基于TMS320C6678的多个同时到达信号脉内调制类型识别

Intra-pulse Modulation Recognition of Multi-simultaneously Arriving Signals Based on TMS320C6678

针对雷达信号脉内调制中的5类信号,提出了一种基于改进相位差分的脉内调制类型识别方法。首先,对信号进行滤波处理,并快速识别出单频脉冲;然后,对滤波后的信号相位差分得到瞬时频率,将瞬时频率等分成两段并利用最小二乘法线性拟合,提取两个参数识别出线性调频和双线性调频;其次,对去跳变后的瞬时频率再利用最小二乘线性拟合提取斜率参数识别出复合信号,对剩下的信号平方后计算3 d B带宽内谱线数是否唯一识别出二相编码信号。最后,基于TMS320C6678实现了5类共7个同时到达信号的调制类型识别。仿真分析表明,当信噪比高于0 d B时,5类信号的识别概率优于90%,硬件实验表明,7个同时到达信号的调制类型识别处理时间在87μs以内。

Considering five typical intra- pulse modulation radar signals, based on improved phase difference, an ap- proach for intra -pulse modulation recognition is proposed. Firstly, the signal is filtered by FFT, and monopulse is recog- nized fastly, the instantaneous frequency of the filtered signal is calculated by phase difference, the instantaneous frequency is divided into two sections equally, least squares linear fit method is used to extract two parameters, which are used for the recognition of LFM and DLFM, and then instantaneous frequency＇ s trip points are removed, LFM - BPSK is recognized through slope rate, which is calculated by least squares linear fit method again, the last signal is recognized through judging the bandwidth of the squared - signal. The algorithm is realized on TMS320C6678, and seven simultaneously arriving signals are recognized. Simulation results show that the recognition rate of five signals can reach 90% when SNR is above 0 dB, the hardware implementations are easy, and the total process time of seven simultaneously arriving signals is less than 87μs.