查询词典 frequency channel

Begin from the chapter three, this text expound the fact of the algorithms that the channel estimation mainly, first of all, this text has been introduced and the important function of the channel estimation algorithm of Orthogonal Frequency Division Multiplexing ,on this basis, this text Introduce the detailed introduction of the channel estimation algorithm, also essentialing structure.

从第三章开始，本文主要论述了信道估计的算法。

Using two channel tree-structured filter banks, an image can be decomposed into a pyramid structure, with various band information: such as low-low frequency band, low-high frequency band, high-high frequency band etc.

小波分析是一种时间-尺度分析方法，可被看作傅立叶变换之后又一里程碑式的发展，是近年来迅速发展起来的新兴学科，小波变换应用于图像处理的基本思想就是把图像进行多尺度、空间-频率分解。

So it holds a ideal ability to anti-interference and has 2 scalar level resolution in location and measuring velocity than traditional radio induction technology. And the channel composed of the new radio induction system for communication is different from the parameter-constant channel and the traditional parameter-changing channel, its parameter is decided by the mutual induction between its antenna and induction-cable, by the location of its antenna, by the signal frequency passing through, its parameter has nothing to do with the time parameter.

而且，由新型无线感应系统组成的信道既不是恒参信道，也不是一般目前所知的变参信道，其信道传递函数的幅值只与信号的频率有关，与系统中天线和感应电缆之间的互感和天线的位置有关，而与时间无关，其信道传递函数的相位只与天线的位置有关，而与时间无关，由新型无线感应系统组成的信道是一种不随时间变化的新型变参信道。

Its software uses system self-detecting algorithm to assure measurement channel .It uses softening hardware technique software synchronic data sampling to trace the frequency of exterior signal, in other words , it gives sampling control signals 128 times of power net's frequency .It uses Direct Digital Frequency Synthetics algorithm to transform radical sine waveform parameter table into needed current. It uses FFT algorithm to get radical waveform altitude of current ,voltage and resistor .

整个系统在软件设计上采用系统自检验算法保证测量通道可用，采用硬件软化技术--软件锁相环技术，达到对外部信号频率的跟踪，给出频率为电网工频128倍的采样控制信号：直接数字频率合成技术将基波参数表转换成需要的电流信号，采用FFT变换及基波幅度的计算方法得到被测电流、电压基波幅度和电阻大小。

The method includes following steps:(1) initial frequency selection;(2) based on modulation mode adopted, the sending end carries out symbol mapping, changes signal spectrum based on label information of sub channel, and sends signal in time domain;(3) based on label information of sub channel, the receiving end carries out equalization for received signal, demodulates signal and accomplishes judgment;(4) carrying out channel estimation or prediction, the receiving end obtains updated information of signal state, and determines whether label information of sub channel is needed to update based on self-adapting judgment rule.

本发明提供了一种移动宽带信道中的自适应选频分块传输方法，该方法包括以下步骤：(1)初始选频；(2)发端根据所采用的调制方式进行符号映射，根据子信道标记信息改变信号频谱，并发送时域信号；(3)收端根据子信道标记信息对接收信号进行均衡，解调信号并完成判决；(4)收端进行信道估计或预测得到更新的信道状态信息，根据自适应判断规则，判断是否需要更新子信道标记信息。

The realization monolithic integrated circuit system double audio frequency, this radio has used double audio frequency decoding chip MT8870, demodulates the tonic train signalling from the frequency-modulated signal, and separates the double tonic train signalling from the tonic train signalling to enter the double audio frequency decoding electric circuit implementation letter command to decode, thus carries on the low gear rate using the frequency modulation channel the control command transmission.

为实现单片机控制的双音频解码，本收音机采用了双音频译码芯片MT8870，从调频信号中解调出音频信号，并从音频信号中分离出双音频信号进入双音频解码电路实行信令解码，从而利用调频信道进行低速率的控制指令的传输。

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。

The paper investigates both block-type pilot linear minimum mean square error algorithm and IEEE802.16 OFDM channel estimation analysis. Simulation results confirm the block-type pilot structure is more suitable for IEEE802.16 system. An optimal pilot setting algorithm, based on space frequency domain, is explored and the pilot chart is presented. The proposed algorithm finds its application in MIMO-OFDM. Simulation results show the algorithm presents a good approximation to the perfect channel state information curve, with about 2dB difference in SNR. The simulation results also demonstrate the algorithm achieves fairly high stability in the environment of fast fading, performance of the proposed algorithm is better that of pilot training channel estimation.3. Taking into account the characteristics of IEEE802.16 OFDM system, OFDM system simulation platform is constructed in Matlab, exploiting simulink as a tool. OFDM modulation and demodulation simulation system are configured on LabVIEW platform. All the system signal processing is simulated, including defining system parameters, designing modulation model, and verifying all the proposed algorithms under different environments, such as white Gaussian noise, multi-path fading, with or without guard interval etc. Bit error performance is evaluated. The research provides valid theoretical basis for practical OFDM system performance evaluation.4. Taking advantage of software radio, the paper designs a hardware platform with both 256-IFFT/FFT and 512-IFFT/FFT OFDM schemes co-existing in one platform. You can predetermine one from the two schemes to carry out almost the same model function with different system performance and parameter setting.5. Referring to IEEE802.16 standard, the paper proposes a design method for generating signals and frames suitable for laboratory investigations implemented in laboratory environment.6. Based on 6701evm digital evaluation card, combined with analogy front-end, the paper designs a DSP software model to deal with baseband signal processing. An overall OFDM scheme, with modulation and demodulation function, is accomplished.

讨论分析了MIMO-OFDM中一种基于空频域的最优导频设置算法，给出了导频图案，通过仿真实验表明，该算法与理想的信道状态信息曲线非常接近，信噪比差距约在2dB左右，并且在快衰落条件下具有较好的稳定性，其性能要优于基于前导训练的信道估计方法。3、根据IEEE802.16OFDM系统特点，论文分别在Matlab中应用Simulink工具构建OFDM系统仿真平台、在LabVIEW平台上实现了OFDM调制解调仿真系统，模拟了整个系统的信号流程，进行了OFDM仿真系统参数的选择和调制模块的仿真设计、论证各算法性能，并根据各种不同的条件：例如高斯噪声、多径衰落、有无保护间隔等，对系统的误码特性进行了评估，为正确评价实际OFDM系统的性能提供了有效的理论依据。4、论文以软件无线电思想作为指导，提出了以256点IFFT／FFT为核心和以512点IFFT／FFT为核心的两种OFDM算法模式并存于同一个硬件平台、且可预选的方案，它们在参数选取和性能指标上有所差异，均实现了相似的模块和功能。5、论文参考IEEE 802.16无线网络标准的参数设置，针对本设计系统的应用环境和系统硬件的性能速率，提出了一种应用于实验室环境的信号结构、帧格式等参数设计。6、论文基于TI公司的6701evm数字评估板卡，结合模拟前端搭建数字中频平台，设计了基带处理的DSP软件模块并进行系统调试，基本实现了一套完整的OFDM调制解调方案。

In addition, since the channel frequency response is usually oversampled by the pilot sub-carriers, the channel power will be concentrated to a relatively small number of samples in the effective channel impulse response vector.

这种情况下，如果在进行基于DFT的内插之前，我们不用一个窗函数对观测到的信道频率响应向量进行加窗处理，则内插后，由能量泄漏而引起的混叠现象将导致信道估计的错误平底。

Consequently the beam transmission problem is solved well. The general design curves of microwave plasma drift tube are developed by the theory and they can be used for development of the plasma microwave devices. Ion channel, as a important phenomenon in the interaction between electron beam and plasma, is first introduced into the study of PASOTRON, to replace the concept'plasma channel'used in general plasma microwave devices. A model is created to describe the channel performance. The channel is not stable, it is oscillatory and the oscillation frequency is larger than that of plasma.

作为电子束与等离子体相互作用的一个重要现象，本文首次将离子通道的概念引入到了PASOTRON的研究中，以区别常规的等离子体通道概念，并通过建立的模型推出离子通道并非一稳定规则的通道，而是具有振荡特性，振荡频率高于等离子体频率，推出了当满足一定条件时束外可能没有电子而成为纯的离子通道，这种状态对微波器件有重要的价值。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。