Performance study on the two methods of IF digital coherent detection

The direct IF sampling and digital coherent detection technique has important application in the modern radar. This paper studies the performances of the typical digital coherent detection methods such as Hilbert transform method and interpolation method etc. Utilizing LFM signal, we present the method that can test the quadrature performance of IF digital coherent detection by using pulse compression. Upon this method we give the relation of the quadrature performance and the order of Hilbert filter and interpolation filter, and draw some conclusions on the quadrature performance. We point out that direct IF digital coherent detection leads to SNR loss and obtain the losses of two methods by simulations.