频率调制

Therefore, it has significance to optimize the demodulation curve. By the use of expansion of Bessel function and optical field overlapping method, the relation between the demodulation curve and the resonant frequency deviation was analyzed.

利用贝塞尔函数展开和光波场叠加的方法分析了谐振式光纤陀螺调相检测系统解调输出信号与谐振频率偏差之间的关系，系统采用的是带有铌酸锂相位调制器的相位谱检测技术。

The impact of the thickness of volume H-PDLC grating on the wavelength selectivity of Bragg diffraction are simulated numerically, as well as the theoretic relationships among the refractive index modulation, spatial frequency and the H-PDLC diffraction efficiency.

计算机模拟了体光栅厚度对于布拉格衍射波长选择性的影响，以及折射率调制深度、空间频率和H-PDLC光栅衍射效率的关系。

In communications, the frequency range of the information bearing signals prior to combination with carrier wave by modulation.

在通信技术中，未经调制使之和载波结合之前，携带信息的信号所占有的频率范围。

The experimental results show that it achieves peak SNR of 80 dB, peak SNDR of 78 dB and dynamic range of 84 dB over a 1 MHz signal band-width when clocked at 128 MHz. It dissipates 9 mW from a 1.8 V supply.

芯片工作在1.8V电源电压和128MHz时钟频率，在1MHz的信号带宽内，调制器的动态范围为84dB，峰值SNR和SNDR分别为80dB和78dB，功耗为9mW。

For the bottom-up attention process, areas of interest that deserve visual attention are formed by a sequentially extracting of feature map, conspicuity map, and interesting map. Firstly, based on Treisman's feature integration theory and the characteristics of orientation and frequency selective nerve cells in biological cortex, we propose a new 2D optimal quadrature filter in the meaning of minimum energy loss to extract intensity, edge, orientation, symmetry, curvature and comer features to form the feature maps. Then based on the local competent and global cooperative perception character of biological vision, we design a kind of competent/cooperative filter and use a set of such filters to extract conspicuous locations that will most likely to cause visual attention from feature maps to form conspicuity maps.

我们根据Treisman〓的特征整合理论，结合生物视觉皮层的方向、频率敏感性神经元，提出采用一组调制在不同尺度和方向上的新的最佳正交特征滤波器并行地提取图象的亮度、边缘、方向、对称性、曲率和角度等特征作为注意线索，构成特征图；在此基础上，基于生物视觉的局部竞争和全局协作特性，本文设计了一种竞争协作滤波器用于从特征图中提取可能引起视觉注意的显著位置构成显著图，各显著图进一步通过本文提出的融合算法和非线性松弛迭代算法生成自底向上兴趣图。

This opens the possibility of a new type of cross modulation, where a beam of light at one of the absorption frequencies can turn on or off the light of the other.

这就可能制造出新型的交叉调制器，一束有特定吸收频率的激光能打开或关闭其它的光。

Based on the second-order statistics, cyclic autocorrelation function , a method of demodulation is deduced.

推导了二阶循环统计量——循环自相关函数的解调方法，该方法通过搜索循环频率而将调制源分离在循环域的低频段，并且调幅和调频信号有不同的解调结果。

This paper analyzes the frequency characteristics of comb filter and the principle of using comb filter as decimation filter.

文章分析了梳状滤波器的频率特性及其作为抽取滤波器的原理，特别指出了此种滤波器具有对Σ－△调制器成型的量化噪声的频谱形状保持不变的特性。

The output of electron acoustic signal in the ferroelectrics is calculated on the basis of their piezoelectric properties. The results show that the magnitude of electron acoustic signal not only related with beam currents, beam power and modulation frequency, but also with sample properties especially electric parameters such as dielectric constant and spontaneous polarization.

本文首次以典型的铁电BaTiO〓材料为试样，从其具有的压电性出发，推导了这类材料的电声信号理论表达式，结果表明电声信号的大小不仅与实验参数如入射电流、入射电子能量以及调制频率等有关。

So using fractal theory box dimension and information dimension can be extracted from signal as the classification feature.

因此利用分形理论从信号中提取盒维数和信息维数作为分类特征，这种特征可包含信号幅度、频率和相位的变化规律，并集中了不同调制信号之间的差异信息。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。