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双语推荐：频谱泄漏

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针对传输线电磁信息泄漏问题,在泄漏数字信号频谱特征研究基础上,采用基带频谱覆盖混淆思想,通过增加冗余同步脉冲数字信号传输,设计传输线电磁信息泄漏防护的相关噪声方法,并对该方法的安全性进行理论证明。在此基础上,结合传输线辐射发射模型对相关噪声的频域发射频谱进行仿真分析。仿真结果表明,该方法可对传输线电磁信息泄漏发射进行有效防护。
Based on the study of leakage digital signal spectrum characteristics ,a correlated noise method for transmission line electromagnetic information leakage prevention was proposed .The new method was implemented by adding a redundancy syn‐chronization pulse digital signal transmission line ,in which the baseband spectrum coverage and confusion was achieved .Mean‐while ,the safety of the new method was proved in theory .On this basis ,the emission spectrum of the designed correlated noise was simulated combined with the transmission line electromagnetic radiation emission model .Further analysis of the simulation results shows that the new correlated noise method can achieve impactful prevention effect for the transmission line electromag‐netic information leakage emission .

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在进行快速傅里叶变换时,对信号进行截断会产生频谱泄漏现象。为减小频谱泄漏的影响,以理论分析窗函数为基础,利用Matlab作为辅助工具绘出汉宁窗、汉明窗、矩形窗、三角窗和布拉克曼窗的时域幅度与频域幅度曲线,分析了频谱泄漏的原理以及各窗函数的特点和性能,提出了在对信号进行截断时,如何通过选择合适的窗函数来减小频谱泄漏对信号分析的影响。用Matlab软件对某一信号进行加窗仿真实验,结果表明:汉宁窗最适合此实验信号,验证了选择合适的窗函数的重要性.
The signal is intercepted in the process of FFT, which will cause spectrum leakage. In order to reduce the effect of spectrum leakage, based on theoretical analysis of window function,using Matlab as a tool to make time domain amplitude and frequency amplitude curve of the Hanning window, Hamming window, rectangular window, triangular window and Blackman window,this paper analyzes the principle of spectrum leakage and the features and functions of the window function, chooses the appropriate window function to cut down the spectrum leakage which is provided. A simulation experiment that window function is added to a singal make full use of Matlab software,the Hanning window is most suitable for the signal in the experiment, verifying the importance of choosing the appropriate window function.

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基频非同步采样时，离散傅里叶变换/快速傅里叶变换(DFT/FFT)频谱会发生泄漏现象，谐波、间谐波频谱相互干扰而影响测量结果，传统的加窗插值方法忽略了其他分量对关注分量的长程泄漏影响。文中首先在 IEC 框架下对加 Hanning 窗的信号进行频谱变换，使其他分量的侧瓣上相邻谱线相位差为180°，利用相邻谱线的矢量和消除长程泄漏对关注分量的影响，从而提出了谐波、间谐波分组测量和精确测量方法，实现了谐波、间谐波具体参数的测量。在此基础上提出了邻近谐波、间谐波分离方法，并进一步通过逐次剔除已知分量在关注谱线上的频谱泄漏值来提高测量精度，当非同步采样且不增加采样数据长度时，有效解决了谐波、间谐波相隔很近时无法准确分离测量的难题。仿真和工程数据均验证了所提方法在 IEC 框架要求下测量的实时性和有效性。
Discrete Fourier transform/fast Fourier transform (DFT/FFT) spectrum leakage will occur during nonsynchronous sampling in fundamental frequency, with harmonics and inter-harmonics spectrum mutual interference affecting the measurement results,while the traditional interpolating windowed FFT method ignores the influence of long-range leakage from other components on the component of concern.Firstly,the spectrum of Hanning weighted signal in IEC framework is transformed,to change side lobes adjacent spectral phase difference to 180 degrees in other components.The vector sum of adjacent lines is used to eliminate the influence of long-range leakage on the component of concern,thereby proposing the group measurement method and accurate measurement method of harmonics and inter-harmonics.The measurement of harmonics and inter-harmonics specific parameters is realized.Based on this, the harmonics and inter-harmonics separating method is presented,and furthermore,by successive remov

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采用快速傅里叶变换(FFT)进行电力系统谐波分析时很难做到同步采样,故造成频谱泄漏,而要得到准确的频谱分析结果就必须对经FFT变换得到的频谱进行校正。详细分析了常用的相位差校正法的几种实现方法,并通过仿真比较了它们的优劣性。
There have difficulties in synchronized sampling during the harmonic analysis of power system using fast Fourier transform (FFT) algorithm, which results in frequency spectrum leakage .So it needs the accurate spectrum value by correc -ting the frequency spectrum obtained by FFT.Three conventional phase difference calibration methods are analyzed in detail ,and their advantages and disadvantages are compared by the simulation .

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介绍了利用DFT分析信号频谱的基本流程,重点阐述了利用DFT分析信号频谱时产生误差的原因,即存在的频谱混叠、频谱泄漏及栅栏效应,并提出了相应的改进方法。实例列举了MATLAB环境下DFT分析信号频率分辨率的影响因素,通过与理论分析的对比,解释了提高频率分辨率与计算分辨率的方法。
The process of spectrum analysis by discrete fourier transform (DFT ) is introduced in this paper ,the reason of error is explained in detail when the signal spectrum is analyzed by DFT ,that is to say ,when there are the spectrum aliasing ,spectrum leakage and picket fence effect in the system ,and the improved method is put forward accordingly .The application procedures are listed in the MATLAB ,the methods of improving the frequency resolution are explained .

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采用快速傅里叶变换(FFT)对调频连续波(FMCW)雷达差频信号进行频谱分析时,存在栏栅现象和能量泄漏的问题。为了提高频率测量精度,提出了一种离散频谱能量重心法与截断长度调整相结合的频率测量算法。能量重心法利用功率谱主瓣内的谱线估计主瓣中心的位置,解决了栏栅现象;在采样信号时域整周期截断后,离散频谱能量泄漏较小,可更精确地估计信号频率。结果表明,该算法频率测量精度高,实现简单,可应用于FMCW雷达系统。
In spectrum analysis of the differential frequency signals for frequency-modulated continuous-wave ( FMCW ) radar by using fast Fourier transform ( FFT ) , the problems of energy leakage and fencing phenomenon exist. In order to improve the precision of frequency measurement, the frequency measurement algorithm that combines discrete spectrum energy centroid method and truncated length adjustment is proposed. The energy centroid method can estimate the position of the main lobe center by using the power spectral lines in main lobe to solve the problem of fencing phenomenon. After the sampling signals being truncated by integral period in time domain, the discrete spectrum energy leakage is smaller, thus the signal frequency can be precisely estimated. The results indicate that the algorithm offers high precision of frequency measurement and ease implementation, it can be applied in FMCW radar system.

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非同步采样条件下采用快速傅里叶变换(FFT)进行介损角测量时,频谱泄漏和栅栏效应造成的误差较大。本文提出了一种基于三角自卷积窗频谱相位差校正的介损角测量算法,介绍了其在高压电容型设备绝缘在线监测系统中的应用。三角自卷积窗具有良好的旁瓣性能,采用三角自卷积窗对信号进行加权能有效减少频谱泄漏对介损角测量的影响;基于三角自卷积窗的频谱校正算法不需求解高次方程,计算量小。在非同步采样情况下,通过对基波频率波动、采样频率变化、介损角真值变化、白噪声影响、谐波变化等情况下的介损角仿真测量实验和实际应用验证了本文算法的准确性和有效性。
With non-synchronization sampling, the spectral leakage and picket fence effect have great influence on the performance of dielectric loss angle measurement when using FFT. A phase difference revise algorithm for dielectric loss angle measurement is presented based on triangular self-convolution window （TSCW）, and the application in on-line dielectric loss angle monitoring of high voltage capacitive-type equipment is introduced in this paper. As the triangular self-convolution window has good side lobe behavior, the new algorithm can improve the accuracy of dielectric loss angle measurement by weighting the signal with TSCW. The simulation and application results, which include fundamental frequency fluctuation, changing of sampling frequency, real value of dielectric loss angle variance, white noise, changing of harmonic component verify the effectiveness and practicability of the algorithm.

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由于无线通信应用的需要,使得采用频谱分析仪进行测量的范围更为广阔。这些测量项目包括信道功率,邻道泄漏功率,占空带宽及谐波失真,在这里介绍以上几种测量项目的新方法。
Due to the need for wireless communication applications,which is measured by the spectrum analyzer a wider range.These measurements include Channel Power,Adjacent Channel Leakage Power(ACP),Harmonic Distortion and Occupied Bandwidth(OBW),A new method of measuring the above project introduced here.

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非同步采样下，快速傅里叶变换方法(fast Fourier transform，FFT)算法不可避免地存在频谱泄漏和栅栏效应影响，且采集数据量多，计算量大。为了实现介损角的快速、高准确度测量，该文提出并建立一种基于时域准同步的介损角测量方法，利用准同步采样算法精确估计采样信号的基波频率，采用牛顿插值法对电压、电流采样信号进行插值重构，获得时域准同步采样序列，通过FFT 频域分析和等效电路模型求解实现介质损耗角的精确计算。这种介损角测量算法不需要利用窗函数和谱线插值算法，能有效改善FFT 的频谱泄漏和栅栏效应影响，采集数据量少，算法简单，便于嵌入式系统实现。仿真实验验证了算法的准确性。
Fast Fourier transform (FFT) algorithm would inevitably suffer from spectral leakage and picket-fence effects under asynchronous sampling. Moreover, it requires massive sampling data and high computational costs. Therefore, this paper proposed a dielectric loss angle (DLA) measurement method based on time domain quasi-synchronous sampling technique in order to realize rapid measurements and high accuracy. Firstly, the fundamental wave frequencies of the original voltage and current sampling signals were estimated accurately with the quasi-synchronization sampling algorithm. Then, the quasi-synchronous sequences of the original asynchronous sampling signals were reconstructed by Newton interpolation algorithm. Finally, the DLA was calculated according to the equivalent circuit model and frequency domain analysis of voltage and current quasi-synchronization sampling sequences based on FFT. The proposed method in this paper can perfectly restrain spectral leakage and picket-fenc

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利用快速傅里叶变换进行模数转换器(ADC)动态参数测试很难做到相干采样和整周期截断,因此非相干采样存在必然性,由此造成的频谱泄漏将影响动态参数的测量结果。针对此问题,提出了一种基于平均频谱测试高速ADC动态参数的方法。基于MATLAB构建了验证平台,采用美国模拟器件公司(ADI)的典型高速ADC产品的行为级动态模型进行了仿真验证。仿真结果表明,在非相干程度最大的情况下,基于不同窗函数的平均频谱测试得到的动态参数误差低于1.67%,且达到了IEEE Std 1241-2000的测试标准,降低了测试系统构建难度和成本。
The test for dynamic parameters of analog-to-digital converters ( ADCs) by the fast Fourier transformation has difficulties in performing coherent sampling and integral period truncation .Therefore, the incoherent sampling is inevitable, and the dynamic parameter measurement result will be disturbed by the spectral leakage .To solve this problem, a method based on the average spectrum is proposed to test dynamic parameters of high-speed ADCs. The verification platform is constructed based on MATLAB .The behavior-level dynamic models of typical high-speed ADCs produced by Analog Devices Incorporation ( ADI) are employed for simulation and verification.The simulation results show that, in the case of the largest incoherence degree, the errors of dynamic parameter meas-urement results are smaller than 1.67% based on the average spectrum method with different window functions , and the test standards provided by IEEE Std.1241-2010 can be reached, and the difficulties and cost in construc-t

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