便攜式信號采集在機器健康診斷系統中有較高的應用價值。機器健康診斷的信號特點是包括低頻信號。本文研究是為了實現簡易而且低成本的低頻便攜式信號采集。以Microchip公司單片機PIC18F1320為核心設計信號采集電路，實現了信號的采集和保存。系統采用串行電可擦除芯片24LC32A保存數據，經過有線通信，信號數據由串行口通過MAX232芯片輸送到微型計算機接收和保存，最后繪制出信號波形。 微型計算機程序采用Visual Basic編程。研究成功采樣頻率為3 kHz的復雜信號，證明該方案符合設計要求。 Abstract: Portable signal acquisition is useful in machine health monitoring systems. The signal characteristics of machine health monitoring includes low frequency signals. The goal of this study is to realize simple, inexpensive and portable low frequency signal sampling. This paper provides the project of signal acquisition system design based on PIC18F1320 microcontroller manufactured by the Microchip Technology Incorporation to achieve signal sampling and storage. The system adopted EEPROM 24LC32A to store the signal data. The microcomputer received data via wired link with the MAX232 IC through the serial port. The microcomputer program, programmed in Visual Basic, received the data, stored it and plotted the signal. The study successfully samples 3kHz complicated signals and thus meets the design requirement.
上傳時間： 2013-11-19
上傳用戶：moerwang
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
上傳時間： 2013-10-23
上傳用戶：copu
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.
上傳時間： 2014-04-02
上傳用戶：han_zh
在偉福集成環境下使用PICC.講述在偉福集成環境如可設置PICC, 簡單的調試步驟. 更詳細的說明請參閱偉福仿真器使用手冊.關于如何在MPLAB 下使用PICC C 語言, 請參閱Microchip 相應的手冊. 2-1 安裝PICC將CD-ROM 裝入光驅, 自動運行程序將自動啟動, 如果你已禁止自動運行功能, 可以直接運行: cd_drive:\compiler\install.exe安裝程序將指導你完成PICC 的安裝.2-2 設置偉福集成環境在偉福集成環境中, 將編譯器路徑指向PICC 所在目錄將Ｃ命令行設置為: -16F877 –G –O –Zg -c將連接命令行設置為: -16F877 –G –O -Zg其中: -16F877 為芯片型號–G –O -c 為源程序調試設置項, 不可修改–Zg 為打開優化你可以在命令行中加入其它控制項2-3 調試Ｃ語言在WAVE\samples 目錄下有一個PIC C 語言的例子程序: PIC_C.PRJ.１. 打開PIC_C 項目.２. 編譯該項目(F9)３. 用F7,F8 單步調試例子程序４. 打開觀察窗口觀察變量
上傳時間： 2013-10-16
上傳用戶：lili123
jbuzzer is an application written in Java that allows mapping your comuter keyboard to sounds. It supports short samples as well as streaming format. The GUI allows dynamically adding and removing new slots for samples.
標簽： application keyboard jbuzzer comuter
上傳時間： 2014-12-07
上傳用戶：qoovoop
minigui 開發軟件附帶實例源碼，mg-samples-1.6.2.tar.gz。
上傳時間： 2015-03-27
上傳用戶：youmo81
This a Bayesian ICA algorithm for the linear instantaneous mixing model with additive Gaussian noise [1]. The inference problem is solved by ML-II, i.e. the sources are found by integration over the source posterior and the noise covariance and mixing matrix are found by maximization of the marginal likelihood [1]. The sufficient statistics are estimated by either variational mean field theory with the linear response correction or by adaptive TAP mean field theory [2,3]. The mean field equations are solved by a belief propagation method [4] or sequential iteration. The computational complexity is N M^3, where N is the number of time samples and M the number of sources.
標簽： instantaneous algorithm Bayesian Gaussian
上傳時間： 2013-12-19
上傳用戶：jjj0202
linux 的引導程序源碼The Microsoft® Windows® Software Development Kit (SDK) provides the documentation, samples, header files, libraries, and tools you need to develop applications that run on Windows. The applications you develop with this edition of the SDK can run on the x86, x64 and Itanium-based versions of Windows Server 2003 SP1, Windows XP SP2, Windows XP x64 Pro Edition, and Windows 2000. A new custom install allows you to select components you wish to install on a more granular level.
標簽： documentation Development Microsoft reg
上傳時間： 2013-12-20
上傳用戶：我們的船長
用LPC213X系列的PWM來產生語音。語音數據來源于PC機轉換后得到的。最大可以是16位的。 由于是PWM所以輸出端口需要低通濾波才能夠得到比較干凈的聲音。 可以經過修改使用LPC2132以上的ARM的D/A來產生。 This project outputs audio on PWM0 using wave samples that are stored in the on-chip Flash ROM.
上傳時間： 2014-11-07
上傳用戶：zhanditian
sharepoint portal server的sdk英文版 The SharePoint Products and Technologies 2003 Software Development Kit (SDK) contains conceptual overviews, programming tasks, samples, and references to guide you in developing solutions based on SharePoint products and technologies.
標簽： Technologies Development sharepoint SharePoint
上傳時間： 2015-06-15
上傳用戶：zhyiroy
