CAJ | 학술논문

提出采用带通滤波和小波包变换对响应信号进行预处理，再由FFT分析和处理获得系统频率特性曲线的方法，较好地解决了低信噪比下的系统频率特性测试问题，并降低了测试时对采集系统的硬件要求。实验结果表明：对于截止频率以下的频段，在信噪比较低甚至为-20 dB时，可以得到精度不低于1 dB的幅频特性曲线和不低于3°的相频特性曲线，完全满足系统性能评价和控制器设计的应用要求。
제출채용대통려파화소파포변환대향응신호진행예처리，재유FFT분석화처리획득계통빈솔특성곡선적방법，교호지해결료저신조비하적계통빈솔특성측시문제，병강저료측시시대채집계통적경건요구。실험결과표명：대우절지빈솔이하적빈단，재신조비교저심지위-20 dB시，가이득도정도불저우1 dB적폭빈특성곡선화불저우3°적상빈특성곡선，완전만족계통성능평개화공제기설계적응용요구。
A method using band-pass filter and wavelet packet transform to pre-treat signal and then using FFT analysis and treatment to get frequency response diagrams is described. This method is better to solve the problems that frequency characteristic test of the system is under low SNR,and reduce hardware requirements of acquisition system in the test. The research show that when SNR is very low and even negative 20 dB value,the amplitude-frequency characteristic that accuracy is not less than 1dB and phase frequency response curve that accuracy is not less than 3°can be obtained for frequency bands that is below the cutoff frequency,which fully meet the system performance evaluation and controller design application requirements.