5.2 Pulse amplitude modulation 5.2.1.PAM:signal expression. The signal 'element'is a rect pulse,and generally,can be of other shapes. Agr(1) A -Ag() “11” Pulse Amp Modulation “10” For polar 2-PAM,4 are “01” A and -A. “00” For polar 4-PAM,4 are 3A,A,-A and-3A. Generally,let g()be the pulse,the signals for M symbols is, s(t)=Agr(t) m=1,2,.,M where are amps. UESTC-Digital transmission through the AWGN channel Prof李晓峰 6