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A frequency estimation algorithm of sinusoidal signal was presented. It consists of a coarse frequency estimation followed by fine frequency estimation. Discrete Fourier transform (DFT) determines the coarse frequency estimation and least squares estimator (LSE) makes it possible to get the optimal frequency difference estimation. Subsequently, we derive the relationship between the asymptotic error variance (AEV) and the Cramer-Rao bound (CRB). Simulation results show that the performance of the proposed algorithm approaches the CRB of the sinusoid when the signal-to-noise ratio (SNR) is higher than the SNR threshold.

In the communication fields, blind estimation of multi-phase shift keying (MPSK) signal carrier frequency is a central issue of research, and there are many appropriate algorithms to realize it. But in some applications like electronic reconnaissance, there is no priori knowledge for signal parameters, so the receiving bandwidth will be usually much wider than that of the receiving signal. That will result in bad estimation accuracy of carrier frequency. To solve this problem, an accurate blind estimation algorithm of MPSK carrier frequency is proposed in this paper. The algorithm can be used in low signal to noise ratio (SNR) and wide receiving band without any prior knowledge. The estimation accuracy of BPSK carrier frequency is analyzed and the SNR threshold is given. Simulations show that the MPSK carrier frequency estimation accuracy of this algorithm is closed to Cramer Rao Bound (CRB) even in low SNR.