IQ调制的过程

正交调制（IQ modulation）

• IQ调制器的相移器原理
• 正交调制数学表达和图形化过程i显示（关键元素都在里面）
• 普通调制的过程
• PAM调制的原理

IQ modulators are versatile building blocks for RF systems. The most common application is generating RF signals for digital communication systems. （正交调制主要用于数字通信系统中产生射频信号）

1. Phase shifter using IQ modulator

1. What’s an IQ Modulator?（什么是正交调制器）
   An IQ modulator is a device that converts baseband information into RF signals. Internally, two double-balanced mixers are combined as shown below. By modulating with both in-phase (I) and quadrature (Q) inputs, any arbitrary output amplitude and phase can be selected.
   By targeting specific points in amplitude and phase, high order modulation is created. Shown below is 16-QAM. There are four possible I values, which decodes into two bits. Likewise for the Q axis. So each symbol can convey four bits of information.
   
   正交调制器

2. 调制原理数学表达式及过程中波形变化
   

4.PAM调制过程

we said that the Pulse Amplitude Modulation (PAM) is an amplitude scaling of the pulse according to the symbol value.




Constellation Diagram