基頻

基頻（英語：baseband）是頻率範圍非常窄的訊號，也就是說振幅譜僅在原點（f = 0）附近才是非零的，其他頻率幾乎可以忽略。^[1] 在電信與訊號處理中，基頻訊號是未經載波調變的訊號，即該訊號的頻率範圍沒有任何移位，^[2] 而且頻率很低 - 包含頻帶從接近 0 Hz到更高截止頻率或最大頻寬。

由於基頻訊號是未經載波調變的訊號，在GPS接收機和行動電話等無線數位通訊領域，基頻訊號有時也泛指已經過射頻前端（英語：Radio Frontend）處理後的訊號。^[3]^[4]在無線通訊裝置中，來自天線的訊號先經射頻前端（英語：Radio Frontend）的類比電路接收，然後再轉交給後續的數位電路進一步處理，而後者就是基頻處理器。^[3]^[4]在當前中文語境中，手機基頻處理器所帶的韌體也簡稱「基頻」^[5]。

參見

參考文獻

^ Leon W. Couch II. Digital and Analog Communication Systems. Prentice Hall. 1993.
^ B.P. Lathi. Modern Digital and Analog Communication Systems. Holt, Rinehart and Winston. 1983.
^ ^3.0 ^3.1 Christian Piguet. 6: Low-Power Bandband Processors for Communications. Low-Power Processors and Systems on Chips. CRC Press. [2020-01-10]. （原始內容存檔於2020-04-26）. Baseband Signals are all signals in a radio system, which are not modulated onto the carrier wave. In a cellular phone, this means all signals except those in the radio frequency (RF) part of the phone.
^ ^4.0 ^4.1 U.S. International Trade Commission. In the Matter of Certain GPS Chips, Associated Software and Systems, and Products Containing Same, Investigation No. 337-TA-596 (報告). DIANE Publishing: 6. A GPS receiver typically includes an analog signal processing portion in a radio-frequency circuit (an "RF Front End") and a digital signal processing portion in a baseband circuit (a "Baseband Processor"). In a GPS receiver, the RF Front End receivers the GPS signal, filters and amplifies the signal, and converts the resulting signal into a digital formbat. The resulting digital signal, which is sometimes referred to as the "baseband signal," is sent to the Baseband Processor.
^ 基带是什么. 太平洋IT百科. [2016-02-07]. （原始內容存檔於2016-02-07）.

[1] Leon W. Couch II. Digital and Analog Communication Systems. Prentice Hall. 1993.

[2] B.P. Lathi. Modern Digital and Analog Communication Systems. Holt, Rinehart and Winston. 1983.

[mobile-3] 3.0 ^3.1 Christian Piguet. 6: Low-Power Bandband Processors for Communications. Low-Power Processors and Systems on Chips. CRC Press. [2020-01-10]. （原始內容存檔於2020-04-26）. Baseband Signals are all signals in a radio system, which are not modulated onto the carrier wave. In a cellular phone, this means all signals except those in the radio frequency (RF) part of the phone.

[gps-4] 4.0 ^4.1 U.S. International Trade Commission. In the Matter of Certain GPS Chips, Associated Software and Systems, and Products Containing Same, Investigation No. 337-TA-596 (報告). DIANE Publishing: 6. A GPS receiver typically includes an analog signal processing portion in a radio-frequency circuit (an "RF Front End") and a digital signal processing portion in a baseband circuit (a "Baseband Processor"). In a GPS receiver, the RF Front End receivers the GPS signal, filters and amplifies the signal, and converts the resulting signal into a digital formbat. The resulting digital signal, which is sometimes referred to as the "baseband signal," is sent to the Baseband Processor.

[5] 基带是什么. 太平洋IT百科. [2016-02-07]. （原始內容存檔於2016-02-07）.

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