利用FRI技术对QPSK调制信号进行处理，对参数的采样实现信号的降采样，通过计算恢复信号-Using FRI technology to deal with QPSK modulation signal, the parameters of the sampling to realize signal sampling, by calculating the signal recovery

FRI对离散信号的采样，实现降采样过程，采用sinc函数作为采样核-FRI to discrete signal sampling, sampling process, adopts the sinc function as a sample

有限新息率 降采样 有注释 对于理解有限新息率很有帮助(Notes on the limited rate of new down sampling are very helpful in understanding the limited rate of innovation)