5.2 Pulse amplitude modulation s(t)=Ag(t)cos2zft 5.2.1.PAM:passband signals +A BPSK A oox。MWM "11 10” MASK "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, M and widely used in wireless transmission. 4PAM E UESTC-Digital transmission through the AWGN channel Prof李晓峰 15