5.6.10 Comparison of modulations 10 Note that there are two typical applications: A-16 QAM M-4 PAM M=64 QAM M=8 PAM(SSB) 1)Band-limited which demands high (SSB) PSK special efficiency,QAM is the best, ZH/(s/Sq)M/ M=16 3 for its required Eb/No is relatively 8 small. M=4 PSK M=2 PAM Bandwidth-limited 2)Power-limited which demands low (SSB) -1.6 region energy,FSK is an option,for its M-2 10 15 2025 required Eb/No can be very small. Asymptote! PM=8 SNR per bit,P=/No(dB) Shannon 0.5 Power-limited Limit M=16 R region:帝< 0.3 M=32 Fig 5.66 on p341. -0.2 M=64 Orthogonal signals Coherent detection 0.1 UESTC-Digital transmission through the AWGN channel Prof李晓峰 8