查询词典 frequency band

The tunable photon broad band radio frequency phaser based on a silicon ring resonance cavity comprises a pumping signal light-generating system, a carrier wave light-restraining double-sideband generating system, a silicon ring resonance system and a measuring system; wherein, the silicon ring resonance system comprises a light coupling device and the silicon ring resonance cavity; the output of the light coupling device is connected with the input port of the silicon ring resonance cavity; wherein, the silicon ring resonance cavity is composed of a silicon annulet and a root of a straight waveguide; the air gap distance between the silicon annulet and the root of the straight waveguide is several ten nanometers or several hundred nanometers; the taking characteristic of the silicon ring resonance cavity is the characteristic of a seasonal reject trap; the transmission rate in the position of a resonance wavelength is equal to zero or is very close to zero.

本发明包括：泵浦信号光发生系统、载波抑制光双边带产生系统，硅基环形谐振腔系统，以及测量系统。所述硅基环形谐振腔系统包括一个光耦合器和一个硅基环形谐振腔，光耦合器的输出连接到硅基环形谐振腔的输入端口，其中：硅基环形谐振腔由一个硅基微环和一根直波导构成，硅基微环和一根直波导之间的空气隙间隔为几十至几百纳米，硅基环形谐振腔频谱特征是周期性的带阻滤波特性，在谐振波长处的透射率等于0或非常接近0。

First of all, the circuit output waveform in the case of losing it by measuring the input voltage and output voltage in order to detect amplification of analog circuits, and then by adjusting the frequency of AC voltage source to reduce the output gain make 3db analog circuits in order to measure the maximum cut-off frequency, pass band can be obtained.

本电路首先在输出波形不失真的情况下通过测量输入电压和输出电压从而测出模拟电路的放大倍数，然后通过调节交流电压源的频率使得输出增益减少3db从而测量出模拟电路的上限截止频率，即可求出通频带。

Some methods, in which synthesized theoretical seismogram of high frequency is taken as record signal and 20%random noise is superimposed on the seismogram, are used to analyze the theoretical seismogram. The digital experiment shows that in the correlating frequency range, Green's function method can measure precisely interstation phase velocity, but the results obtained by correlation and narrow band-pass filtering correlation methods are more dispersed.

以合成的高频理论地震图作为记录信号，并在理论地震图上叠加了20％的随机噪声，利用这些方法分析理论信号，数字实验表明：在相干频率范围内，格林函数方法能够精确测量台间相速度，而互相关法和窄带通滤波互相关法所得结果较为离散。

Photonic quantum-well structures can be constructed by stacking 3 photonic crystals with the same photonic band gap and different defect modes. On condition that the defect mode of the PC in the well region is located into nontransmission frequency ranges of the PCs in the barrier regions, the confined photonic state appears and can completely transmit through the structure by tunneling. However, its transmission will be strongly prohibited due to vanishing of the photonic QW induced by shifting the defect mode frequency of either of the PCs in the surrounded regions to that of the middle PC.

把三块各带有一个缺陷的光子晶体结合起来，如果中央晶体的缺陷模处在两侧晶体的禁带中，缺陷模内的光波会受到两侧晶体的阻碍并被局域在中央晶体内，形成量子阱结构；若一侧晶体的缺陷模被移动到中央晶体缺陷模处，则只有一侧晶体阻碍在中央晶体缺陷模内传播的光波，量子阱效应完全消失，光的传输受到最大程度的阻碍。

The frequency response transformation from a lowpass to a band pass filter is given, the change of the filter susceptance with frequency being taken into account.

给出了低通到带通的频响变换式，这个变换式考虑了滤波器电纳随频率改变。

In order to eliminate the aliasing, at each step of decomposition or reconstruction, fast Fourier transform is performed the result obtained by convolving the input signal with filters, setting frequency spectrum of the redunctant frequency components to be zero, and inversely fast Fourier transforms the result after zeroing. The result after processing is the input signal of next step,and single sub-band reconstruction is implemented to extract the feature item of GPS data sequence.

为消除频率混淆现象，分解与重构时，每作一次信号与小波卷积后，将其结果作一次快速傅立叶变换，频谱中多余的频率成分的谱值置零，再对置零后的频谱进行傅立叶逆变换，然后继续进行小波包的分解与重构，从而实现单子带重构提取GPS数据序列特征项。

According this problem, firstly this paper delves into radio circumstance of the band, frequency selecting rule and spectral density estimation. Basing on this research, this paper puts forward a frequency selection scheme basing on estimating spectral density of channels in 2.4GHz~2.5GHz.

针对此问题，本文首先深入研究了该频段无线电环境、选频准则及功率谱估计理论，在此基础上提出一种基于信道功率谱估计的选频方案。

It is very difficult to realize expanding the working band of Hartmann-Shack wavefront sensor through Frequency Transfer of Nonlinear Optics. Usually three wave-mixing researches are based on plane wave or Gauss wave, so study of aberrated second harmonic generation is new and important. It could be very helpful to understand and make good use of the Frequency Transfer of Nonlinear Optics.

这说明利用非线性光学频率变换方法拓宽波前传感器件的响应波段是很难实现的，但是，通常三波相互作用过程的研究均是建立在平面波和理想高斯光束之上，因此我们对于位相畸变倍频过程的研究是非线性光学领域一个重要而有意义的新课题，它有助于人们更加深入理解非线性光学效应，为进一步合理利用之奠定了理论和实验的基础。

In this paper, for the first time, the impact of the noise frequency-modulated signal to a wide band linear frequency modulation matched filter is studied for different modulation noise variance and bandwidth.

研究了噪声调频信号中调制噪声方差及带宽的选择对宽带线性调频匹配滤波器的影响。

Based on these design guides, the analysis and design of a low phase noise and low power dissipation, with 0. 18μm CMOS process, integrated Colpitts crystal oscillator with automatic gain controlled feedback loop as the amplitude-limiting technique, low dropout voltage regulation with band gap reference voltage and frequency tuning monotonicity guaranteed by digitally controlled variable capacitor array is performed to revise influence caused by process, voltage and temperature conditions for. handset. The oscillation with very stable amplitude value and frequency value is achieved.

它利用对工作温度、电源电压和制造工艺不敏感的带隙基准源和在集成电路中元件特性之间匹配好的优点产生了一个不随温度、电源和工艺改变而且可以跟踪工艺变化的参考基准电压，同时通过自动频率控制环路利用数字电路控制可变电容阵列控制瞬态频率稳定度，校正温度、电源和工艺改变对频率的影响，从而可以在很宽的电源电压范围(2.7v—3.7v)和温度范围(-40℃—125℃)以及CMOS工艺参数变化(TT、FF、SS、SF、FS)的条件下提供幅度稳定、频率稳定的振荡输出信号。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。