Description: labview 数字电压表 功能描述：实现仿真信号的电压测量，显示信号频率、标准频率、相位、幅值、直流偏置、峰值、平均值和有效值，并以图形方式显示仿真信号。-labview digital voltmeter Description: Implementation of the simulated signal voltage measurement, display the signal frequency, standard frequency, phase, amplitude, DC offset, peak, average and RMS, and graphically display the simulation signal. Platform: |
Size: 438272 |
Author:zheng yue |
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Description: 参考Matlab提供的模块建立简化的三相锁相环的仿真模型，只保留必要的步骤，如abc-dqz只计算Vq，去除频率反馈模块和自动参数调整模块等。
建立单相锁相环的计算模型
简化单相锁相环的系统结构，保留必要的PI控制器等模块
验证并讨论输入信号频率在45-65Hz变化时设计的锁相环的动静态性能
仿真并分析三相输入信号包含谐波、不平衡和直流偏移时锁相环的锁相结果-Reference Matlab provides three-phase PLL module to establish a simplified simulation model, retaining only the necessary steps, such as abc-dqz counting only Vq, remove frequency feedback module and automatic parameter adjustment module. simulation and analysis of the three-phase input signal contains harmonics, unbalance and DC offset PLL phase-locked Results Platform: |
Size: 305152 |
Author:李航 |
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Description: tf–idf, short for term frequency–inverse document frequency, is a numerical statistic that is intended to reflect how important a word is to a document in a collection or corpus.[1]:8 It is often used as a weighting factor in information retrieval and text mining. The tf-idf value increases proportionally to the number of times a word appears in the document, but is offset by the frequency of the word in the corpus, which helps to control for the fact that some words are generally more common than others.
Variations of the tf–idf weighting scheme are often used by search engines as a central tool in scoring and ranking a document s relevance given a user query. tf–idf can be successfully used for stop-words filtering in various subject fields including text summarization and classification.
One of the simplest ranking functions is computed by summing the tf–idf for each query term many more sophisticated ranking functions are variants of this simple model.-tf–idf, short for term frequency–inverse document frequency, is a numerical statistic that is intended to reflect how important a word is to a document in a collection or corpus.[1]:8 It is often used as a weighting factor in information retrieval and text mining. The tf-idf value increases proportionally to the number of times a word appears in the document, but is offset by the frequency of the word in the corpus, which helps to control for the fact that some words are generally more common than others.
Variations of the tf–idf weighting scheme are often used by search engines as a central tool in scoring and ranking a document s relevance given a user query. tf–idf can be successfully used for stop-words filtering in various subject fields including text summarization and classification.
One of the simplest ranking functions is computed by summing the tf–idf for each query term many more sophisticated ranking functions are variants of this simple model. Platform: |
Size: 17408 |
Author:adel |
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Description: 正交频分复用的基本仿真系统，供初学者参考，包含频偏等基本参量的设置-Orthogonal Frequency Division Multiplexing basic simulation system, the reference for beginners, including offset and other basic parameters set Platform: |
Size: 2048 |
Author:qf |
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Description: 对于城市环境中的高精度单频 GNSS 接收机而言，若考虑误差预报处理已抵消电离层误差，则地面传播环境所导致的多径效应将成为系统误差的主要因素。基于现有蜂窝通信的高分辨率信道估计结果，针对电波传播的幅度、相位、多普勒等特征提取信道响应函数，在极小误差范围内提供至 L 波段信号的线性特征映射-For multipath effects in urban environments with high accuracy single-frequency GNSS receiver, the forecast error handling when considering the ionosphere has been offset error, the ground caused by the propagation environment will be a major factor in system errors. High-resolution channel estimation based on the results of existing cellular communications, the channel response function for extracting the magnitude of wave propagation, phase, Doppler and other features, provided to the L-band signals in a very small error range of linear feature mapping Platform: |
Size: 345088 |
Author:杨佳琳 |
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Description: 用相位移加实现速度纵横向变化、复杂陡倾地质模型的正流模拟，为复杂波场的地震、地质解释提供了精确、实用的方法。一般情况下，相位移延拓方法对徒倾斜地层成像精度高、稳定性好、计算快，但实现速度的横向变化困难；而频率、空间域的有限差分法算法简单、稳定性好、能适应速度的纵横向任意变化，但偏移陡断地层存在很多问题-Using phase shift and realization of vertical velocity variations, complex flow simulation of steep dip geological model, seismic and geological interpretation of complex wave field provides accurate and practical way. Under normal circumstances, phase displacement extrapolation method for imaging of tilted strata of high precision, stability, quick calculation, but difficulties of lateral velocity variations, and frequency and spatial domain algorithm of finite difference methods for simple, good stability, can adapt to the speed of longitudinal and lateral variation, but offset steep faulted strata there are many problems Platform: |
Size: 33792 |
Author:肖青松 |
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Description: Analysis of Carrier Frequency Selective Offset Estimation - Using Zero-IF and ZCZIn MC-DS-CDMA-Analysis of Carrier Frequency Selective Offset Estimation- Using Zero-IF and ZCZIn MC-DS-CDMA Platform: |
Size: 559104 |
Author:li |
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Description: WIMAX_WZ_withencoding:信道估计，相位噪声补偿，频偏估计，编解码都有
WIMAX_WZ_withoutencoding：在上面的工程基础上，去掉编解码部分
WIMAX_WZ_withoutprocessing：在上面的工程基础上，再去掉相位噪声补偿，频偏估计
WIMAX_WZ_withoutprocessing2：在上面的工程基础上，改用新的前导和导频联合信道估计方案,参考文档《基于802_16d标准的OFDM信道估计技术的研究与实现.kdh》
因为白噪声信道仿真只能体现QPSK调制和RS-CC编码的性能，需要仿真SNR可控的SUI信道，来估计信道均衡的性能。
在多普勒频偏fd>100Hz时，联合信道估计性能才比前导估计强，否则前导估计性能更优。对于600MHz中心频率，要求收发机相对运动速度大于180km/h，这种情况出现的概率不大-WIMAX_WZ_withencoding: channel estimation, phase noise compensation, frequency estimation, the codec has WIMAX_WZ_withoutencoding: the project on the basis of the above, remove the codec section WIMAX_WZ_withoutprocessing: the project on the basis of the above, then remove the phase noise compensation, offset estimation WIMAX_WZ_withoutprocessing2: In the project on the basis of the above, use the new leader and pilot joint channel estimation scheme, the document " Standards-based 802_16d OFDM channel estimation and implementation of technology .kdh" because white noise channel simulation only reflects the QPSK modulation and RS-CC coding performance requires simulation SNR controllable SUI channel, to estimate the performance of channel equalization. When Doppler shift fd> 100Hz, joint channel estimation performance was stronger than the leading estimate, otherwise better estimation performance leader. For 600MHz center frequency transceiver requirements relative velocity Platform: |
Size: 40960 |
Author:陈茂 |
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Description: 1．采用Labview设计一虚拟函数信号发生器， 通过数据采集卡输出波形信号，调节信号的相关参数，可观察示波器上波形的变化情况。
⑴ 以NI MyDAQ数据采集卡作为输出接口；
⑵ 数据采集卡输出多种信号，至少完成三种波形：正弦波、三角波、方波(可调占空比)的输出，同时前面板上显示各输出波形；
⑶ 频率、幅值、初相位、直流偏移量和方波的占空比（0～100 ）等参数可以通过前面板控件调节。
⑷ 前面板可显示输出波形。-1. Labview design using a virtual function signal generator, data acquisition card output waveform signal, adjust the relevant parameters of the signal can be observed on an oscilloscope waveform changes.
⑴ with NI MyDAQ data acquisition card as output interface
⑵ data acquisition card output a variety of signals, to complete at least three waveforms: sine wave output, triangle wave, square wave (adjustable duty cycle), while each of the output waveform is displayed on the front panel
⑶ frequency, amplitude, initial phase, the DC offset and duty cycle square wave (0 to 100 ) and other parameters via the front panel controls to adjust.
⑷ output waveform can be displayed on the front panel. Platform: |
Size: 50176 |
Author:姚心恪 |
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Description: 假设截获了一段短波数字通信的信号，要求解调出最终的信息，每组解调出来后，将10组信息组合起来，恢复最终的信源输出数据。
先验信息：两组数据文件，编号为1、2，每组I、Q两路存放，格式为“int16”，采样率为9600Sa/s，其中第一组为单径情况，第二组为多径情况。
参数符合MIL-STD-188-110A标准；
同步序列为syn=seq.dat，BPSK调制；
接收机频率稳定度高于1e-6。
文件中有效信息总长度为333.75s，其中同步头长为5/12s，每时隙1/6s，训练序列占10 ，在数据之前；
交织方式为全交织，矩阵交织，列为1000，在比特级进行；
纠错码码率为1/2；
调制方式为BPSK、QPSK和8PSK中的一种，映射方式为二进制，BPSK相位偏移为0，其余两种为 。
-Suppose intercepted signal for a period of short-wave digital communications requires final demodulated information after each demodulated, combining 10 group information, to restore the final output data source.
Priori information: two sets of data file, numbered 1, 2, each I, Q two-way storage, the format is int16 , sampling rate 9600Sa/s, where the first group is a single path, the second group multipath situation.
Parameters meet MIL-STD-188-110A standard
Synchronization sequence syn = seq.dat, BPSK modulation
The frequency stability of the receiver is higher than 1e-6.
File payload total length of 333.75s, wherein the synchronization header length is 5/12s, each time slot 1/6s, accounting for 10 of the training sequence, before the data
Interleaving for the whole interleaving matrix interleaving, as 1000, carried out at the bit level
Error correction code rate of 1/2
The modulation scheme is BPSK, QPSK and 8PSK one, a binary mapping, the BPSK phase offset is 0, the Platform: |
Size: 4096 |
Author:suxiaogua |
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Description: 仿真相控阵雷达，观察方向图，旁瓣，仿真旁瓣出现的条件。仿真频率造成的偏移，仿真数字去斜。-Simulation of phased array radar, observe patterns, sidelobe side lobe simulation conditions arise. Offset, digital simulation simulation frequency due to oblique. Platform: |
Size: 10240 |
Author:yinchuan |
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Description: In distribution systems, the load has been a sudden
increase or decreases and it is like as nonlinear loads so the
load draw non-sinusoidal currents the AC mains and
causes the load harmonics and reactive power, and excessive
neutral currents that give pollution in power systems. Most
pollution problems created in power systems are due to the
nonlinear characteristics and fast switching of power
electronic devices. Shunt active filter based on current
controlled PWM converters are seen as a most viable solution.
This paper presents the harmonics and reactive power
compensation 3P4W micro-grid distribution system by
IP controlled shunt active. The technique which is used for
generate desired compensation current extraction based on
offset command instantaneous currents distorted or voltage
signals in the time domain because compensation time domain
response is quick, easy implementation and lower
computational load compared to the frequency domain.-In distribution systems, the load has been a sudden
increase or decreases and it is like as nonlinear loads so the
load draw non-sinusoidal currents the AC mains and
causes the load harmonics and reactive power, and excessive
neutral currents that give pollution in power systems. Most
pollution problems created in power systems are due to the
nonlinear characteristics and fast switching of power
electronic devices. Shunt active filter based on current
controlled PWM converters are seen as a most viable solution.
This paper presents the harmonics and reactive power
compensation 3P4W micro-grid distribution system by
IP controlled shunt active. The technique which is used for
generate desired compensation current extraction based on
offset command instantaneous currents distorted or voltage
signals in the time domain because compensation time domain
response is quick, easy implementation and lower
computational load compared to the frequency domain. Platform: |
Size: 14336 |
Author:hari |
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Description: 本文设计了一个简易函数发生器，可根据要求生成正弦波、方波、 三角波和锯齿波，波形的幅值、频率和电流偏置量均可在一定范围内调节。(A simple function generator is designed in this paper. Sine wave, Fang Bo wave, triangle wave and sawtooth wave can be generated according to the requirements. The amplitude, frequency and current offset of the waveform can be adjusted in a certain range.
The hardware circuit is designed with AT89C51 as the core, and uses digital to analog converter DAC0832, LCD AMPIRE128 * 64, integrated operational amplifier and other components.) Platform: |
Size: 35840 |
Author:胖鑫程序媛
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Description: DPA425是美国POWER Integrations公司生产的脉宽调制器，采用P、G、R三种不同的封装形式，各引脚功能如下：C脚为误差放大器和反馈电流的输入端，外部通过光电耦合器的下拉电流来调节占空比；L脚为电压检测端，为用户提供过压OV、过压UV、同步控制，在该脚引入同步脉冲，电路工作在外同步模式，但同步信号要高于振荡器频率；X脚为极限电流设置端，在该脚与源极之间接入不同参数的电阻，可设置DPA425的限流点；S脚为源极端，初级控制电路的公共点和参考点，内部连接功率。MOSFET的源极；D脚为漏极端。输入电压范围1～75VDC，在启动时可通过内部高压电流源为控制电路提供偏置电流。(DPA425 is American POWER Integrations company's pulse width modulator, P, G, R three different forms of packaging, each pin function is as follows: C foot as the input of error amplifier and feedback current, external through photoelectric coupler drop-down current to adjust the duty ratio; L feet for voltage detection, to provide users with overpressure OV, overvoltage UV, synchronous control, synchronous pulse, introduced in the foot, working circuit synchronous mode, but the synchronous signal than the oscillator frequency; The X foot is the limit current setting end, and the resistance of the different parameters is connected to the source and the limit of the DPA425 can be set. The s-foot is the source extreme, the primary control circuit common point and reference point, internal connection power. The source of MOSFET; D foot is the drain. The input voltage range is 1 ~ 75VDC, and the offset current can be provided by the internal high voltage current source at startup.) Platform: |
Size: 279552 |
Author:zbfg
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Search - frequency offset