左边带本振SNYFR接收的LFM信号参数估计算法

同步Nyquist折叠接收机（SNYFR）利用双片模数转换器同时完成多Nyquist区域内的宽频段信号采集，为一种新型侦察接收机结构，在SNYFR结构上提出了线性调频（LFM）信号的参数估计算法。首先从频谱关于采样率对称的本振信号出发，指出其Nyquist区域在某些条件下不存在；其次提出了Nyquist区域存在的左边带本振SNYFR；以正弦调频本振信号调制频率为频率抽取因子进行序列构造，并以此序列估计Nyquist区域；最后在区域估计的基础上，得到欠采样的LFM信号，并完成参数估计。仿真表明，LFM参数估计精度在信噪比优于10dB时均已接近克拉美-罗下限。

Parameter Estimation of LFM Signal Intercepted by Left Sideband Synchronous Nyquist Folding Receiver

Synchronous Nyquist folding receiver(SNYFR) is a new kind of interception architecture,which could simultaneously intercept wideband signals in multi-Nyquist zones with two analog-to-digital converters(ADCs).A parameter estimation algorithm is presented for the linear frequency modulated(LFM) signal intercepted by an SNYFR.First,taking the local oscillator signal(LOS) whose spectrum is symmetrical about the sampling rate as an example,the Nyquist zone does not exist under certain conditions.Second,the left sideband LOS SNYFR,whose zone does exist,is proposed.Then,the frequency decimation factor is designed as the modulated frequency of the sinusoidal frequency modulation(SFM) LOS to estimate the Nyquist zone.Finally,the under-sampled LFM signal is reconstructed by using the zone,and it is used to estimate the parameters of signal.Simulations show that all the parameter estimation accuracies are all close to Cramer-Rao lower bounds when the signal to noise ratio(SNR) is above 10dB.