A digital fi‘equeney meter designed with FPGA development software Q-~us 11 is introduced．The 1 Hz—l MHz input measured pulse signals of the digital ii‘equency meter can be used for measuring frequency，period，pulse width and duty ratio，etc．The test results stably display O71 3 seven—segment numeric tubes，and the measuring ranges may be switched over automatically．The measuring error is equal to or less than 0．1％．
标签： development introduced designed software
上传时间： 2016-04-09
上传用户：stewart·
DFT(Discrete Fourier Transformation)是数字信号分析与处理如图形、语音及图像等领域的重要变换工具，直接计算DFT的计算量与变换区间长度N的平方成正比。当N较大时，因计算量太大，直接用DFT算法进行谱分析和信号的实时处理是不切实际的。快速傅立叶变换(Fast Fourier Transformation，简称FFT)使DFT运算效率提高1～2个数量级。其原因是当N较大时，对DFT进行了基4和基2分解运算。FFT算法除了必需的数据存储器ram和旋转因子rom外，仍需较复杂的运算和控制电路单元，即使现在,实现长点数的FFT仍然是很困难。本文提出的FFT实现算法是基于FPGA之上的，算法完成对一个序列的FFT计算，完全由脉冲触发，外部只输入一脉冲头和输入数据，便可以得到该脉冲头作为起始标志的N点FFT输出结果。由于使用了双ram，该算法是流型(Pipelined)的，可以连续计算N点复数输入FFT，即输入可以是分段N点连续复数数据流。采用DIF(Decimation In Frequency)-FFT和DIT(Decimation In Time)-FFT对于算法本身来说是无关紧要的，因为两种情况下只是存储器的读写地址有所变动而已，不影响算法的结构和流程，也不会对算法复杂度有何影响。
标签： Transformation Discrete Fourier DFT
上传时间： 2016-04-12
上传用户：lx9076
在DAB系统中的频率同步，载频同步，参考一下Carrier frequency offset estimation of DAB receiver based on phase reference symbol
上传时间： 2014-11-23
上传用户：songrui
// // Histogram Sample // This sample shows how to use the Sample Grabber filter for video image processing. // Conceptual background: // A histogram is just a frequency count of every pixel value in the image. // There are various well-known mathematical operations that you can perform on an image // using histograms, to enhance the image, etc. // Histogram stretch (aka automatic gain control): // Stretches the image histogram to fill the entire range of values. This is a "point operation," // meaning each pixel is scaled to a new value, without examining the neighboring pixels. The // histogram stretch does not actually require you to calculate the full histogram. The scaling factor // is calculated from the minimum and maximum values in the image.
标签： Sample Histogram Grabber sample
上传时间： 2013-12-15
上传用户：ryb
Squaring circuits are an important building block for impulse-radio UWB non-coherent receivers. This work proposes a squarer, based on the quadratic law of saturated transistors. Such a circuit has already been proposed for lower frequency applications, therefore this work focuses on the extension to ultra wide bandwidth, with particular care to the consequences related to the deviation from the ideal quadratic law of 0.18μm CMOS transistors.
标签： impulse-radio non-coherent important receivers
上传时间： 2013-12-24
上传用户：kikye
This paper presents the key circuits of a 1MHz bandwidth, 750kb/s GMSK transmitter. The fractional-N synthesizer forming the basis of the transmitter uses a combined phasefrequency detector (PFD) and digital-to-analog converter (DAC) circuit element to obtain >28dB high frequency noise reduction when compared to classicalfrequency synthesis.
标签： fractional-N transmitter bandwidth circuits
上传时间： 2016-04-14
上传用户：er1219
The second volume in the Write Great Code series supplies the critical information that today s computer science students don t often get from college and university courses: How to carefully choose their high-level language statements to produce efficient code. Write Great Code, Volume 2: Thinking Low-Level, Writing High-Level, teaches software engineers how compilers translate high-level language statements and data structures into machine code. Armed with this knowledge, a software engineer can make an informed choice concerning the use of those high-level structures to help the compiler produce far better machine code--all without having to give up the productivity and portability benefits of using a high-level language
标签： information the critical supplies
上传时间： 2014-02-21
上传用户：luke5347
/* * The internal form of a hash table. * * The table is an array indexed by the hash of the key collisions * are resolved by hanging a linked list of hash entries off each * element of the array. Although this is a really simple design it * isn t too bad given that pools have a low allocation overhead. */ split from apache for general usage
上传时间： 2014-01-07
上传用户：gtf1207
This LDPC software is intended as an introduction to LDPC codes computer based simulation. The pseudo-random irregular low density parity check matrix is based on Radford M. Neal’s programs collection, which can be found in [1]. While Neal’s collection is well documented, in my opinion, C source codes are still overwhelming, especially if you are not knowledgeable in C language. My software is written for MATLAB, which is more readable than C. You may also want to refer to another MATLAB based LDPC source codes in [2], which has different flavor of code-writing style (in fact Arun has error in his log-likelihood decoder).
标签： LDPC introduction simulation software
上传时间： 2014-01-14
上传用户：大融融rr
Using LabVIEW 8.5 Language to control Tektronix AWG3102. This program can select output waveform, frequency and amplitude.
标签： Tektronix Language waveform LabVIEW
上传时间： 2016-05-17
上传用户：xlcky
