线路编码方案小结 Table 4.1 Summary of line coding schemes Bandwidth Category Scheme (average) Characteristics Unipolar Nrz B=N/2 Costly,no self-synchronization if long 0s or 1s,DC NRZ-L B=N/2 No self-synchronization if long Os or 1s,DC Unipolar NRZ-I B=N/2 No self-synchronization for long Os,DC Biphase B=N Self-synchronization,no DC,high bandwidth Bipolar AMI B=N/2 No self-synchronization for long Os,DC 2B1Q B=N/4 No self-synchronization for long same double bits Multilevel 8B6T B=3N/4 Self-synchronization,no DC 4D-PAM5 B=N/8 Self-synchronization,no DC Multiline MLT-3 B=N/3 No self-synchronization for long Os 4.364.36 Table 4.1 Summary of line coding schemes 线路编码方案小结