基带

基带信号的频谱，单位频率的能量 E 作为频率 f 的函数。总能量是线下的面积。
此條目介紹的是信号处理的概念。关于无线数字通讯的信号处理器，请见「基带处理器」。

基带（英語：baseband）是频率范围非常窄的信号，也就是说幅度谱仅在原点（f = 0）附近才是非零的，其他频率几乎可以忽略。[1] 在电信与信号处理中，基带信号是未经载波调制的信号，即该信号的频率范围没有任何移位，[2] 而且频率很低 - 包含频带从接近 0 Hz到更高截止頻率或最大带宽。

由于基带信号是未经载波调制的信号，在GPS接收机和移动电话等无线数字通讯领域，基带信号有时也泛指已经过射频前端（英语：Radio Frontend）处理后的信号。[3][4]在无线通讯设备中，来自天线的信号先经射频前端（英语：Radio Frontend）的模拟电路接收，然后再转交给后续的数字电路进一步处理，而后者就是基带处理器。[3][4]在当前中文语境中，手机基带处理器所带的固件也简称“基带”[5]。

参见

参考文献

  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. 
  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]. （原始内容存档于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. ^ 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 (报告). 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]. （原始内容存档于2016-02-07）.