Random Number Generators（隨機數生成）包括gaussian random number generator、uniform random number generator、low-frequency hold generator、1/f noise generator等5種隨機信號生成的c源代碼
The Audio File Library provides a uniform programming interface to
standard digital audio file formats.
This library allows the processing of audio data to and from audio
files of many common formats (currently AIFF, AIFF-C, WAVE, NeXT/Sun
.snd/.au, IRCAM, AVR, Amiga IFF/8SVX, and NIST SPHERE). The library
also supports compression (currently G.711 mu-law and A-law and IMA and
MS ADPCM) as well as PCM formats of all flavors (signed and unsigned
integer, single- and double-precision floating point).
unicap provides an uniform access to video capture devices. Currently you can access v4l, v4l2, IIDC 1394 ( DCAM ) cameras and video to firewire converters with a single API. New devices can be added via a plugin system
uniform random number generators
by Agner Fog, 2001 - 2007
randomc.zip contains a C++ class library of uniform random number generators of good quality.
The random number generators found in standard libraries are often of a poor quality, insufficient for large Monte Carlo calculations. This C++ implementation provides random number generators of a much better quality: Better randomness, higher resolution, and longer cycle lengths.
The same random number generators are available as libraries coded in assembly language for higher speed. These libraries can be linked into projects coded in other programming languages under Windows, Linux, BSD, etc. The library files are available in the archive asmlib.zip.
Non-uniform random number generators are provided in stocc.zip.
Generate 100 samples of a zero-mean white noise sequence with variance , by using a uniform random number generator.
a Compute the autocorrelation of for .
b Compute the periodogram estimate and plot it.
c Generate 10 different realizations of , and compute the corresponding sample autocorrelation sequences , and . Compute the average autocorrelation sequence as and the corresponding periodogram for .
d Compute and plot the average periodogram using the Bartlett method.
e Comment on the results in parts (a) through (d).
便攜式B型超聲診斷儀具有無創傷、簡便易行、相對價廉等優勢，在臨床中越來越得到廣泛的應用。它將超聲波技術、微電子技術、計算機技術、機械設計與制造及生物醫學工程等技術融合在一起。開展該課題的研究對提高臨床診斷能力和促進我國醫療事業的發展具有重要的意義。 便攜式B型超聲診斷儀由人機交互系統、探頭、成像系統、顯示系統構成。其基本工作過程是：首先人機交互系統接收到用戶通過鍵盤或鼠標發出的命令，然后成像系統根據命令控制探頭發射超聲波，并對回波信號處理、合成圖像，最后通過顯示系統完成圖像的顯示。 成像系統作為便攜式B型超聲診斷儀的核心對圖像質量有決定性影響，但以前研制的便攜式B型超聲診斷儀的成像系統在三個方面存在不足：第一、采用的是單片機控制步進電機，控制精度不高，導致成像系統采樣不精確；第二、采用的數字掃描變換算法太粗糙，影響超聲圖像的分辨率；第三、它的CPU多采用的是51系列單片機，測量速度太慢，同時也不便于系統升級和擴展。 針對以上不足，提出了基于FPGA的B型超聲成像系統解決方案，采用Altera公司的EP2C5Q208C8芯片實現了步進電機步距角的細分，使電機旋轉更勻速，提高了采樣精度；提出并采用DSTI-ULA算法（uniform Ladder Algorithm based on Double Sample and Trilinear Interotation）在FPGA內實現數字掃描變換，提高了圖像分辨率；人機交互系統采用S3C2410-AL作為CPU，改善了測量速度和系統的擴展性。 通過對系統硬件電路的設計、制作，軟件的編寫、調試，結果表明，本文所設計的便攜式B型超聲成像系統圖像分辨率高、測量速度快、體積小、操作方便。本文所設計的便攜式B型超聲診斷儀可在野外作業和搶險（諸如地震、抗洪）中發揮作用，同時也可在鄉村診所中完成對相關疾病的診斷工作。
Calculation of the Differential Impedance of Tracks on FR4 substrates
There is a discrepancy between calculated and measured values of impedance for differential transmission lineson FR4. This is especially noticeable in the case of surface microstrip configurations. The anomaly is shown tobe due to the nature of the substrate material. This needs to be considered as a layered structure of epoxy resinand glass fibre. Calculations, using Boundary Element field methods, show that the distribution of the electricfield within this layered structure determines the apparent dielectric constant and therefore affects theimpedance. Thus FR4 cannot be considered to be uniform dielectric when calculating differential impedance.
