Frequency Estimation And Signal Processing With Sub-Nyquist Sampling

In the domain of modern ECM, the mission of reconnaissance Radar is to determine presence or absence of threat Radar and estimate parameters of it. Radar carrier frequency is one of the most important Radar parameters. So measurement of Radar carrier frequency must be high-speed and precise, can choose and recognize signals in complex environment of ECM. With Large Scale Integrated circuit technique development, it's very important to study techniques of high-speed digital frequency measuring in wide band.In this paper, several algorithms of digital frequency measurement are analyzed, including frequency estimation by PSD and digital channelized filters based on FFT. Simulations of these frequency measurements are performed. Then the method of digital channelized filters combining narrowband precise frequency measurement is discussed in detail. And the scheme based on FFT filters is simulated to prove its performance. To reduce data size of digital receiver, methods of sub-Nyquist sampling are usually needed. At last some schemes of frequency measurement with undersampling rate are summed up. In these schemes, framework with complement theorem is specially analyzed, and some methods of frequency measurement are improved.