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提出一种基于自相关函数的频率估计方法.对归一化的自相关函数计算相邻共轭乘积,通过近似处理将乘积表达式中信号与噪声的相乘关系转化为相加关系,然后推导满足最大似然估计准则的窗函数,最后对乘积加权平均得到频率估计值.该方法主要优势是频率增大时依然保持较低的信噪比门限,频率越大优势越大.仿真结果表明在保证-1dB的信噪比门限前提下,估计范围仍能达到理论值的99%.进一步增强处理后,信噪比门限还能降低约1.5dB.同时满足了频率估计中的低信噪比门限和大估计范围两项要求.
A frequency estimation method based on autocorrelation function is proposed.An adjacent conjugate product is calculated for the normalized autocorrelation function and the multiplication relationship between the signal and the noise in the product expression is converted to an additive relation by approximate processing and then deduced The window function that meets the maximum likelihood estimation criterion is obtained, and finally the frequency estimation value is obtained by weighted averaging of the products. The main advantage of this method is that the threshold of signal-to-noise ratio is kept at a higher frequency and the greater the frequency, the greater the advantage. Assuming a signal-to-noise ratio threshold of -1dB, the estimated range can still reach 99% of the theoretical value.After the further enhancement processing, the signal-to-noise ratio threshold can be reduced by about 1.5dB.At the same time, the low signal- And large estimated range of two requirements.