基于MWC压缩采样宽带接收机的雷达信号脉内调制识别

针对传统宽带数字接收机在接收宽带雷达信号时产生的跨信道问题，以及低截获概率(LPI)雷达信号脉内调制盲识别问题，该文提出一种基于调制宽带转换器(MWC)离散压缩采样的新型宽带数字接收机结构对宽带雷达信号进行截获和识别。该结构采用伪随机序列将接收信号混频至基带和其他子带内，经低通滤波、降速采样获得基带压缩采样信号，解决了跨信道信号问题；又提出一种基于短时傅里叶变换(STFT)和频谱能量聚焦率检验的识别算法。首先检验STFT频谱带宽并进行调相和调频信号粗识别，然后检验压缩采样信号频谱能量聚焦率并进行具体的信号脉内调制识别。仿真结果证明了该新型接收机结构和该识别算法在低信噪比下的有效性。

Intra-pulse Modulation Recognition of Radar Signals Based on MWC Compressed Sampling Wideband Receiver

To solve the cross-channel signal problem when receiving wideband radar signals with the conventional wideband digital receiver, and the blind intra-pulse modulation recognition problem for Low Probability of Intercept (LPI) radar signals, a new wideband digital receiver based on the Modulated Wideband Converter (MWC) discrete compressed sampling structure is proposed to intercept and recognize the wideband radar signals. The proposed structure uses the pseudo-random sequences to mix the received signals to baseband and other sub-bands, the mixed signals are then low-pass filtered and down-sampled to get the baseband compressed sampling data, which could solve the cross-channel signal problem flexibly. Furthermore, a recognition method based on the Short-Time Fourier Transform (STFT) and the spectrum energy focusing rate test is proposed. Firstly, the STFT spectrum bandwidth is tested to distinguish phase modulation signals and frequency modulation signals recognition roughly. Then, the spectrum energy focusing rate of the compressed sampling data is tested to recognize the intra-pulse modulation type specifically. Finally, simulation results validate the efficiencies of the proposed receiver and the proposed recognition method in low Signal-to-Noise Rations (SNR).