5.2 Pulse amplitude modulation 5.2.1.PAM:Binary=info bits are 1 and 0 Pulses of amp A and-A is used,called antipodal (or polar)signaling. +A一|十一 +1-1+1+1-1-1-1+1+1-1+1 +1 Alternately,A 0 0 pulse of amp A and 0 may be used,called unipolar signaling. If one bit takes an interval of 7 seconds,the rate of signaling is R,=1/T,bps (bit-per-sec). UESTC-Digital transmission through the AWGN channel Prof李晓峰 3