大时带积线性调频信号源幅相误差分析与校正

Analysis and Calibration of the Amplitude and Phase Errors in High Time Bandwidth Product LFM Signal Generators

针对产生LFM信号的数字方法 ,分析了系统的幅相误差来源 ,并根据误差频率对其进行了分类。提出了一种将正交调制LFM信号产生系统的幅相误差映射到基带后 ,在数字域利用复系数FIR滤波器进行校正的方案。针对直接数字波形合成LFM信号产生系统 ,将误差校正方法简化为直接对存储的数字波形进行预失真处理。最后将校正方法应用于实际系统 ,结果表明提出的幅相误差校正方案易行、有效 ,能明显提高输出LFM信号的性能。

The possible sources of amplitude and phase errors are analyzed for digital LFM signal generators. The errors are classified according to their frequency. The amplitude and phase errors of the LFM signal generators using quadrature modulation technology are mapped into baseband. Then a method using complex coefficients FIR filters to calibrate the errors in digital domain is presented. This method is simplified by pre-distorting directly the stored waveform data for the direct digital waveform synthesis system. The error calibration method is applied to a practical system and the signal performance is significantly improved, proving that the method is easy to use and effective. [