模转换

First it produces the pulse signal by the multivibratorwhich is consisted of 555 timer and send in the detecting coil to form the alternating magnetic field, then it asopts UGN3503 linear half-effect as prode to the magnetic field change into the voltage signal change,after enlargement electric circuit and peak value examination electric circuit,the signal be treated to send into ADC0809 modulus converter change moduluses, then the digital signal after the modulus converter is changed is sent into AT89C51one-chip computers afterwards, after the digital filter, AT89C51one-chip computers afterwards compares the data to the reference voltage and judges whether to have detected the metal and alarm.

这个系统是以AT89C51单片机为核心，首先由555定时器构成多谐振荡器产生脉冲信号送入探测线圈以形成交变磁场，然后经过线性霍尔器件UGN3503将磁场变化转换为电压信号的变化，经过放大电路和峰值检测电路，经数模转换之后输入到单片机中，由单片机对数据进行软件滤波之后，与基准值比较之后，判断是否存在金属和报警显示。

To keep away from digital distortion caused by analog conversion,"Boutique Recording" applies APOGEE Analog to Digital Converter System in pre-recording, adopts Hi-End Prism Sound Digital to Analog Converter System during post mix and master disposal processes. In a word,"Boutique Recording" minimizes the distortion rate, and maintains the unique spirit of analog music.

为避免后期缩混时过多数字设备所造成的数码味，录音师坚持在前期录音与母带处理过程中使用传奇的模拟设备，在现场录音的同时进行立体声混音工作，为了避免模数转换时所造成的数字失真，达人艺典在前期录音中采用APOGEE模数转换系统，后期缩混及母带制作采用顶级HI-END厂牌Prism Sound数模转换系统，将失真率减到最低，保持独有的模拟音乐味道。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

This high voltage electrostatic precipitation controller has 7 channels of analog input,2 channels of analog output, 12 digital inputs and 16 digital outputs. The analog input includes primary current, secondary current, primary voltage, secondary voltage, etc. Controller uses MAX 187 as the A/D converter, which ensure the sampling speed and the conversion precision in the same time. The processor unit is RCM2250 module. Rabit 2000 processor, a 128K SRAM and a 256K Flash Rom are integrated in RCM2250, which improves the performance of pricipitation controller. MAX504 is used to produce the 4~20mA current output.

模拟量输入采集的信号有升压变压器一次电流、一次电压、二次电流、二次电压等，采用12位逐次比较式A/D转换器MAX187，兼顾采样速率和转换精度；中央处理单元采用以8位嵌入式处理器Rabbit2000为基础的RCM2250模块，外扩128KSRAM和256K Flash ROM，内部资源丰富，提高了控制器的整体性能；模拟量输出采用内带基准源的10位电压输出数模转换器MAX504，实现了标准4～20mA电流信号输出；控制器通过控制算法在相应开关量点上输出可控硅的触发脉冲。

The method comprises the steps of: constructing a testing system which inputs digital codes and outputs simulated values of the analog-digital converter; obtaining a comparison table which is output through inputting responded simulated values of different digital codes from 0 to 2N-1 of the analog-digital converter; calculating to obtain an integration non-linear error comparison table corresponding to different digital code input of the analog-digital converter; compensating integration non-linear errors of the analog-digital converter through a hardware compensating method of adding a subtracter; and obtaining accurate analog-digital converter output.

搭建数模转换器的数字码输入-模拟值输出的测试系统；获得数模转换器从0到2 N -1的不同数字码输入响应的模拟值输出的对照表；计算得到数模转换器相应于不同数字码输入的积分非线性误差的对照表；通过加入减法器的硬件补偿方法，补偿数模转换器的积分非线性误差，获得准确的数模转换器输出。

, [Chapter 5 of analog-digital conversion and digital-analog conversion], Chapt...

[第4章单片机功能应用]，[第5章模数转换与数模转换]，[第7章人机接口技术]，[第8章通信接口技术]。

The working principle of a novel short st roke linear DC motor wit h permanent magnet s is presented. Mixed digital - analog cont rol approach based on DSP ( TMS320L F2407A) is proposed. Displacement detecting and cont rol technique are discussed. Displacement detecting circuit s , digital - to - analog converter (DAC7641) expanded circuit s and cont rol software are given.

阐述了一种新研制的短行程永磁直流直线电机的工作原理，提出了基于DSP ( TMS320L F2407A)的短行程直流直线电机数、模混合伺服控制系统方案，重点对直线电机的位置检测及控制技术进行了研究，给出了DSP 控制器的位置检测接口电路、16 位双极性数模转换器(DAC7641)的扩展电路和控制软件的实现方法。

This paper presents the Proteus software under a micro-controller board simulation method, and gives a digital-to-analog converter, analog-to-digital conversion、ISP programming、numeral clock 、real-time digital clock ﹑ Lantern experimental keyboard ﹑lattice LED ﹑ Relay, voice and other tenets of the hardware modules and software flow chart.

本文介绍了在Proteus软件下实现了一套单片机实验板的仿真方法，并给出了数模转换、模数转换﹑ISP编程﹑数字钟﹑实时时钟、键盘﹑彩灯实验﹑点阵LED显示屏﹑继电器、语音等模块的硬件原理及软件流程图。

This paper presents the Proteus software under a micro-controller board simulation method, and gives a digital-to-analog converter, analog-to-digital conversion、ISP programming、numeral clock 、real-time digital clock ﹑ Lantern experimental keyboard ﹑lattice LED ﹑ Relay, voice and other tenets of the hardware modules and software flow chart.

论文编号：JD607 包括开题报告，任务书，外文翻译，论文字数：10522，页数：46本文介绍了在Proteus软件下实现了一套单片机实验板的仿真方法，并给出了数模转换、模数转换﹑ISP编程﹑数字钟﹑实时时钟、键盘﹑彩灯实验﹑点阵LED显示屏﹑继电器、语音等模块的硬件原理及软件流程图。

The digital users signals comprising in-phase component and quadrature component are converted to analog baseband signals by digital-to-analog converters 104 and 114, which are followed by lowpass filters 106 and 116 for removing harmonics at unwanted frequencies.

包括同相分量和正交分量的数字用户信号通过数模转换器104和114转换成模拟基带信号，在数模转换器104和114的后面具有低通滤波器106和116，低通滤波器106和116用于去除在不期望频率处的谐波。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。