QPSK意为正交相移键控，是一种数字调制方式在电路上实现较为简单。它不仅可以节约频谱资源而且可以提供良好的通信性能。QPSK调制是一种具有较高频带利用率和良好的抗噪声性能的调制方式，在数字移动通信中已经得到了广泛的应用。 本次设计在理解QPSK调制 ...

4PSK信号是两个载波正交的2PSK信号的合成。所以，可以仿照2PSK相干检测法，用两个正交的相干载波分别检测两个分量 a和b，然后还原成二进制双比特串行数字信号。此法称作极性比较法（相干解调加码反变换器方式或相干正交解调法） 判决器是按极性来判决的。

The modulators are the basic requirement of the communication systems they are designed to reduce the channel distortion & to use in RF communication hence many type of carrier modulation techniques ...

(c) Capacity in bits per second per Hertz vs. Bit to Noise Ratio (Capacity vs Eb/No) (d) Bit Error Rate vs. Bit to Noise Ratio (BER vs Eb/No) Symbol Error Rate vs. Es ...

The demand for greater data throughput seems endless, and it is accelerating faster than many people expected, creating bottlenecks in fiber-optics networks. Digital transmissions of 100 Gbps, which ...