解決射頻功率檢測挑戰

　　大多數射頻設備必須監控并控制其射頻功率輸出，以符合政府的規定，盡量減少射頻干擾，并盡量減少電力使用。發射機也這樣做有明顯的原因：1）最大限度地減少發射功率，增加運行時間和2），以盡量減少功耗。

　　對于接收到的信號路徑，射頻功率檢測也是一個關鍵的功能。這是需要監測接收到的射頻功率調整增益，在RSSI（接收信號強度指示器）是用于控制射頻/增益如果通過AGC（自動增益控制）信號鏈電路為了保持恒定，為后續的模數轉換優化信號電平（如果有）和解調。RSSI信號也被用來控制發送信道，從而最大限度地減少發射功率，同時還保持一個可接受的最小誤碼率（誤碼率）。由于這些原因，準確的射頻功率檢測是重要的兩個接收器和發射機。

　　Note that this RF power detection differs from RF power measurement， although there is some confusion， ambiguity， and overlap in the terminology. RF power detection is generally used to refer to the measurement of the RF power （usually as a relative value） as represented by a voltage （and current） within an electronic circuit; in contrast， RF power measurement is direct measurement of the power （usually as anabsolute value） of the RF wireless signal in space or air.

　　For the former situation， various ICs and modules are used within a circuit; for the latter， specialized sensors （often based on thermocouples） intercept the impinging RF energy and then convert its heat energy to a voltage corresponding to the RF power. ［Recall that power and energy are intimately related parameters： energy is the time integral of power， while power is the time derivative of energy， the rate at which energy is being received or sourced.］