Modulations
ASK
Amplitude-shift keying
FSK
Frequency-shift keying
PSK
Phase-shift keying (1正向 0反向)
DPSK
Differential Phase-shift keying (相对前一个，1反向 0同向)
各种编码
NRZ
Non Return to Zero codes
RZ
Return to Zero
CMI
Coded Mark Inversion
AMI
Alternative Mark Inversion
HDB3
High Density Bipolar of Order 3 code