·詳細說明：MP3編碼庫，可直接將wav,aiff格式的音頻文件壓縮成碼流量為128Kbps的mp3文件-Mp3encode is a kind of mp3 encoded library which can compress wav,aiff files to mp3 files of 128kbps data flow.文件列表: mp3encoder-05-07-04 &nbs
上傳時間： 2013-06-14
上傳用戶：baitouyu
Methods for designing a maintenance simulation training system for certain kind of radio are introduced. Fault modeling method is used to establish the fault database. The system sets up some typical failures， follow the prompts trainers can locate the fault source and confirm the type to accomplish corresponding fault maintenance training. A training evaluation means is given to examining and evaluating the training performance. The system intuitively and vividly shows the fault maintenance process， it can not only be used in teaching， but also in daily maintenance training to efficiently improve the maintenance operation level. Graphical programming language LabVIEW is used to develop the system platform.
上傳時間： 2013-11-19
上傳用戶：3294322651
Abstract: This tutorial discusses proper printed-circuit board (PCB) grounding for mixed-signal designs. Formost applications a simple method without cuts in the ground plane allows for successful PCB layouts withthis kind of IC. We begin this document with the basics: where the current flows. Later, we describe how toplace components and route signal traces to minimize problems with crosstalk. Finally, we move on toconsider power supply-currents and end by discussing how to extend what we have learned to circuits withmultiple mixed-signal ICs.
上傳時間： 2013-11-04
上傳用戶：pol123
鎖定放大是微弱信號檢測的重要手段?；谙嚓P檢測理論，利用開關電容的開關實現鎖定放大器中乘法器的功能，提出開關電容和積分器相結合以實現相關檢測的方法，并設計出一種鎖定放大器。該鎖定放大器將微弱信號轉化為與之相關的方波，通過后續電路得到正比于被測信號的直流電平，為后續采集處理提供方便。測量數據表明鎖定放大器前級可將10-6 A的電流轉換為10-1 V的電壓，后級通過帶通濾波器級聯可將信號放大1×105倍。該方法在降低噪聲的同時，可對微弱信號進行放大，線性度較高、穩定性較好。 Abstract: Lock-in Amplifying（LIA）is one of important means for weak signal detection. Based on cross-correlation detection theory， switch in the swithched capacitor was used as multiplier of LIA， and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave， then DC proportional to measured signal was obtained through follow-up conditioning circuit， providing convenience for signal acquisition and processing. The measured data shows that the electric current（10-6 A） can be changed into voltage（10-1 V） by LIA， and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the weak signal is amplified. It has the advantages of good linearity and stability.
上傳時間： 2013-11-29
上傳用戶：黑漆漆
為提高太陽能的利用率，以ATmega8單片機為控制核心，設計了一套光電跟蹤與視日運動軌跡跟蹤互補控制的雙軸太陽跟蹤器。該跟蹤器在晴天時，利用光敏電阻采集光強判斷太陽位置,控制步進電機實現光電跟蹤；在陰天時，采集時鐘器件PCF8583的時間信息,計算當前太陽位置來實現視日運動軌跡跟蹤。實驗表明：該太陽跟蹤器能在不同天氣狀況下對太陽進行較準確地跟蹤，能量接收效率提高了30%，達到充分利用太陽能的目的。 Abstract: To improve the utilization rate of solar energy，a kind of solar tracking controller which effectively combined the sun angle tracking and photo electric tracking based on ATmega8is designed.In the sunny days，the solar tracking con-troller determines the sun's position by using photosensitive resistances to collect light intensity and control stepper motors to achieve photo electric tracking，n cloudy days，it collects clock chip PCF8583time information to calculate the current position of the sun and achieve the sun angle tracking.Experimental results show the solar tracking controller accurately tracks the sun in different weather conditions，improves received energy efficiency by30%and reaches the purpose of full use of solar energy.
上傳時間： 2013-10-15
上傳用戶：urgdil
介紹一種基于CAN總線的牽引變電站自動化系統通訊規約的設計，CAN通訊規約采用標準幀，報文采用主動發送和發送查詢兩種處理形式。該設計在城市輕軌與地鐵牽引變電站中的應用表明：可實現間隔層和通訊處理層的數據快速、可靠的交換，提高牽引變電站的安全性和穩定性 。 Abstract: This paper firstly presents a kind of design dealing with communicational protocol to the traction substation automation system based on CAN bus,and then comes up with the ideas that all frames of CAN communicational protocol should adopt the standard frame,and that messages be processed by two ways:sending initiatively and sending quiries.Subway and light rail application shows that the use of the CAN bus is possible to exchange data quickly and reliably between the layers of the middle and the communicational processing,hence to improve the safety and stability of traction substations.
上傳時間： 2013-11-07
上傳用戶：bs2005
在汽車發動機起動時，若發動機起動后起動機不能及時斷電，將會燒毀起動機或損壞飛輪齒環；若變速器不在空檔位置起動，則起動機的瞬間動力將使汽車位移，還可能引起交通事故和人身安全。為此介紹一種利用NXP P89LPC901單片機控制的汽車起動保護控制器，通過檢測汽車起動開關、變速箱檔位、發動機轉速，實現對汽車發動機起動過程檢測和保護。起動保護控制器在發動機起動過程中通過采用逐個關閉打開負載系統，解決汽車發動機過程中因起動電流大而對汽車電源的沖擊影響,延長了電瓶壽命。 Abstract: When the automotive engine is started, the engine start motor and flywheel gear may be damaged， even traffic accidents and personal safeties may be caused by wrong operation or other factors.In order to ensure the automotive engine can be started normally and safely,it is necessary that the protecting measures and methods are considered in the automotive electrical control system.This paper introduces a kind of the automotive engine starting protect controller based on NXP P89LPC901 MCU.The controller can protect the engine starting process by detecting the starter key switch,transmission stall and engine speed.Through the use of close and open load system,the controller can solve the impact on automotive power because of the high-current load in the process of the automobile engine starting, and extend battery life.
上傳時間： 2013-10-15
上傳用戶：mikesering
為滿足礦井安全生產要求，介紹了一種以AT89C51單片機為主控器，對環境空氣的溫度、有毒易燃氣體的濃度等進行檢測的監控系統。該系統配合外圍電路能實現對上述環境指標的控制并存儲相關數據與上位PC機通信。它采用硬件抗干擾和軟件抗干擾技術，以確保整個系統工作的準確性。 Abstract: In order to meet the needs of mine produce safety，a kind of intellignet mine ambient monotoring and control system based on AT89C51 is introduced.This system can detect the temperature of ambient of mine，the density of poisonous inflammable gas,combined external circuit.With its function part， this system can change above-mentioned elements.
上傳時間： 2013-11-10
上傳用戶：wendy15
在需要實時大量輸入漢字的顯示控制處理應用中，利用傳統單片機實現顯示控制的設計方法是較難實現的。帶漢字字庫的液晶模塊的使用使得小容量ROM單片機的大量漢字信息輸入與顯示成為可能。提出了針對漢字字庫編碼的二級索引拼音輸入檢索方法,介紹了以ST7920作為控制器的帶漢字字庫的液晶顯示模塊的接口方法及漢字顯示和控制原理，給出了通用計算機鍵盤在單片機中的串行接口，采用該技術可大大增強單片機的漢字輸入功能。為小容量ROM單片機的大批量漢字信息處理提供了一種漢字輸入解決方案。 Abstract: It is difficult to realize Chinese characters input method based on the embedded system by using the traditional design method of display control. It is possible to input and display Chinese characters based on the embedded system with the ROM of small content by using the LCD module with Chinese characters.Chinese characters input method of the quadric index recall in allusion to Chinese characters code is brought forward.The interface and the principle of Chinese characters display control based on the LCD module controlled with the ST7920 is introduced too.The serial interface of the computer keyboard in common use and the embedded system is given at the same time. It can enhance the embedded system function of Chinese characters input by using this technology, and provide a kind of Chinese characters input scheme for the embedded system with small capacity ROM.
上傳時間： 2013-11-19
上傳用戶：jhksyghr
針對當前安檢力學試驗機所能完成的試驗種類單一、自動化程度低等問題，提出一種以ATmega128單片機為核心控制器的安檢力學試驗機的設計。詳細闡述了該安檢力學試驗機各個組成部分的設計原理和方案，并且給出了各部分的軟件設計思想和操作流程。經過大量測試試驗表明：設計的安檢力學試驗機可以完成多達十余種的力學安檢試驗，完全符合相關國家標準，并且具有數據采集精度高、傳輸速度快、操作安全簡便等特點，實現了安檢設備的多功能化、數字化和自動化。 Abstract: Currently， many mechanical security testing machines have only one function. The degree of automation of them is low. To solve those problems， a new kind of mechanical security testing machine， using ATmega128 micro-controller as its core controller， has been advanced. It describes the components of the machine. The principles and the scheme in the designing processes are presented in detail， and the software architecture and the operation processes of each part are given. After having done many testing， we have reached the following conclusions: the mechanical security testing machine presented can do over ten mechanical security tests complying with related national standards. It has high data acquisition accuracy and high transmission speed. The operation of the machine is simple and safe. In general， this machine is a multi-functional， highly automatic， digitalized security testing device.
上傳時間： 2013-11-05
上傳用戶：a67818601
