为了解决磁放大器性能测试过程中,需要对其供给不同数值恒定电流的问题,设计了一种基于DAC7512和单片机的数控恒流源系统。该系统采用AT89C51作为主控器件,将计算机发送的电流控制字命令转换为D/A转换器控制字,通过模拟SPI通信接口,写D/A控制字到DAC7512,从而控制其输出相应数字电压值,经差动缩放电路、电压/电路变换电路和功率驱动电路,最后输出恒定电流。实验结果表明,恒流源输出电流调节范围为-45~+45 mA、精度为±0.1 mA,分辨率达0.024 4 mA,具有应用灵活,外围电路简单,可靠性高的特点。该数控直流恒流源也可为相关产品的测试系统研发提供参考。 Abstract: In order to solve the need to supply different values constant current for the magnetic amplifier in testing process, numerical control constant current source system was designed based on DAC7512 chip and microcontroller technology. The system used the AT89C51 as the main chip, which can convert the current control word from computer into to D/A control words. And the system wrote D/A control word into the DAC7512 chip to control the output voltage value by the SPI communication interface, which can output corresponding constant current figures by scaling circuit, the V/I converter and power drive circuit. Experimental results show that the current source output current adjustment range is -45~+45mA, accuracy is ± 0.1mA, and resolution ratio is 0.024 4mA
上传时间: 2014-12-27
上传用户:invtnewer
为降低成本和解决现有膜片钳放大器系统中PC机的干扰问题,研究了一种基于单片机的膜片钳放大器小系统。该系统采用ADI公司生产的ADuC841作为控制核心,并且配置相应的液晶显示模块LCM3202401。模拟电路部分采用高输入阻抗的AD8627实现微电流信号的采集,并由后级电路进行信号的放大和电阻电容的补偿。它具有硬件电路简单、体积小、使用方便的特点。既可以单独作为小系统实现采集和显示,也可以通过红外方式和PC机进行通讯,在PC机上进行信号的处理。 Abstract: In order to reduce cost and resolve the interferential problem with PC in existing patch clamp amplifiers, a small patch clamp amplifier system design based on microcontroller is studied. It adopts a new high performance microconverter ADuC841 by the ADI as the control core in the system, configuring a liquid crystal module LCM3202401. In the analog circuit, AD8627 with high input impedance is used to detect the low current,signal magnification, as well as resistance and capacitance compensation are accomplished by subsequent circuits. It has the advantage of simple hardware circuit design, small volume and convenient operation. It can either be used as an independent system to measure and show signal detected or transmit to PC by infrared ray.
上传时间: 2013-11-06
上传用户:yy_cn
利用AT89C51型单片机定时和中断功能,配以LM386型音频功率放大器,构成了作息号音自动播放器,为学校和机关管理提供方便。 Abstract: Using timing and interrupt function of the AT89C51 single-chip microcomputer and the LM386 audio power amplifier.It is constituted the automatic bugle player.This player facilitates the institution and the school daily management.
上传时间: 2013-10-10
上传用户:wivai
Features• Complete DTMF Receiver• Low power consumption• Internal gain setting amplifier• Adjustable guard time• Central office quality• Power-down mode• Inhibit mode• Backward compatible withMT8870C/MT8870C-1Applications• Receiver system for British Telecom (BT) orCEPT Spec (MT8870D-1)• Paging systems• Repeater systems/mobile radio• Credit card systems• Remote control• Personal computers• Telephone answering machine
上传时间: 2013-11-20
上传用户:mpquest
NEC 16位MCU参考手册 The 78K0R/IC3 is a 16-bit single-chip microcontroller that uses a 78K0R CPU core and incorporates peripheral functions, such as ROM/RAM, a multi-function timer, a multi-function serial interface, an A/D converter, a programmable gain amplifier (PGA), a comparator, a real-time counter, and a watchdog timer.
上传时间: 2013-11-02
上传用户:努力努力再努力
全遥控6声道AV机的汇编程序:;;;;;;;;;;;;;;;;;;;6CH AMPLIFIER;;;;;;;;;;;;;;;;;----脚位定义-----;;;;;;;;;;;;;;;;;;;6CH AMPLIFIER;;;;;;;;;;;;;;;;;----脚位定义----- PT6311_CLK EQU P3.4PT6311_STB EQU P3.5PT6311_DATA EQU P3.3 UP EQU P3.1DOEN EQU P3.0 PT2313_DATA EQU P0.7PT2313_CLK EQU P2.7 AC3 EQU P2.6 ;(控制4053的信号) M62429_DA EQU P2.3 ;(SURL/R)M62429_CK EQU P2.4 M62429_CK1 EQU P2.5 ;(C/BW) M62429_CK3 EQU P0.0 ;(ECHO,MVOL)M62429_DA3 EQU P1.7M_DELAY1 EQU P0.1M_DELAY2 EQU P0.2 AD_OUT BIT P0.5AD_IN BIT P0.6 ;----片内RAM定义--------GIF_SIGN EQU 40H ; 动画进程标记(=1,走过场字幕 )GIF_TIME1 EQU 41H ; 动画跑字的时间间隔速度GIF_LONG EQU 42H ; 动画字幕的长度 DISP_BUFFER EQU 43H ; 显示缓冲区地址指针DISP_INDEX EQU 44H ; PT6311片内地址指针
上传时间: 2013-10-19
上传用户:fac1003
计算机应用中,有时需处理的信息不是数字量,而是一些随时间连续变化的模拟量,甚至是一些非电量,如温度、压力、速度等。模拟量的存储处理困难。首先将非电的模拟信号变成与之对应的模拟电信号,这要通过各种传感器来完成。计算机可处理的信息均是数字量(电脉冲信号)1和0,必须把要处理的模拟电量转换成数字化的电信号,这需要模拟(Analog)与数字(Digital)转换电路。数字到模拟转换:(Digital to Analog Convert, D/A) D/A转换电路是模拟电路加上电子开关。D/A转换电路的核心是一个运算放大器。运算放大器的特性:(Operation Amplifier) K->无穷大, V和->0 传递函数:V0 = -Vi * R0/Ri Ii->0, I和=If梯形R-2R电阻网络D/A转换器Ki受一个8位二进制代码控制 某位为1,对应开关K倒向右边; 某位为0,对应开关K倒向左边。Ki不论倒向哪边,均为接地VA-VH 的电位为: VREF,1/2VREF,..1/128VREFVO= -VREF *(1/2K7+1/4K6+…+1/256K0)V0= -(0-255/256)VREF 8位D/A转换器DAC0830系列器件国家半导体公司(NS)产品,0830、0831、0832。R-2R梯形电阻网络D/A转换器,双缓冲结构。单电源、低功耗、电流建立时间1uS。与微计算机接口方便。8位D/A转换器DAC0830系列器件ILE: 输入锁存允许; WR1#: 加载IN REG; WR2#: 加载DAC REG; XFER#: IN REG传到DAC REG; Iout1,Iout2: 外接OA输入; Rfb: 反馈电阻接OA输出; VREF: 参考电源,控制输出电压变化范围。
标签: AD转换
上传时间: 2013-10-16
上传用户:lu2767
第一讲 光纤的分类 一, 光纤的分类 光纤是光导纤维(OF:Optical Fiber)的简称。但光通信系统中常常将 Optical Fibe(光纤)又简化为 Fiber,例如:光纤放大器(Fiber Amplifier)或光纤干线(Fiber Backbone)等等。有人忽略了Fiber虽有纤维的含义,但在光系统中却是指光纤而言的。因此,有些光产品的说明中,把fiber直译成“纤维”,显然是不可取的。 光纤实际是指由透明材料作成的纤芯和在它周围采用比纤芯的折射率稍低的材料作成的包层所被覆,并将射入纤芯的光信号,经包层界面反射,使光信号在纤芯中传播前进的媒体。 光纤的种类很多,根据用途不同,所需要的功能和性能也有所差异。但对于有线电视和通信用的光纤,其设计和制造的原则基本相同,诸如:①损耗小;②有一定带宽且色散小;③接线容易;④易于成统;⑤可靠性高;⑥制造比较简单;⑦价廉等。
上传时间: 2013-10-27
上传用户:llandlu
The AN10 begins with a survey of methods for measuring op amp settling time. This commentary develops into circuits for measuring settling time to 0.0005%. Construction details and results are presented. Appended sections cover oscilloscope overload limitations and amplifier frequency compensation.
上传时间: 2013-11-14
上传用户:JIMMYCB001
在Multisim 10软件环境下,设计一种由运算放大器构成的精确可控矩形波信号发生器,结合系统电路原理图重点阐述了各参数指标的实现与测试方法。通过改变RC电路的电容充、放电路径和时间常数实现了占空比和频率的调节,通过多路开关投入不同数值的电容实现了频段的调节,通过电压取样和同相放大电路实现了输出电压幅值的调节并提高了电路的带负载能力,可作为频率和幅值可调的方波信号发生器。Multisim 10仿真分析及应用电路测试结果表明,电路性能指标达到了设计要求。 Abstract: Based on Multisim 10, this paper designed a kind of rectangular-wave signal generator which could be controlled exactly composed of operational amplifier, the key point was how to implement and test the parameter indicators based on the circuit diagram. The duty and the frequency were adjusted by changing the time constant and the way of charging and discharging of the capacitor, the width of frequency was adjusted by using different capacitors provided with multiple switch, the amplitude of output voltage was adjusted by sampling voltage and using in-phase amplifier circuit,the ability of driving loads was raised, the circuit can be used as squarewave signal generator whose frequency and amplitude can be adjusted. The final simulation results of Multisim 10 and the tests of applicable circuit show that the performance indicators of the circuit meets the design requirements.
上传时间: 2014-01-21
上传用户:shen007yue