （Figure 1）.