| 1. | Choose the frequency from 14 to 16 bark as the embedding positions which below the masking threshold . then change the dct coefficient with the certain strength of
选用中低频14 16bark段在掩蔽阈值以下的频率分量作为嵌入点,对该嵌入点的dct系数以一定嵌入强度作修改来实现秘密信息的嵌入。 |
| 2. | This dissertation put forward a method of eliminating noise and reconstituting broken wires signal and inquired the space - frequency range of the signal ripple resulted from tensile stress on the mfl signal curve
提出了去除干扰重组断丝信号的方法，分析了漏磁曲线上应力波纹的空间频率分量。 |
| 3. | Fourier transform method use high order frequency to analyse and imitate nonlinear and non - stationary data . emd method based on local characteristic time scale of the data is more fit to analyse nonlinear and non - stationary data than fourier transform method
Emd基于信号的局部时间特征尺度分析原信号，克服了傅里叶变换用高次谐波频率分量拟合非线性、非平稳信号的缺点。 |
| 4. | In order to avoid spectrum error due to energy leakage , the thesis research on identification of parameters of two close frequency components in discrete spectrum analysis , and simulation result shows the validity of the method
针对由于能量泄漏造成的频谱误差，深入研究了密集频谱的频域参数识别法，从理论上加以推导，并通过仿真证明了该方法的有效性，可以识别1个频率分辨率以内的两临近频率分量。 |
| 5. | So the pipe system sends out noise because of resonance . especially the frequency 250hz of pulsating water is in close proximity to natural frequency of pipe , so the 250hz is a dangerous frequency to the pipe system . there is another reason why the noise is reached to 110db ( a ) in pump room that the noise is magnified by the cistern because of the resonance of cistern
特别是激励频率为250hz的频率分量恰好与管道系统的固有频率相接近，其引起的管道振动对噪声的贡献最突出，同时也与水泵房房腔的固有频率相接近，从而引起房腔共鸣发声，使噪声进一步被放大，以至于噪声最大处高达105db ( a ) 。 |
| 6. | And then the stability and the stable error response of the dpll are analyzed . there is an obvious doppler shift frequency offset in the received signal with flight at a high speed , in the dissertation the uniform sampling second - order dpll is used to remove the frequency bias for its excellent high - pass characteristic of the error transfer function
由于高速飞行的遥测目标在接收信号中会出现较大的多普勒频率分量,而典型均匀采样二阶数字锁相环dpll ( digitalphase - lockedloop )的误差函数具有高通特性,所以本文提出一种利用其高通特性来去除多普勒频率分量的新方法。 |
| 7. | Then the paper presents two important concepts on wavelet transform : multi - resolution analysis and wavelet package analysis . last , the paper introduces the application of wavelet transform on power quality analysis , especially on the research of voltage flicker . we can get the magnitude and frequency of the embed signal by mra
最后介绍了小波变换在电能质量分析中的应用，重点讨论了电压闪变问题，用小波多分辨率分解和子带滤波方法对电压闪变的包络信号进行分解，检测出包络信号中的各个频率分量及其幅度。 |
| 8. | Based on frequency - spectrum - transformation , this algorithm first changes acceleration spectrum into displacement spectrum , then calculates its amplitude , angular frequency and initial angle related to every displacement spectrum , finally sums up all the displacement components and forms the time course of the measured vibration
该方法采用频谱转换法，首先将加速度谱转换成位移谱，再计算出位移谱中每个频率分量对应的幅值、圆频率和初相角，最后对各位移分量进行叠加得到振动位移的时间历程。 |
| 9. | The spectrum analysis showed that only the balance signals require processing by digital filter , and only inherent frequency components of balance , bracket and model system of the balance signals will require filtering , but the resonance components of test force oscillatory are . saved as more as possible
数据的频谱分析结果表明只须对天平测量信号做数字滤波处理；滤波原则是仅需滤掉天平、支架、模型系统的固有振动频率分量，同时尽可能多地保留实验强迫振动的各阶谐振信号。 |
| 10. | Chapter 3 : we find a family of solutions of the paraxial wave equation that represents ultrashort pulsed light beams propagation in free space . these pulsed beams have an arbitrary temporal form and a nearly elegant hermite - gaussian cross section , which pulsed beams we call the ultralshort pulsed elegant hermite - gaussian beams
此脉冲光束解的每个频率分量都是eleganthermite - gaussain光束，时间脉冲的形状是任意的，具有相同的衍射距离参数，并且可以描述短于一个光学周期的超短脉冲。 |
