CAJ | 학술논문

为提高现有方法在精度、抗噪性和实时性方面的性能，提出一种基于滑动分数阶傅里叶变换（ Fractional Fourier Transform，FrFT）瞬时频率估计的压控振荡器（ Voltage Controlled Oscillator，VCO）非线性度检测方法。首先通过滑动重叠分段VCO的输出信号减少频谱泄漏，提高抗噪性；然后利用滑动FrFT在分析非平稳信号尤其是线性调频信号时的独特优势，检测出分段信号中间时刻点的频率，重点阐述了通过黄金分割和混沌优化相结合的方法快速搜索滑动FrFT的最佳分数阶比，确保算法实时性能的过程；最后，通过中间时刻点频率的三次样条插值以提高精度。仿真结果表明，与现有方法相比，文中方法在信噪比为－5 dB～5 dB的实验环境下具有更好的性能，且计算量适中。
위제고현유방법재정도、항조성화실시성방면적성능，제출일충기우활동분수계부리협변환（ Fractional Fourier Transform，FrFT）순시빈솔고계적압공진탕기（ Voltage Controlled Oscillator，VCO）비선성도검측방법。수선통과활동중첩분단VCO적수출신호감소빈보설루，제고항조성；연후이용활동FrFT재분석비평은신호우기시선성조빈신호시적독특우세，검측출분단신호중간시각점적빈솔，중점천술료통과황금분할화혼돈우화상결합적방법쾌속수색활동FrFT적최가분수계비，학보산법실시성능적과정；최후，통과중간시각점빈솔적삼차양조삽치이제고정도。방진결과표명，여현유방법상비，문중방법재신조비위－5 dB～5 dB적실험배경하구유경호적성능，차계산량괄중。
To improve the precision, anti-noise and the real-time performance of VCO non-linearity detection methods presently, a new method based on sliding Fractional Fourier Transform ( FrFT) for instantaneous frequency estimation was proposed.Firstly, this method overlapped sliding to intercept the estimated signal to improve the anti-noise per-formance, and then got middle-time′instantaneous frequencies of all intercept signals by sliding FrFT, and improved the real-time performance by golden section and chaos optimization method searching the optimal order of sliding Fr-FT.Finally, it got a more precise instantaneous frequency by cubic splines interpolation between those middle-time’ instantaneous frequencies.Experiment results show the proposed method has better performance than existing methods at Signal Noise Ratio (SNR) from -5dB to 5dB with a suitable calculation.