热噪声

LectureNotesfor04116~04118#122006/10/231/3AWGNAdditiveWhiteGaussianNoise(ThermalNoise)4.8.20msµsns()XtABA.X(t)80%4.560%3.5BX(t)10()Xt()10Xt−90%()Xt101±V80%±0.5V0NKT=231.3810K−=×TBKTB1.BKTBpaKpaKKTB()paKKTBF1F≥FNoiseFigureKTFBKTB()1KTBF−Fig.12.LKTBKTLB1/LL3.LectureNotesfor04116~04118#122006/10/232/3niipaKiFi()1iFKTB−1i−()11iipaFKTBK−−1()1211iipaPapaFKTBKKK−−Fig.1Fig.21()12111iniipaPapaFKTBKKK−=−∑nF()()121111iniipaPapaFKTBFKTBKKK−=−−=∑121112121221111111inninipaPapapapapapapapaFFFFFFKKKKKKKKK−−=−−−−=+=++++∑aTaTFKTBF()1TFTFT=+−()1eTFT=−eTLectureNotesfor04116~04118#122006/10/233/3TF()1eTFT=−aT()()01aeaNKTTKTFT=+=+−⎡⎤⎣⎦()()01222aaeKTFTKTTN+−⎡⎤+⎣⎦==()Hf0()2202NHfdfσ∞−∞=∫B()Hf()HfB()Hf()Hf120NBσ=