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
為了使音頻信號分析儀小巧可靠，成本低廉，設計了以2片MSP430F1611單片機為核心的系統。該系統將音頻信號送入八階巴特沃茲低通濾波器，對信號進行限幅放大、衰減、電平位移、緩沖，并利用一單片機負責對前級處理后的模擬信號進行采樣，將采集得到的音頻信號進行4 096點基2的FFT計算，并對信號加窗函數提高分辨率，另一單片機負責對信號的分析及控制顯示設備。此設計精確的測量了音頻信號的功率譜、周期性、失真度指標，達到較高的頻率分辨率，并能將測量結果通過紅外遙控器顯示在液晶屏上。 Abstract: o make the audio signal analyzer cheaper， smaller and more reliable， this system sends the audio signal to the eight-order butterworth filter， and then amplifies， attenuates， buffers it in a limiting range， transfers the voltage level of the signal before utilizing two MSP430F1611 MCU to realize the audio analysis. One is charged for sampling and dealing with the processed audio signal collected by the 4096 point radix-2 FFT calculation and imposes the window function to improve the frequency resolution. The other one controls the display and realizes the spectrum， periodicity， power distortion analysis in high resolution which is displayed in the LCD screen through the infrared remote control.
上傳時間： 2013-12-11
上傳用戶：jasonheung
介紹了一種基于C8051F020單片機的多路壓力測量儀。該測量儀選用電阻應變式壓力傳感器采集壓力信號，并經放大電路處理后送入C8051F020單片機，再由C8051F020單片機內部的A/D轉換器將采集到的壓力信號進行模數轉化，然后分別對數據進行存儲和顯示。該測量儀能測量6路壓力信號，并且各測量點都能單獨檢測和設置。由于采用了C8051F020單片機，簡化了硬件電路，增強了抗干擾能力，使得測量儀具有測量精度高，沖擊小等特點。 Abstract: A measurement apparatus for multi-channel pressure based on single chip microcomputer is introduced.It can measure 6 channels signal of the pressure，and the pressure measure points can be detection and located individually.The pressure signal sampling is obtained by resistor stress-type pressure sensors，the digital signals of 6 channels are collected through amplifying and adjustment circuit of pressure signals and internal integrated A/D converter of MCU.Finally，and it realizes the function to store and display data separately.C8051F020 was used to made hardware circuit simple，and it also enhanced the anti-interference ability.It features high precision and little impact.
上傳時間： 2013-11-16
上傳用戶：yare
Luminary Micro Stellaris™ microcontrollers that are equipped with an analog-to-digital converter(ADC), use an innovative sequence-based sampling architecture designed to be extremely flexible,yet easy to use. This application note describes the sampling architecture of the ADC. Sinceprogrammers can configure Stellaris microcontrollers either through the powerful StellarisFamilyDriver Library or through direct writes to the device's control registers, this application note describesboth methods. The information presented in this document is intended to complement the ADCchapter of the device datasheet, and assumes the reader has a basic understanding of howADCsfunction.
標簽： Microcontr Stellaris Using the
上傳時間： 2013-10-14
上傳用戶：blans
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
傳統的人工耳蝸語音處理器采用ASIC設計，投入成本高，可移植性差，設計了一種基于TMS320VC5509A的人工耳蝸語音處理器。該處理器采用雙麥克風接受語音信號，實現了語音信號的自適應噪聲消除和CIS （Continuous Interleaved Sampling） 方案。同一段語音由DSP采樣處理得到的刺激脈沖與MATLAB采樣處理的結果基本相同。實驗結果表明，基于DSP的人工耳蝸語音處理器能實現語音信號中噪聲的消除并得到良好的刺激脈沖。
上傳時間： 2013-10-22
上傳用戶：23333
在綜合分析諧波勵磁無刷同步發電機勵磁控制系統的基礎上,對其勵磁控制策略進行了研究,開發了一套基于DSP( TMS320F2812) 控制的新型柴油發電機勵磁控制系統,該系統采用參數自適應模糊PID 控制勵磁,選用交流采樣方式實時檢測各信號的瞬時特性,系統仿真結果以及在1 臺25 kW 工頻柴油發電機上的試驗結果證明了該控制器具有較好的電壓調節特性,系統穩態和暫態性能完全滿足發電機對勵磁系統的要求。關鍵詞:勵磁調節;模糊PID 控制;數字信號處理器;交流采樣 Abstract :According to the general analysis of the excitation cont rol system of the harmonious wave excitation brushless synchronous generator and it s characteristics ,a new type of diesel generator excitation cont rol system based on DSP( TMS320F2812) was designed. An adaptive fuzzy PID cont rol of excitation is used in this system. To detect the t ransient characteristics of the signals in a timely manner ,AC sampling was applied.The system simulation result s and the testing result s f rom a 25 kW diesel generator (50 Hz) can prove that the voltage regulation characteristics of the excitation cont rol system are very well ,and both the steadyOstate performance and the t ransient performance of the generator are also good.Key words :excitation cont rol ;fuzzy PID cont rol ;digital signal processor (DSP) ;AC sampling
上傳時間： 2013-10-29
上傳用戶：fxf126@126.com
為提升虛擬儀器傳輸速率與實時性能，擴展監測范圍，在VC的軟件平臺上設計了一種全功能虛擬示波器。與傳統虛擬示波器相比，該系統采用嵌入式系統完成信號采集，采用工業以太網為傳輸介質，通過線性插值算法和多線程編程思想，實現波形顯示、參數計算、頻譜分析以及波形存儲及回放功能。實驗結果表明，該虛擬示波器可以實現20 kHz采樣頻率下的波形精確顯示，達到預期的各項指標。 Abstract: o enhance the transfer rate and real-time of virtual instrument performance， expand scope of monitoring， this paper uses the VCs software platform to design a fully functional virtual oscilloscope. Compared with traditional virtual oscilloscope， this system adopts the embedded system to complete the data acquisition， industrial Ethernet as the transmission medium used by the linear interpolation algorithm and multi-threaded programming ideas， namely to achieve waveform display， parameter calculation， spectrum analysis and waveform storage and playback. Experimental results show that the virtual oscilloscope can accurately display the waveform with 20kHz sampling frequency， and achieve the desired targets.
上傳時間： 2013-11-25
上傳用戶：wbwyl
Abstract: High-speed and low-speed data converters serve critical functions in modern broadband mobile radios. This application note outlines how todetermine high-speed data converter performance requirements in baseband sampling radio architectures. Also, system partition strategies andadvantages are outlined when considering a high-speed analog front-end (AFE) solution.
上傳時間： 2013-11-02
上傳用戶：jjj0202
Abstract: This application note discusses the REF pin functionality in the indirect current-feedbackarchitecture for instrumentation amplifiers. This article compares the importance of a REF buffer in a
上傳時間： 2015-01-03
上傳用戶：時代將軍
