| 1. | A fast fourier transformation based second order reliability method
基于傅立叶变换的变元可分离核函数的确定方法 |
| 2. | Fft fast fourier transformation
快速傅里叶变换 |
| 3. | Fast fourier transformation
快速傅里叶变换 |
| 4. | In the calculation of the transformation , the standard algorithms for fast fourier transformation ( fft ) can be applied to enhance the efficiency of the program
Fresnel变换是该程序的核心， fresnel变换中可以应用逆fourier变换，计算中可以利用快速傅立叶算法( fft )提高程序的执行效率。 |
| 5. | In this thesis , summarized the basic theories of fourier transformation and the fast fourier transformation that are generally adopted to detect and analyze the electric power harmonic in the electric power supply system . at the same time , summarized the even sample principle , the phenomenon of frequency mix , the window functions and the frequency leaking as so on , those are closely - related to sample from figure signal
简要阐述了电力系统谐波检测分析所普遍采用的傅利叶变换和快速傅利叶变换的基本理论以及与数字信号采样密切相关的均匀抽样定理、频谱混叠现象、窗函数和频谱泄漏等的基本理论。 |
| 6. | Summarized no - line loads and the present situations of the electric power harmonic pollution in the guangyuan district ' s electric power supply system ; explained the theories of fourier transformation and the fast fourier transformation those are widely adopted by majority scholars to examine and analyze the electric power harmonic in the electric power supply system . summarized the principle of even sample , the frequency mix phenomenon , the window functions and the frequency leaking as so on , those are closely - related to the figure signal
简要阐述了电力系统谐波检测分析所普遍采用的傅利叶变换和快速傅利叶变换的基本理论，简要阐明了与数字信号采样密切相关的均匀抽样定理、频谱混叠现象、窗函数和频谱泄漏等的基本理论，同时阐述了电力系统的谐波检测与分析的相关理论基础知识。 |
| 7. | First , a new method of ultrasound - modulated optical tomography with real - time fast fourier transformation ( fft ) is reported to improve the detection sensitivity and snr . by discriminating ultrasound modulated information carried by scattering photons , the tomographic images of the biological tissue simulating media and a buried object are reconstructed with fft spectral intensity
1 、用实时快速fourier变换( fft )和聚焦超声调制的光学层析术以增加探测灵敏度和信噪比，用fft实时地将调制光光信号滤出，用其谱强度重建图像。 |
| 8. | Based on the assumption of periodic rubbing force in rotor system , the rubbing forces onto each node of rotor system are estimated by modal expansion technique and the sub - harmonic decomposition of residual matrix between faulty and faulty - free vibration signals of rotor system through fft ( fast fourier transformation )
基于转子系统碰摩力的周期性假设，利用模态扩展方法，对故障和健康转子系统振动信号的残差矩阵进行傅立叶级数的分频谐波近似，估算得到转子轴承各节点的碰摩力。 |
| 9. | Computation method based on fast fourier transformation ( fft ) is studied deeply , whose measurement accuracy is 0 . 2s . the computing indexes involve voltage , current , power , frequency , phase , electric power , the harmonic ratio and the total harmonic distortion ( thd ) of phase voltage and phase current
深入研究了测量精度为0 . 2s级的基于快速傅立叶变换( fft )的电压、电流、功率、频率、相位、电能等电力参数和各相电压电流各次谐波含量、谐波含有率、谐波总畸变率的计算方法。 |
