摘 要:調制是將要傳送的信息裝載到某一高頻 (載波)信號上去的過程。振幅調制是用調制信號去控制載波的幅度,使其隨調制信號線性變化,而保持載波的頻率不變。在幅度調制中,根據已調信號的頻譜分量不同,分為普通調幅(標準調幅AM)、抑制載波的雙邊帶調幅(DSB)、抑制載波的單邊帶調幅(SSB)。它們的主要區別是產生的方法和頻譜結構不同。
關鍵詞:載波;調制;調幅;頻譜
Research on Amplitude Modulation
ZHANG Wei,DONG Yunfeng,XIA Yunbo
(Daqing Teachers College,Daqing,163712,China)
Abstract:Modulation is the transmission of information to be loaded onto a high-frequency (carrier) signal in the process.Amplitude modulation using signal to control the rate of carrier,with its linear modulation signal changes,and maintain the same carrier frequency.In the amplitude modulation,in accordance with the strength of signals in the spectrum of different components,it is divided into ordinary AM (amplitude modulation standard AM),with inhibition of bilateral carrier AM (DSB),the carrier single sideband suppression AM (SSB).The main difference is the different methods and structure of the spectrum.
Keywords:carrier;modulation;AM;frequency spectrum
把要傳送的信號裝載到某一高頻振蕩(載頻)信號上去的過程叫做調制,當載波為正弦波信號時,為連續調制。連續波調制以單頻正弦波為載波,受控參數可以是載波的幅度um,頻率ω或相位φ。因而出現了調幅(AM)、調頻(FM)和調相(PM)三種調制方式。
振幅調制是用調制信號去控制載波的振幅,使其隨調制信號線性變化,而保持載波的頻率不變。在幅度調制中,根據所取出已調信號的頻譜分量不同,分為普通調幅(AM)、抑制載波的雙邊帶調幅(DSB)、抑制載波的單邊帶調幅(SSB)。