The functions of Transformation Modulation: Spectra Matching, Better performance/cost seekin Amplification: Signal/Noise Improving Equalization: Channel Characteristic Adjusting Source Coding: Transmission Efficiency Bettering Channel coding: Noise Immunity Cryptographic Coding: Security ProtectionThe Functions of Transformation - Modulation: Spectra Matching, Better Performance/Cost Seeking - Amplification: Signal/Noise Improving - Equalization: Channel Characteristic Adjusting - Source Coding: Transmission Efficiency Bettering - Channel Coding: Noise Immunity - Cryptographic Coding: Security Protection