5.2 Pulse amplitude modulation Snm(I)=Angr(I)） 5.2.1.PAM:baseband and passband "11 种10 ”01 "00 2PAM Antipodal Baseband signal:its freq band is close to zero, often used in wire-line transmission. 2PAM Unipolar Passband signal:its freq band is away from zero, a cos-like waveform, and widely used in wireless transmission. 4PAM A=1 UESTC-Digital transmission through the AWGN channel Prof李晓峰 12