Introduction In this chapter,we focus on how to transmit digital info signals with waveforms. The topics include: 1. Geometric representation of sig waveforms; 2.Diff types of waveforms for digital transmissions; 3.Optimal reception; 4.Performance evaluation on the AWGN channel 5. Comparison of the methods. UESTC-Digital transmission through the AWGN channel Prof李晓峰 3