查询词典 frequency channel

A new approach to eliminate the ranges dependence based on angular frequency shifting in space domain was presented, in which, the nonhomogeneity of clutter is removed and the blind area of target detection is reduced due to the fact that the clutter of all the compensated range cells in every channel is moved to the place of the clutter of the desired cell by the different angular frequency shifts being added into spatial data along all Doppler channels for every compensating range cell.

第七章针对非正侧视相控阵机载雷达，由于杂波在距离上呈现出严重的非均匀性，尤其是在近程这种依赖距离的杂波谱呈现的非均匀现象更为严重，使得用于计算自适应权的协方差矩阵不可能直接由距离单元数据统计平均来估计得到，否则STAP处理及其降维技术难以获得理想的杂波抑制性能和目标检测性能，甚至恶化。

Firstly, oscilloscope control system based on GPIB technique is presented with friendly operation environment to the HIFU system, and it uses multithreading technique in programming to realize real-time recording and display of the signal; Secondly, temperature collection and data recording system is designed, which also could get real-time recording and display of the 16 channel temperature signal, and it's believed to be of great use for further experiments of the HIFU system; Thirdly, multiple ultrasonic phased array's phase shifter is designed,which could provide 8-bit phase control in a range of frequency where the centrical frequency is 1MHZ. Fourthly, the module of serial communication is realized to insure the communication between devices and computer, including both synchronous and asynchronous communication, which enables the system to transfer data reliably and stably; Finally, the module of digital quantity control is accomplished, which provide for upper application the consistent solution to the control of exterior devices via digital interface. It can get or set the devices state using interrupt mode to receive input signal or send output signal.

主要有以下几个方面：设计了基于GPIB的示波器控制系统，给课题的研究工作提供了一个良好的环境，它采用了多线程编程的方法，能够较好的实时显示当前波形并记录数据；设计了温度采集和数据记录系统，能够对16路温度信号进行并行同步的实时采集，用于HIFU剂量学研究中温度场检测和医疗评价；设计了相控阵相位延时电路并且通过调试，满足了课题的相位控制的要求，在中心频率为1MHZ左右的频率范围内都能够达到8-bit相位控制；实现了串口通讯模块，为各项设备与计算机之间的通讯提供保证，它提供同步和异步的通讯能力，使系统能够可靠稳定的传输数据；建立了数字量控制模块，为上层应用程序提供一致的方法使用数字接口控制外部仪器，它使用中断的方式来接收输入或输出设定的开关量信号，从而得到或设定各种仪器的状态。

In order to overcome the disadvantage of volume effect and improve prospecting precision of MT, the paper puts forward a multi-channel telemetry method of stratum resistivity for linearity processing exploring depth and electromagnetic frequency in the local area, which creates a crresponding relationship between stratum resistivity and sounding line, and a multi-channel observation system is designed accordingly to explore the resistivity of underground ledge.

为克服大地电磁勘探中"体积效应"的缺点，提高探测精度，提出多道遥测地层电阻率法，该方法是在一个局部区域内，将勘探深度和电磁波周期进行线性化处理，使得地层电阻率和测深曲线建立对应关系，并据此设计了一个多道探测地下矿层电阻率的观测系统。

Output channel 3 or channel 4 of radio frequency modulator can be selected by up/down toggle switch.

射频调制器的输出频道可以通过上/下拨动开关选择3频道/4频道。

In frequency selective fading channels, different channel has different fading, that is to say, different channel has different transmission quality.

在频率选择性衰落信道中，不同的子信道受到不同的衰落，也就是说有不同的传输质量。

By time-varying filtering, we realize the signal selectivity and interference suppression, especially for the signals with time-varying power spectrum. It is shown herein that conventional eigenstructure based methods are lower dimensional special case of the time-frequency subspace fitting method. The closed-form array response estimation algorithms for blind source separation in wireless communication is also developed in the dissertation by exploiting the data structure of second-order statistics of the array output in the presence of multipath. The proposed method achieves array response estimation with little constraint on signal property and propagation environment such as scatters or angular spread. Moreover, the array utilized here can be of arbitrary geometry and even uncalibrated. Since the closed-form solution is obtained, no misconvergency may occur and large amount of computation can be saved. The equivalent feed model and corresponding optimization designation are proposed to realize the downlink multi-user selective transmission. By coherent and non-coherent superposition of the electromagnetical field, multiple beams can be formed using a single array, so that each co-channel user signal is transmitted in each beam and will not interfered with each other. The proposed system scheme implements the digital beamforming and the channel allocation in the base band, therefore is suitable for the utilization of the radio software technology. The feasibility and effectiveness of the proposed model are proved by the RF experiment.

在窄带条件下，GSC－SSF方法还可以提高阵列的虚拟孔径，从而提高估计的性能；可以证明，Cyclic DOA 和SC-SSF方法可看作该方法的特例或近似； 3、提出了二维GSC－SSF方法和宽带谱相关DOA矩阵方法，利用信号的循环平稳特性解决了宽带条件下二维 DOA 估计问题，并具有阵元数少、计算量较小的特点； 4、提出了时频子空间拟合和宽带时频DOA估计算法，将联合时频分析的理论和方法引入到阵列信号的空间谱估计研究中，利用时变滤波实现信号选择性测向和干扰抑制，特别适合于谱时变信号；可以证明传统特征结构法可看作是时频子空间拟合方法的特例； 5、提出了多用户环境下阵列响应的估计方法——CARE方法，该方法对信号结构和传播参数（主要是散射源分布与角度散布）的约束较少，适用于各种几何结构的阵列甚至未校准的阵列，能够直接得到阵列响应的闭式解，因此计算量小、稳健性好，不存在收敛问题； 6、提出了针对多用户下行选择性发送的阵列等效激励模型、优化设计方法及其系统实现方案，通过空间场的相干叠加与非相干叠加使得单一阵列能够形成多个波束，并保证各波束内的用户信号各不相同且相互干扰最小；其系统方案具有在基带实现数字波束成形、信道分配并便于软件无线电实现的特点，其有效性已得到外场实测数据的证实。

Each channel has a corresponding slot on the board with channel and frequency labeled next to it.

每个频道在槽板上都有对应的槽，清楚地标明频道号和频率。

Recent progress in radio prototype has extended the horizons of radio technology by liberating chronics dependence on hard-wired characteristics including frequency band, channel bandwidth, and channel coding. These efforts have led us to the feasibility of dynamically programmable receivers system of software radio.

软件无线电系统的硬件结构与功能相对独立，这样就可以基于相对通用的硬件平台，通过软件实现不同的通信功能，并可对工作频率、系统频带、调制方式等进行编程控制，系统的灵活性大大增加。

Pinout: C High-performance 32-bit RISC Architecture C High-density 16-bit Instruction Set C Leader in MIPS/Watt C Little-endian C Embedded ICE (In-circuit Emulation) 8-, 16- and 32-bit Read and Write Support 256K Bytes of On-chip SRAM C 32-bit Data Bus C Single-clock Cycle Access Fully Programmable External Bus Interface C Maximum External Address Space of 64M Bytes C Up to Eight Chip Selects C Software Programmable 8/16-bit External Data Bus Eight-level Priority, Individually Maskable, Vectored Interrupt Controller C Four External Interrupts, including a High-priority, Low-latency Interrupt Request 32 Programmable I/O Lines Three-channel 16-bit Timer/Counter C Three External Clock Inputs C Two Multi-purpose I/O Pins per Channel Two USARTs C Two Dedicated Peripheral Data Controller Channels per USART Programmable Watchdog Timer Advanced Power-saving Features C CPU and Peripheral Can be Deactivated Individually Fully Static Operation: C 0 Hz to 75 MHz Internal Frequency Range at VDDCORE = 1.8V, 85C 2.7V to 3.6V I/O Operating Range 1.65V to 1.95V Core Operating Range -40C to +85C Temperature Range Available in 100-lead TQFP Package

M5L8253P-5引脚说明： C型高性能32位RISC架构C高密度以MIPS /瓦C小端C十六位指令集C领袖嵌入式冰8 - 16 -位和32位的读写支持256K的片上SRAM的 32位数据总线C单时钟周期存取字节完全可编程的外部总线接口C最大的外部地址空间的64M字节多达8个C芯片选择C软件可编程8位外部数据总线8级优先级，独立可屏蔽，向量中断控制器C四外部中断，其中包括一个高优先级，低延迟中断要求32个可编程I / O口线三通道16位定时器/计数器C三个外部时钟输入C两多用途I / O引脚每通道2个通用同步C两专用外设数据控制器通道每个USART可编程看门狗定时器先进的节能特性 CPU和外设可停用独立全静态工作中：C 0 Hz至75 MHz的频率范围内的VDDCORE = 1.8，85℃2.7V到3.6VI / O的操作1.65V到1.95V范围核心工作电压范围在- 40C至+85 C温度范围内使用的100引脚TQFP封装

In the range frequency and compressed azimuth time domain of Tri-channel SAR/GMTI data, the clutter is cancelled by the mutual channel, and the PRF ambiguity number can be estimated from the remaining signals.

首先将三通道SAR/GMTI数据在方位压缩后的距离频域两两对消抑制杂波，然后进行PRF模糊数估计。

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。