# 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

