查询词典 frequency channel

At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.

一种DFT扩频的广义多载波系统的SINR估计方法，其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系，然后根据信道频率响应、信道噪声方差和均衡方法，设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数，再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差，再计算有效信干噪比，如此以实现对广义多载波传输系统的有效信干噪比的准确计算，该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。

When the digitalsignal carries on the long distance transmission, the high frequencycomponent weaken increases along with the distance increases, theelectric cable median line also advances to the betweenelectromagnetic radiation along with the frequency intensifies, thusthe clipped wave transmitting range and the transmission quality,simultaneously in the channel often also exists separates the directcurrent electric capacity and the coupling transformer, they cannottransmit the direct component and have a bigger weaken to the lowfrequency component, therefore high frequency and low frequency arepartial regarding the common channel is limited.

当数字信号进行长距离传输时，高频分量的衰减随距离的增大而增大，电缆中线对之间的电磁辐射也随着频率的增高而加剧，从而限制信号的传输距离和传输质量，同时信道中往往还存在隔直流电容和耦合变压器，他们不能传输直流分量及对低频分量有较大的衰减，因此对于一般信道高频和低频部分均是受限的。

The proposed algorithm can deal with Carrier Frequency Offset and Sampling Frequency Offset estimation with the presence of frequency dependent In-phase and Quadrature-phased imbalance. Then frequency dependent I/Q imbalance and channel response are jointly estimated.

该联合估计算法能在存在频率相关性I/Q失配的情形下准确获得载波频率偏差和采样频率偏差的估计，并获得频率相关性I/Q失配和信道冲击响应的联合估计信息。

Simulation results show that, for the fixed sampling frequency, the error rises with the frequency increasing of periodic signal, and decreases with the attenuation time constant increasing of non-periodic signal. The sampling frequency determines the upper limit of appropriate frequency band directly. The research provides the basis for the selection of cutoff frequency in filter design.

仿真结果表明，在采样频率确定时，对于周期信号，计算误差随频率的增加而增大，而对于非周期信号，计算误差随衰减时间常数的增大而减小，采样频率大小决定了插值法用于分布参数模型的适用频带上限，该研究为滤波器设计中截止频率的选择提供了依据。

This experiment is in frequency adjustment X-mitter about that miniwatt frequency adjustment X-mitter operating principle, analyses the debugging making method and their installation, the microphone changes implication into an audible signal, wave an audible signal being modulated as a result of enlarging the day afer tomorrow being in progress to the carrier wave , producing frequency adjustment, by the fact that air wire launching the frequency adjustment electromagnetic wave to the outside , the radio set just can with frequency adjustment meet hear clear implication.

本毕业设计是关于小功率调频发射机工作原理、分析制作方法及其安装调试，在调频发射机中，话筒将话音转化为音频信号，音频信号经放大后对载波进行调制，产生调频波，通过天线向外发射调频电磁波，用调频收音机便可以接听到清楚的话音。

Two common methods of GPS signal coarse acquisition are analyzed and compared in this paper, and an optimized method is adopted. Two common algorithms of calculating fine frequency are analyzed and compared and the conics fitting is designed to calculate the fine frequency. Based on the distributing character of Doppler frequency shift, swing frequency style of Doppler frequency shift search is employed.

对比分析了两种常用的GPS信号粗捕获实现方法，设计了一种优化的实现方法；同时对常用的两种精细载波频率算法进行了比较分析，设计了一种二次曲线拟合的方法计算精细载波频率；基于多普勒频移的分布特点，改变以往顺序搜索的方式，采用跳频搜索的方法。

The traditional analog frequency-sweeping instrument, which mostly uses the LC circuit as the frequency oscillator, is more expensive, too much bigger and heavy to carry. It can only display the curve of amplitude-frequency, but can't used to measure the phase-frequency, and can't used to print the curve of frequency response characteristic either. It brings many discommodity to the user.

传统的模拟式扫频仪大多是用LC电路构成扫频振荡器，它不仅价格昂贵，体积庞大，而且只能显示幅频特性曲线，不能得到相频特性曲线，更不能打印被测网络的频响曲线，给使用者带来诸多不便。

The time-domain response of the induced currents on a scattering object irradiated by a plane wave with a Gaussian pulse in time is expanded as an associate Hermite series in this paper. Using the isomorphism of the associate Hermite function and its Fourier transform, the frequency-domain information can be obtained similarly to the time-domain expansion. According to the corresponding relation between time-domain analysis and frequency-domain analysis, and using the early-time response and the low-frequency information of the induced currents, the non-known coefficients in the expansion series can be decided. The entire responses of the induced currents on the scattering object in both time and frequency domains can be obtained at one time by simultaneous extrapolation computation using both the early-time response and the low-frequency information of the induced currents.

摘要首先根据散射体在高斯脉冲平面波激励下感应电流的能量几乎全部集中在时间轴和频率轴上的有限范围内，该文将时域响应展开为系数待定的连带Hermite级数的叠加，并根据连带Hermite函数的傅里叶变换的自反性，得到与时域响应形式类似的频域响应；然后利用时域方法和频域方法分别计算散射体上感应电流的早时响应和低频信息；最后经过时域和频域联合外推计算，由早时响应和低频信息确定时域和频域响应的待定系数，从而获得了整个时域和频域的完全响应。

A CPU over-frequency method and system is composed of CPU, set module with BIOS ROM and CMOS RAM, control module of peripheral unit, storage module and time clock generation module. CPU over-frquency processing is completed automatically by executing CPU over-frequency program stored in BIOS ROM, meanwhile the highest FSB frequency value of CPU is obtained, and the system and peripheral unit can run at it. A testing for system stability is added to process of CPU over-frequency processing in order to ensure that the FSB frequency is applicable to the operation of CPU and peripheral unit.

一种CPU超频方法以及系统，包括CPU、具BIOS ROM及CMOSRAM的设定模块、外围装置控制模块、存贮器模块以及时钟产生模块组成，经过执行储存于BIOS ROM中的CPU超频程序后，自动完成CPU超频处理，并取得可供系统与外围装置稳定运作的最高的CPU的FSB频率值，于CPU超频处理的过程中，自动加入系统稳定性的测试，确保该FSB频率值适用于CPU与外围装置运作，使系统运作在超频状态下，亦能稳定地工作。

This paper analyzes the principle of chief anti jamming technologies of frequency agile radar FAR frequency diversity radar FDR and self adapt frequency agile radar SAFAR in frequency domain studies the effectiveness measurement methods of these technologies brings forward the self adapt improvement factor which measuring the anti jamming effectiveness of self adapted frequency agile radar .

分析了频率捷变，频率分集，自适应频率捷变等雷达在频域的主要抗干扰技术原理，研究了这些技术的效果度量方法，提出了度量自适应频率捷变雷达抗干扰效果的自适应改善因子。

Article 144 The Government of the Hong Kong Special Administrative Region shall maintain the policy previously practised in Hong Kong in respect of subventions for non-governmental organizations in fields such as education, medicine and health, culture, art, recreation, sports, social welfare and social

第一百四十四条香港特别行政区政府保持原在香港实行的对教育、医疗卫生、文化、艺术、康乐、体育、社会福利、社会工作等方面的民间团体机构的资助政策。原在香港各资助机构任职的人员均可根据原有制度继续受聘。

Small wonder, then, that the Chinese spend more in the shop than any other group of foreign visitors do .

这样的小惊喜，使中国顾客比任何国家的人消费得更多。