带通采样定理与中频采集数字正交检波

Bandpass Sampling Theorem and Digital Quadrature Coherent Detection

结合对带通采样定理的理解,讨论了直接中频带通信号采样正交检波的基本原理,重点探讨正交混频低通滤波法和希尔伯特变换频移法。利用对带通采样定理的理解,扩展其应用范围,给出了适用条件、原理框图以及信号流图。最后用仿真实例验证了扩展方法的可行性,对工程实际有一定的参考意义。

Fundamentals of IF （ Intermediate Frequency ） bandpass signal sampling and quadrature detection are discussed, especially the coherent mixing LPF method and Hilbert transform frequency-shift method. In-depth comprehension of bandpass sampling theorem allows expanding the application fields, and applicable condition, principle diagram and signal - flow graphs are given respectively. These results help to understand and utilize quadrature coherent detection. Finally, simulation examples are given to validate the effectiveness of proposed methods.