20160521Bandpass-sampling

代码说明：

  分析带通采样定理的原理和实现过程，说明带通信号重构原始信号的方法，仿真给出不同采样频率和低通采样性能对比(By analyzing the principle and implementation process of the bandpass sampling theorem, the method of reconstructing the original signal with the signal is explained, and the performance comparison of different sampling frequency and low pass sampling is given.)