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Description: 1 学习在CVI环境里面使用非NI数据采集卡。
2 学习用过零法计算被测每个周期采样点数。
3 学习数据采集卡采样间隔的测定。
4 学习计算被测信号的频率和周期。
5 熟悉FFT算法原理。
-One study in the CVI environment inside the use of non-NI data acquisition card. 2 study used method to calculate the measured zero sampling points per cycle. 3 study data acquisition card sampling interval measurement. 4 study calculated the measured signal frequency and cycle. 5 familiar with the FFT algorithm.
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Author: 楚燕 |
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Description: 用FFT对信号，数据点512，进行滤波将频率为8—15Hz的波滤去。采样间隔0.02。-Using FFT of signal, data points 512, for filtering the frequency of 8-15Hz wave least squares. Sampling interval 0.02.
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Author: conan |
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Description: 格式 [sqnr,a_quan,code]=u_pcm(a,n)
输入样值序列a 、量化电平数目n, 程序计算量化间隔、进行均匀量化、进行编码、计算量化信噪比， 返回量化信噪比squn、编码前的量化序列a_quan、编码后的码序列code。
-Format [sqnr, a_quan, code] = u_pcm (a, n) input sample value sequence a, the number of quantization levels n, the calculation procedures to quantify interval, the uniform quantization, coding, computing quantization noise ratio, return quantization noise ratio squn, to quantify the pre-coding sequence a_quan, coding sequences after the code.
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Author: wx |
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Description: ex6_1 ～ ex6_3二项分布的随机数据的产生
ex6_4 ～ ex6_6通用函数计算概率密度函数值
ex6_7 ～ ex6_20常见分布的密度函数
ex6_21 ～ ex6_33随机变量的数字特征
ex6_34 采用periodogram函数来计算功率谱
ex6_35 利用FFT直接法计算上面噪声信号的功率谱
ex6_36 利用间接法重新计算上例中噪声信号的功率谱
ex6_37 采用tfe函数来进行系统的辨识，并与理想结果进行比较
ex6_38 在置信度为0.95的区间上估计有色噪声x的PSD
ex6_39 在置信度为0.95的区间上估计两个有色噪声x，y之间的CSD
ex6_40 用程序代码来实现Welch方法的功率谱估计
ex6_41 用Welch方法进行PSD估计，并比较当采用不同窗函数时的结果
ex6_42 用Yule-Walker AR法进行PSD估计
ex6_43 用Burg算法计算AR模型的参数
ex6_44 用Burg法PSD估计
ex6_45 比较协方差方法与改进的协方差方法在功率谱估计中的效果
ex6_46 用Multitaper法进行PSD估计
ex6_47 用MUSIC法进行PSD估计
ex6_48 用特征向量法进行PSD估计-ex6_1 ~ ex6_3 binomial distribution of the generated random data
ex6_4 ~ ex6_6 generic function value of the probability density function
ex6_7 ~ ex6_20 common distribution density function
ex6_21 ~ ex6_33 figure characteristics of random variables
periodogram function ex6_34 used to calculate the power spectrum
ex6_35 direct method using FFT signal above the noise of the power spectrum
ex6_36 recalculated using the indirect method on the example of the power spectrum of noise signal
tfe function ex6_37 used for system identification, and results were compared with the ideal
ex6_38 at 0.95 confidence interval for the estimated colored noise x on the PSD
ex6_39 at 0.95 confidence interval of the two colored noise on the estimated x, y between the CSD
ex6_40 code used to achieve the Welch method of power spectrum estimation
Welch method ex6_41 with PSD estimates, and compare different window function when the results when
ex6_42 using Yule-Walker AR method is esti
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Author: 张满超 |
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Description: 用MATLAB中的FFt算法及AR模型来研究RR间期-The FFt with MATLAB algorithms and AR model to study the RR interval
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Size: 54272 |
Author: hukai |
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Description: FFT的奈奎斯特频率为 ，（ 为采样间隔）实际上的FFT变换点数要求为2的n次幂，各点所对应的频率是从 到 ，求出 后，可以用 ，这里N为FFT变换的点数。如变换点数为2048，由于对称性，实际有用的点数为1024个。
在该程序中，做完富氏变换后，已经将数据按照频率从0到 到0的顺序排好。
在运行结果中，只需存储左下角的1/4区域的数据即可。
-FFT of the Nyquist frequency, (for the sampling interval) is actually the FFT, the n number of points required for the power of 2, the frequency corresponding to each point is to, find, you can use the FFT, where N points. Such as the transformation point to 2048, due to the symmetry, the actual useful points to 1024. In the process, done after the Fourier transform has the data in accordance with the frequency range from 0 to 0 in order to line up. In the run results, only the lower left corner of the store 1/4 of regional data can be.
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Description: 2dFFT的奈奎斯特频率为 ，（ 为采样间隔）实际上的FFT变换点数要求为2的n次幂，各点所对应的频率是从 到 ，求出 后，可以用 ，这里N为FFT变换的点数。如变换点数为2048，由于对称性，实际有用的点数为1024个。
在该程序中，做完富氏变换后，已经将数据按照频率从0到 到0的顺序排好。
在运行结果中，只需存储左下角的1/4区域的数据即可。
-2dFFT of the Nyquist frequency, (for the sampling interval) is actually the FFT, the n number of points required for the power of 2, the frequency corresponding to each point is to, find, you can use the FFT, where N points. Such as the transformation point to 2048, due to the symmetry, the actual useful points to 1024. In the process, done after the Fourier transform has the data in accordance with the frequency range from 0 to 0 in order to line up. In the run results, only the lower left corner of the store 1/4 of regional data can be.
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Description: 做FFT只能看出信号在0到分析频率（采样频率的一半）之间的相对分布，或者说得到以采样频率归一化的频率。
采样频率即取样频率，指每秒钟取得信号样本的次数。所以，采样频率就是1/（delta t），其中delta t为连续采两次信号的时间间隔。
采样频率/采样点数=频率分辨率。
-Signal do FFT can only be seen in the 0 to the analysis frequency (half the sampling frequency) relative distribution, or get to the sampling frequency normalized frequency. Sampling frequency is the sampling frequency, refers to the number of times per second to obtain the signal samples. Therefore, the sampling frequency is 1/(delta t), which collected two consecutive delta t is the time interval signal. Sampling frequency/frequency resolution = sampling points.
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Size: 4096 |
Author: 代林鹏 |
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Description: OFDM的原理在matalb中实现源代码，包括FFT和IFFT,加入保护间隔，循环前缀和子载波等。-Principle of OFDM is implemented in matalb source code, including FFT and IFFT, adding guard interval, cyclic prefix and sub-carrier, etc.
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Author: johnnyluo |
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Description: Matlab程序，GUI窗口
用FFT程序计算有限长度正弦信号y=sin(2*pi*f*t) ,0<=t<=N*T-FFT program calculate the finite length of the sinusoidal signal y = sin (2* pi* f* t), 0 < = t < = N* T respectively the DFT results obtained and analyzed and discussed in the following cases: a) the signal frequency f = 50Hz, the sampling the credited with N = 32, the sampling interval T = 0.000625sb) signal frequency f = 50Hz, the sampling points of N = 32, the sampling interval T = 0.005sc), the signal frequency f = 50 Hz, the sampling points N = 32, the sampling interval T = 0.0046875sd) signal frequency f = 50Hz, the sampling points of N = 32, the sampled interval T = 0.004se) signal frequency f = 50Hz, the sampling points of N = 64, the sampling interval the T = 0.000625sf) signal frequency f = 250Hz, the sampling points N = 32, the sampling interval T = 0.005sg) c) a signal-post 32, to do a 64-point FFT
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Author: moumiao |
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Description: 1-Log magnitude using 1024 point FFT over 25ms
2- Hamming Window at duration 1024 over 25ms
3- Log magnitude using 1024 FFT over interval 10ms
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Size: 741376 |
Author: mohanad |
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Description: 通信系统与仿真作业：
1）设计π/4-DPSK或16-QAM调制器仿真程序， 画出时域波形、 正交分量、同相分量波形，眼图，散点图等。
2）利用MATLAB进行DPSK在高斯信道下的BER性能仿真，并将结果与PSK性能进行比较。
3）已知 OFDM的数据传输速率为19.2Kbps， OFDM 符号长度为320，保护间隔为32点，子载波数为128，IFFT/FFT点数为256，载波频率320KHz，调制方案采用QPSK，仿真其在高斯信道下的BER性能。
-Communication systems and simulation tasks: 1) Design π/4-DPSK or 16-QAM modulator simulation program, draw time-domain waveform, quadrature component, in-phase component waveforms, eye diagrams, scatter plots, etc. 2) the use of MATLAB for DPSK in AWGN channel BER performance simulation, and the results are compared with PSK performance. 3) the known OFDM data transmission rate of 19.2Kbps, OFDM symbol length is 320, the guard interval is 32 points, the number of sub-carriers 128, IFFT/FFT points is 256, the carrier frequency is 320KHz, using the modulation scheme QPSK, simulation of the in Gaussian channel BER performance.
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Author: wander |
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Description: 时间同步后即可确定每帧数据的起始位置，这样就能完整的截取下每一帧。但是，数据中还带有频偏信息。在常规的通信系统中，多普勒很小仅仅会带来很小的频偏，但是在大多普勒的情况下，频偏将非常大，20马赫的速度将会带来将近34K的频偏。因此，如何很好的纠正频偏即为本系统的难点。
OFDM中，我们将大于子载波间隔倍数的频偏称为整数倍频偏，而将小于一个子载波间隔的频偏称为小数倍频偏。频偏矫正精度只要能保证小于十分之一倍的子载波间隔，频偏就不会对均衡和解调造成影响。本文中我们借鉴这种思想，由于硬件资源限制，我们将在接收端做64点FFT，即相当于将频域划分为64份，我们将小于 的频偏称为小数倍频偏，将 整数倍的频偏称为整数倍频偏。本程序即基于SCHIMDL经典方法完成小数倍频偏纠正-After time synchronization can determine the starting position of each frame data, so you can complete the interception of each frame. However, in the data with frequency information. In conventional communication systems, doppler small will bring only small deviation, but in the case of most of the doppler, frequency PianJiang is very large, 20 Mach speed will lead to deviation of nearly 34 k. Therefore, how to good to correct deviation is the difficulty of this system.
OFDM, we will be bigger than the sub-carrier spacing ratio of frequency deviation is called the integer frequency offset, and the interval will be less than a child carrier frequency offset is called decimal frequency doubling. Deviation is less than one over ten times as long as can guarantee accuracy of sub-carrier spacing, deviation will not affect balance and demodulation. This article, we draw lessons from the idea, due to the limited hardware resources, we will do 64 points FFT at the receiving end, which is equ
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Author: Nico_S |
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Description: 频谱混叠的情况及原因，：当周期T一定时，抽样频率越大，其采样的时间间隔越短，图像越逼真-Aliasing circumstances and reasons: when the period T is constant, the larger the sampling frequency, the sampling interval shorter, more lifelike images
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Size: 508928 |
Author: 李祥 |
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Description: ex6_1 ～ ex6_3二项分布的随机数据的产生
ex6_4 ～ ex6_6通用函数计算概率密度函数值
ex6_7 ～ ex6_20常见分布的密度函数
ex6_21 ～ ex6_33随机变量的数字特征
ex6_34 采用periodogram函数来计算功率谱
ex6_35 利用FFT直接法计算上面噪声信号的功率谱
ex6_36 利用间接法重新计算上例中噪声信号的功率谱
ex6_37 采用tfe函数来进行系统的辨识，并与理想结果进行比较
ex6_38 在置信度为0.95的区间上估计有色噪声x的PSD
ex6_39 在置信度为0.95的区间上估计两个有色噪声x，y之间的CSD
ex6_40 用程序代码来实现Welch方法的功率谱估计
ex6_41 用Welch方法进行PSD估计，并比较当采用不同窗函数时的结果
ex6_42 用Yule-Walker AR法进行PSD估计
ex6_43 用Burg算法计算AR模型的参数
ex6_44 用Burg法PSD估计
ex6_45 比较协方差方法与改进的协方差方法在功率谱估计中的效果
ex6_46 用Multitaper法进行PSD估计
ex6_47 用MUSIC法进行PSD估计
ex6_48 用特征向量法进行PSD估计
-ex6_1 ~ ex6_3 binomial random data
ex6_4 ~ ex6_6 generic function to calculate the probability density function value
ex6_7 ~ common distribution density function ex6_20
ex6_21 ~ ex6_33 numerical characteristics of random variables
ex6_34 using periodogram function to calculate the power spectrum
ex6_35 direct method using FFT power spectrum of the signal above the noise
ex6_36 use the indirect method to recalculate the case of the power spectrum of the noise signal
ex6_37 tfe functions to use the identification system and the results are compared with the ideal
ex6_38 the confidence level of the estimated colored noise x 0.95 range on PSD
ex6_39 the confidence level of the estimated two colored noise on the 0.95 x interval between the CSD y
ex6_40 application code to implement the Welch method of power spectrum estimation
The results ex6_41 with Welch PSD estimation method and compared using different window function when the time
ex6_42 with Yule-Walker AR method PSD esti
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Author: Bruce |
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Description: 提出了一种细化FFT的短时傅立叶变换(shorttimeFouriertransform,简称STFT)时频分析新方法.STFT实 质为加窗的傅立叶变换,在窗内数据满足平稳性条件下利用傅立叶变换获得频谱,并依据时间间隔移动窗函数最终得到时频表示.细化FFT在分析频率范围内具有较高的频率分辨率,将细化FFT应用于STFT的窗内数据,可有效提高STFT的时频聚集性-Proposed a frequency analysis of short-time Fourier transform FFT refinement (shorttimeFouriertransform, referred to as STFT) A new method. STFT essence of the windowed Fourier transform, the data within the window satisfies the stationary conditions spectrum obtained by Fourier transform, and based time interval finally get moving window function frequency representation. refinement FFT has a higher frequency resolution in the analysis of the frequency range, the refinement of the FFT applied STFT window data, which can effectively improve the STFT time-frequency aggregation
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Size: 2048 |
Author: zhujun |
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Description: Plot the log-magnitude of the Fourier transform of the signal over the interval [0, π], using
a 1024-point FFT. The signal should be windowed with a Hamming window of two different
durations: 25 ms and 10 ms with the window placed at the signal’s center in each case. Show
the log-magnitude plot for each duration.
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Size: 1024 |
Author: asdamha |
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Description: 简单的OFDM仿真，采用QPSK调制，有串并转换，保护间隔，fft/ifft等-Simple OFDM simulation using QPSK modulation, there are serial to parallel conversion, guard interval, fft/ifft etc.
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Size: 1024 |
Author: sunny liu |
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Description: java平台下的FFT变换，实现通过RR间期计算HRV频域分析-FFT transform java platform, to achieve a frequency domain HRV calculated by the RR interval analysis
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Author: 翟俊达 |
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Description: 利用傅氏级数展开法，对合成信号进行傅立叶分解,有限区间信号的傅氏级数展开定理(The Fourier series expansion method is used to decompose the synthetic signal by Fu Liye, and the Fourier series expansion theorem of the finite interval signal)
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Author: 璐娜
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