Design and realization of digital frequency discriminator based on FPGA

For pulse Doppler active homing end-guidance radar seekers, an algorithm and its realization with FPGA are proposed for getting single Doppler frequency in digital velocity-tracking loop. Digital down converters are used to reduce sample-rate of zero-IF singals, then phase information is gotten by a digital phase discriminator, and phase difference is calculated to get the Doppler frequency. This algorithm compensates the error brought about from Doppler frequency surveying by a group including few coherent filters in digital velocity-searching loop, and the velocity-tracking precision is improved. The method of the realization of digital frequency discriminator with FPGA is introduced concretely. Simulation and analysis on the design and its actual application show this method works well.