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Voltage

基于開關電容技術的鎖定放大器設計

鎖定放大是微弱信號檢測的重要手段。基于相關檢測理論，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.

標簽： 開關電容鎖定放大器

上傳時間： 2013-11-29

上傳用戶：黑漆漆
Wide-input dc/dc modules offer

When a system designer specifies a nonisolated dc/dc powermodule, considering the needed input Voltage range isequally as important as considering the required performanceattributes and features. Generally, nonisolated moduleshave either a narrow or a wide input Voltage range. Narrowinputmodules typically have a nominal input Voltage of3.3, 5, or 12 V. For systems that operate from a tightlyregulated input bus—such as those that do not use batterybackup—a narrow-input module is often adequate sincethe input remains fairly stable.Offering greater flexibility, wide-input modules operatewithin a range of 7 to 36 V, which includes the popular12- or 24-V industrial bus. This enables a single module tobe used for generating multiple Voltages. These modulesare ideal for industrial controls, HVAC systems, vehicles,medical instrumentation, and other applications that usea loosely regulated distribution bus. In addition, systemspowered by a rectifier/battery charger with lead-acidbattery backup almost always require wide-input modules.System designers who choose power supplies may wantto take a close look at the latest generation of wide-inputdc/dc modules.

標簽： Wide-input modules offer dc

上傳時間： 2014-12-24

上傳用戶：dragonhaixm
基于8098單片機的SPWM變頻調速系統

　　數字控制的交流調速系統所選用的微處理器、功率器件及產生PWM波的方法是影響交流調速系統性能好壞的直接因素。在介紹了正弦脈寬調制(SPWM)技術的基礎上，設計了一種以8098單片機作為控制器，以智能功率模塊IPM為開關器件的變頻調速系統。通過軟件編程，產生正弦脈沖寬度調制波形來控制絕緣柵雙極晶體管的導通和關斷，從而達到控制異步電動機轉速的目的。實驗結果表明，該系統可調頻率調電壓，穩定度高，調速范圍寬，具有較強的實用價值　　Abstract: 　　AC variable speed with digital control systems used microprocessors， power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation Voltage， high stability， wide speed range， has a strong practical value.

標簽： 8098 SPWM 單片機變頻調速系統

上傳時間： 2013-11-14

上傳用戶：ynwbosss
C8051F020

HIGH SPEED 8051 μC CORE - Pipe-lined Instruction Architecture; Executes 70% of Instructions in 1 or 2 System Clocks - Up to 25MIPS Throughput with 25MHz System Clock - 22 Vectored Interrupt Sources MEMORY - 4352 Bytes Internal Data RAM (256 + 4k) - 64k Bytes In-System Programmable FLASH Program Memory - External Parallel Data Memory Interface – up to 5Mbytes/sec DIGITAL PERIPHERALS - 64 Port I/O; All are 5V tolerant - Hardware SMBusTM (I2CTM Compatible), SPITM, and Two UART Serial Ports Available Concurrently - Programmable 16-bit Counter/Timer Array with 5 Capture/Compare Modules - 5 General Purpose 16-bit Counter/Timers - Dedicated Watch-Dog Timer; Bi-directional Reset CLOCK SOURCES - Internal Programmable Oscillator: 2-to-16MHz - External Oscillator: Crystal, RC, C, or Clock - Real-Time Clock Mode using Timer 3 or PCA SUPPLY Voltage ........................ 2.7V to 3.6V - Typical Operating Current: 10mA @ 25MHz - Multiple Power Saving Sleep and Shutdown Modes 100-Pin TQFP (64-Pin Version Available) Temperature Range: –40°C to +85°C

標簽： C8051F020

上傳時間： 2013-10-12

上傳用戶：lalalal
基于89C52的二極管特性測試器的設計

　　利用單片機具有的智能程序控制的特點，設計了基于STC89C52單片機的"二極管特性測試器"，可對二極管一般特性進行快速測試。通過穩定線性電流源給二極管加載恒定電流，然后由高精度模數轉換器測試其壓降，以此為基礎可判斷二極管好壞、檢測二極管極性和測試二極管伏安特性等，避免了用萬用表測試只能測得極性而不知其特性這一缺點。可用于電子設計制作過程中對二極管進行快速測試，以確定被測二極管是否滿足電路的設計要求。　　Abstract: 　　By making good use of the intelligent control function of the Micro Controller Unit (MCU)， the diode trait tester was designed based on the STC89C52，which could be used to test the trait of a diode rapidly. By loading constant current to diode through the stable linear current source， and measuring the Voltage drop of the diode by high-precision analogue-to-digital converter (ADC)， it can judge whether the diode is good or not， distinguish the polarity of the diode， and test the trait that the diode， which can avoid the fault of using a multimeter can only measure the polarity but not the trait. This device can be used to test the trait of a diode quickly，and to make sure that whether a diode can be used in the electronic design or not.

標簽： 89C52 二極管特性測試器

上傳時間： 2013-11-13

上傳用戶：assef
常用PIC系列單片機速查表

常用PIC系列產品特性一覽表器件存儲器類型字數 EEPROM 數據存儲器 RAM I/O 引腳數 ADC （-Bit）比較器運放定時器/WDT 串行接口最高速度 MHz 封裝 PDIP /SOIC ICSP CCP / ECCP 輸出電流 (per I/O) 振蕩器頻率 (MHz) 參考電壓 VREF LCD PWM 堆棧深度 High Voltage Wakeup On Change PIC16C432 OTP 2048x14 128 12 2 1-8bit/1-WDT 20 20 √ 25 mA 4 0 0 PIC16C433 OTP 2048x14 128 6 4/8 1-8bit/1-WDT 10 18 √ 25 mA 0 0 PIC16C505 OTP 1024x12 72 12 1-8bit/1-WDT 20 14 √ 25 mA 4 0 0 PIC16C54 OTP 512x12 25 12 1-8bit/1-WDT 20 18/20 20 mA 0 0 PIC16C54A OTP 512x12 25 12 1-8bit/1-WDT 20 18/20 20 mA 0 0 PIC16C54C OTP 512x12 25 12 1-8bit/1-WDT 40 18/20 20 mA 0 0 PIC16C55 OTP 512x12 24 20 1-8bit/1-WDT 20 28 20 mA 0 0 PIC16C554 OTP 512x14 80 13 1-8bit/1-WDT 20 18/20 √ 25 mA 0 0 PIC16C558 OTP 2048x14 128 13 1-8bit/1-WDT 20 18/20 √ 25 mA 0 0 PIC16C55A OTP 512x12 24 20 1-8bit/1-WDT 40 28 20 mA 0 0 PIC16C56 OTP 1024x12 25 12 1-8bit/1-WDT 20 18/20 20 mA 0 0 PIC16C56A OTP 1024x12 25 12 1-8bit/1-WDT 40 18/20 20 mA 0 0 PIC16C57 OTP 2048x12 72 20 1-8bit/1-WDT 20 28 20 mA 0 0 PIC16C57C OTP 2048x12 72 20 1-8bit/1-WDT 40 28 20 mA 0 0 PIC16C58B OTP 2048x12 73 12 1-8bit/1-WDT 40 18/20 20 mA 0 0 PIC16C620 OTP 512x14 80 13 2 1-8bit/1-WDT 20 18/20 √ 25 mA √ 0 0 PIC16C620A OTP 512x14 96 13 2 1-8bit/1-WDT 40 18/20 √ 25 mA √ 0 0 PIC16C621 OTP 1024x14 80 13 2 1-8bit/1-WDT 20 18/20 √ 25 mA √ 0 0 PIC16C621A OTP 1024x14 96 13 2 1-8bit/1-WDT 40 18/20 √ 25 mA √ 0 0 PIC16C622 OTP 2048x14 128 13 2 1-8bit/1-WDT 20 18/20 √ 25 mA √ 0 0 PIC16C622A OTP 2048x14 128 13 2 1-8bit/1-WDT 40 18/20/40 √ 25 mA √ 0 0 PIC16C62A OTP 2048x14 128 22 2-8bit/1-16bit/1-WDT I²C/ SPI 20 28/ √ 1 25 mA 1 0 0 PIC16C62B OTP 2048x14 128 22 2-8bit/1-16bit/1-WDT I²C /SPI 20 28 √ 1 25 mA 1 0 0 PIC16C63 OTP 4096x14 192 22 2-8bit/1-16bit/1-WDT USART/I²C /SPI 20 28 √ 2 25 mA 2 0 0 PIC16C63A OTP 4096x14 192 22 2-8bit/1-16bit/1-WDT USART/I²C/SPI 20 28 √ 2 25 mA 2 0 0 PIC16C642 OTP 4096x14 176 22 2 1-8bit/1-WDT 20 28 √ 25 mA √ 0 0 PIC16C64A OTP 2048x14 128 33 2-8bit/1-16bit/1-WDT I²C /SPI 20 40/44 √ 1 25 mA 1 0 0 PIC16C65A OTP 4096x14 192 33 2-8bit/1-16bit/1-WDT USART/I²C/SPI 20 40/44 √ 2 25 mA 2 0 0 PIC16C65B OTP 4096x14 192 33 2-8bit/1-16bit/1-WDT USART/I²C/SPI 20 40/44 √ 2 25 mA 2 0 0 PIC16C66 OTP 8192x14 368 22 2-8bit/1-16bit/1-WDT USART/I²C/SPI 20 28 √ 2 25 mA 2 0 0 PIC16C662 OTP 4096x14 176 33 2 1-8bit/1-WDT 20 40/44 √ 25 mA √ 0 0 PIC16C67 OTP 8192x14 368 33 2-8bit/1-16bit/1-WDT USART/I²C /SPI 20 40/44 √ 2 25 mA 2 0 0 PIC16C71 OTP 1024x14 36 13 4/8 1-8bit/1-WDT 20 18 √ 25 mA 0 0 PIC16C710 OTP 512x14 36 13 4/8 1-8bit/1-WDT 20 18/20 √ 25 mA 0 0 PIC16C711 OTP 1024x14 68 13 4/8 1-8bit/1-WDT 20 18/20 √ 25 mA

標簽： PIC 單片機速查

上傳時間： 2013-10-12

上傳用戶：xjy441694216
基于單片機的顏色自適應識別電路

　　為解決電致變色器件的顏色變化受外界環境顏色控制的問題，設計了一種基于單片機的便攜式顏色自適應識別電路。與傳統顏色識別電路相比較，該電路利用數字式的顏色傳感器來獲取外界環境顏色，產生的數字顏色信號易于單片機進行處理。在電路中，下位機部分主要負責獲取電致變色器件變色參數及控制電致變色器件的顏色變化;而上位機部分主要負責把下位機獲取的電致變色器件變色參數進行電壓到顏色的曲線擬合，并通過藍牙通信把擬合曲線參數傳遞給下位機。結果表明，該電路能自動根據環境顏色提供-4~4 V范圍步進為0.1 V的電壓來驅動電致變色器件的顏色顯示，與傳統的顏色識別電路設計相比，識別的精度和速度都得到了明顯改善。　　Abstract: 　　In this paper， a portable adaptive circuit for color identification(PACCI) based on MCU was designed. Compared to the traditional color identification circuit， the PACCI adopts digital sensor to detect the color data from external environment and further generate digital color data， which can be processed easily by MCU. In PACCI， the slave is mainly responsible for detecting the color parameters of the corresponding elcreochromic device and further driving it. For the master， which is mainly responsible for the color curve fitting based on the parameters of the electrochromic device， and transmits the fitting parameters to the slave through the bluetooth device. The results show that the PACCI can provide the basis Voltage range from -4V to 4V automatically based on the colors of external environment with step as 0.1V to drive the corresponding electrochromic device. Compared to the traditional color recognition circuit， the recognition accuracy and speed of PACCI have been improved significantly.

標簽： 單片機識別電路

上傳時間： 2013-11-09

上傳用戶：franktu
基于MSP430F1611單片機的音頻信號分析儀設計

　　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.

標簽： F1611 1611 430F MSP

上傳時間： 2013-12-11

上傳用戶：jasonheung
基于MAX7219的LED數碼顯示驅動電路設計

　　現有基于MAX7219芯片的數碼管驅動電路只適用于小尺寸LED，為擴展其使用范圍，在介紹動態顯示芯片MAX7219功能的基礎上，提出了一個基于該芯片的8位高亮度8英寸數碼管驅動電路。電路保留了MAX7219芯片的功能強大、編程簡單等優點，通過74LS273鎖存器和ULN2803達林頓驅動器，實現了對任意大尺寸數碼管提供較高電壓和電流驅動的靜態顯示，并亮度可調。　　Abstract: 　　The existing display-driving circuit based on MAX7219 was only applicable to small-size LED. To expand its use, based on the function introduction of dynamic display chip MAX7219, a display-driving circuit for high-brightness 8-bit LED with the size of 8-inch was proposed. The advantages of MAX7219 were retained, such as powerful function and simple programming. Static display with adjustable brightness for large-size LED with higher Voltage and current was achieved with the help of 74LS273 and ULN2803.

標簽： 7219 MAX LED 數碼顯示

上傳時間： 2013-10-23

上傳用戶：31633073
基于PIC16C71的數字水溫配制閥的設計

　　設計了一種基于PIC16C71單片機的數字水溫配制閥。該配制閥采用NTC熱敏電阻作溫度傳感器，與固定電阻組成簡單分壓電路作為水溫測量電路，利用PIC16C71單片機內置的8位A/D轉換器把熱敏電阻上的模擬電壓轉換為數字量，PIC16C71單片機控制直流電機驅動混水閥調節冷熱水的混合比例實現水溫調節。給出了控制電路圖，對水溫測量電路的參數選擇和測溫精度作了詳細討論。實驗和分析表明，選用阻值較大的NTC熱敏電阻和分壓電阻可較好地解決熱敏電阻因功耗較大造成的熱擊穿問題。　　Abstract: 　　A digital valve for controlling water temperature based on PIC16C71 was presented in this paper.A bleeder circuit which consisted of a NTC thermistor as temperature sensor and a fixed resistance was designed as water temperature measuring circuit.The analog Voltage on the thermistor was converted into digital signal by a 8-bit A/D converter embedded in PIC16C71. Based on the digital signal， the MCU PIC16C71 drived the valve by a DC motor to adjust the water temperature through adjusting the proportion of hot water and cold water.The circuit diagram of controller was given，the principle，the component parameters and the accuracy of measuring temperatures were also dissertated in detail. It was found by experiment and analysis that thermal breakdown of thermistor caused by high power could be solved by selecting thermistor and fixed resistance with high impedance value.

標簽： PIC 16C C71 16

上傳時間： 2013-11-08

上傳用戶：Yue Zhong