超宽带雷达因其距离分辨率高、抗干扰能力强、目标检测和识别能力高等优点,受到世界各国的重视。通常采用倍频器来产生超宽带信号,然而,倍频环节中存在一些影响信号质量的非理想特性。针对该问题,提出利用频谱拼接技术来产生超宽带雷达信号。采样频率越大则输出信号幅度包络失真越小。频谱拼接时间误差小于100 ns时,其主瓣比理想情况增大5%。通过频谱拼接技术能够有效解决幅度失真、高采样频率需要和拼接时间误差等问题。设计了两个直接数字频率合成器同步电路,确保两路正交基带信号同步。频谱拼接技术还能灵活控制信号带宽大小,产生较理想的超宽带线性调频信号。

Ultra-wideband (UWB) radar has caused great attention all over the world, because of its high range resolution, strong anti-interference ability, high target detection and recognition ability etc. At present, UWB signal is usually generated by frequency multiplier, however, the quality of the signal is affected by some non-ideal characteristics in frequency doubling link. To solve the problem, the UWB radar signal is generated by spectrum splicing technology. The larger the sampling frequency is, the smaller the amplitude envelope distortion of the output signal is. Its main lobe increases by 5% than the ideal case when the spectral stitching time error is less than 100 ns. The problems of spectral amplitude distortion, high sampling frequency and splicing time error can be effectively solved by splicing technology. Two synchronized direct digital synthesizer circuit is designed to ensure two base-band signals are synchronized. The ideal UWB linear-frequency-modulation signals also can be produced flexibly by controlling signal bandwidth size using spectrum splicing technology.

TP974