基于ATmega16单片机的实时温度采集与分析系统

温度是工农业生产中很重要的的参数,它直接影响到产品的质量与性能。提出了一种基于ATmega16单片机与温度传感器相结合的实时温度采集与分析系统。本系统介绍了以ATmega16单片机为核心,以及自动化控制装置GTJ4-10A固态继电器和数字温度传感器DS18B20,报警与指示电路等,在分析中基于MFC的软件处理。其中包括温度曲线的绘制,以及温度值的保存,显示历史记录等。在经过烧水温度的测试,该系统稳定可靠便于分析。温度误差0.5℃,可以满足工农业生产的要求     

应用机器视觉精确检测工件尺寸的研究

本文在介绍机器视觉检测系统的组成和工件尺寸检测原理的基础上,以高精度尺寸的标准块为例,详细介绍了工件图像滤波,边缘检测和亚像素边缘提取,并对亚像素边缘特性和规律进行了简单的分析.实验检测结果表明,对不超过40mm的工件,尺寸检测误差不超过0.1mm;改进系统测量方法后,检测误差不超过0.01mm.     

智能里程表检测仪硬件设计

现在市场上的里程表样式多种多样,但是很多里程表存在着汽车总里程数和车速不准确的问题,这就需要进行里程表的检测。该文提出了一种里程表检测仪的硬件设计,该设计采用ATmega16为核心的单片机系统,用变频器控制速度,实现了对不同调速比的里程表的检测。该里程表检测仪的系统电路简单可靠,用它来检测里程表方便且高效。     

基于单片机的螺旋式自动称重系统设计

为了解决当前自动称量装置成本高且体积大难于推广的问题,本文设计了一种以单片机ATmega16为控制核心的螺旋式自动计量称量系统。该系统由直流电机控制模块,人机交互模块,采样转换模块构成,本装置成本低、可靠性高,实用性强且易于推广。     

基于耦合技术的单色光谱吸收法检测甲烷气体浓度

针对电子检测装置在甲烷气体浓度检测时存在易燃易爆等安全隐患,本文提出了一种基于光纤耦合技术的单色光谱吸收法检测甲烷气体浓度的方案。给出了单色光源的选择依据,设计了基于光纤耦合技术的单色光谱吸收法检测装置,提出了应用Matlab对甲烷气体浓度与输出电压两组数据进行线性拟合。通过输出电压预测出甲烷气体浓度,并检测了预测值与真实值的误差。实验结果表明,将光纤耦合技术应用于单色光谱吸收法检测甲烷气体浓度,可以在无电力介入的情况下对甲烷气体浓度进行实时检测,误差不超过2%。     

基于ATmega8的大功率直流电机控制系统

本系统采用ATmega8单片机为核心控制器,运用PWM控制H桥的技术,设计具有将电源实现了26V～180V的电压变换,转速检测、电流检测的直流电动机的双闭环负反馈控制算法,并给出程序流程图。     

基于TSIC506的高精度温度检测系统的设计

以ATmega16单片机为控制核心,利用数字化温度传感器TSIC506实现高精度温度检测系统。论述了该系统的硬件组成和软件设计,给出了系统总体结构及相应的ATmega16单片机温度测量程序。实际应用表明,该温度检测系统具有结构简单、成本低、稳定实用等特点,可根据不同需要应用于多种工农业温度检测领域。     

基于有源功率因数校正的高功率因数电源设计

构建有源功率因数校正（APFC）的高功率因数直流电源。该系统采用TI公司专用APFC整流控制芯片UCC28019作为控制核心,构成电压外环和电流内环的双环控制。其中内环电流环作用是使网侧交流输入电流跟踪电网电压的波形与相位;外环电压环为输出直流电压控制环。外环电压调节器的输出控制内环电流调节器的增益,使输出直流电压稳定。系统采用ATmega16单片机进行监控,完成输出电压的可调以及输入功率因数、输出电压、输出电流等的实时测量与显示和输出过流保护等功能。实测表明,系统性能指标完全达到或超过设计要求。     

智能侧滑仪

文章介绍汽车侧滑仪的检测原理，硬件结构以及软件配置。本仪器是检测机动车辆安全技术指标的有力手段。     

基于ATmega16单片机的数显电压表设计

针对测试仪器内部直流电平检测的需要,设计了一款以ATmega16为核心,结合电阻分压网络以及反相求和电路的数显电压表。用单片机自带的十位内部ADC进行模拟数据的采集和转换,设计软件精度校准的方法实现对-19.9~+19.9 V正负量程范围内直流电平的精确测量,并用三位数码管显示,超过设定阈值产生报警。实际测试结果表明,该系统误差不超过0.1 V,具有测量精度高、成本低、性能可靠、显示清晰等优点,有着很好的实用价值。     

基于DS18B20的室内智能温度控制系统设计

对于一些特定的室内农业和工业生产,提出了一种DS18B20温度传感器和ATmage8单片机结合的智能温度控制系统。该系统主要可分为上位机系统和下位机系统,上位机设定温度范围并控制下位机。ATmage8单片机通过DS18B20采集温度信号,处理后将温度值与上位机设定阈值作比较。单片机控制加热模块的工作,并且通过串口传给上位机显示当前温度。在经过实际的测试,该系统的性能稳定,误差控制在0.5℃,满足了小面积的室内应用。     

基于组合线结构光的涂胶质量检测系统设计

涂胶作为汽车生产中的重要环节,其质量好坏直接影响着整个汽车的安全性能。针对当前涂胶检测技术存在的精度低、误判率高、容易出现检测盲区等问题,研究了基于线结构光的汽车涂胶质量三维检测技术。重点分析了线结构光投射模式的选择、单目线结构光测量方法存在检测盲区两个难点问题,由此制定了涂胶检测系统的整体设计方案。以胶体宽度和厚度作为评价涂胶质量的标准,提出利用三个线结构光传感器组合测量的方法对胶体进行全方位的非接触测量。根据系统的性能指标对关键设备进行了选型,搭建了涂胶质量检测系统硬件平台,研究了胶体颜色和涂胶量对测量误差的影响,并进行了实验验证。     

一种恒流源驱动的高精度温度测量系统设计

为提高温度测量精度,利用REF200提供的0.4mA恒定电流驱动串联的四线制温度传感器PT1000和精密电阻,在传感器和精密电阻两端分别提取电压信号并对其进行调理,通过高精度AD7712对所得到的电压信号进行放大和A/D转换,设计了一种高精度温度测量系统。为了减小高精度温度测量中铂电阻非线性所引起的误差,在上位机中对数字信号进行了最小二乘法算法处理。测试结果表明,该系统稳定可靠,其随机误差和系统误差均小于0.1℃,实现了高精度温度测量。     

A self-tuning DVS processor using delay-error detection and correction

In this paper, we present a dynamic voltage scaling (DVS) technique called Razor which incorporates an in situ error detection and correction mechanism to recover from timing errors. We also present the implementation details and silicon measurements results of a 64-bit processor fabricated in 0.18-/spl mu/m technology that uses Razor for supply voltage control. Traditional DVS techniques require significant voltage safety margins to guarantee computational correctness at the worst case combination of process, voltage and temperature conditions, leading to a loss in energy efficiency. In Razor-based DVS, however, the supply voltage is automatically reduced to the point of first failure using the error detection and correction mechanism, thereby eliminating safety margins while still ensuring correct operation. In addition, the supply voltage can be intentionally scaled below the point of first failure of the processor to achieve an optimal tradeoff between energy savings from further voltage reduction and energy overhead from increased error detection and correction activity. We tested and measured savings due to Razor DVS for 33 different dies and obtained an average energy savings of 50% over worst case operating conditions by scaling supply voltage to achieve a 0.1% targeted error rate, at a fixed frequency of 120 MHz.     

飞机供电系统频率瞬变检测算法研究

频率瞬变是飞机供电系统的一个重要瞬态参数,采用示波器进行抓取的方法可以得到电压值但是难以分析频率值.为实现对频率瞬变过程的快速检测与显示,基于LabVIEW采用数据拟合、时间补偿等方法设计了一种频率瞬变检测算法,在发生频率瞬变时给出文本告警并对瞬变过程进行存储和复现.利用测试电源的输出标准电压信号来验证该算法,其测试误...     

Selection of spreading sequences for direct-sequencespread-spectrum communications over a doubly selective fading channel

Error probabilities are evaluated for direct-sequence spread-spectrum communications over channels with doubly selective fading. The error probability for such a system depends on the spreading sequence, the autocorrelation function of the fading process, and the receiver signal-to-noise ratio. The focus of this paper is on the effect of the spreading sequence on the performance of differentially coherent detection of binary direct-sequence spread-spectrum signals using a correlator receiver. It is shown that significant performance differences result from different choices of spreading sequence. It is also shown that, given a moderate range of delay and Doppler spreads, sequences can be found which yield low bit error probabilities over the entire range. These are found to be robust with respect to a variety of shapes for the channel autocorrelation function and the full range of signal-to-noise ratios     

The effects of sequence selection on DS spread spectrum withselective fading and Rake reception

Error probabilities are evaluated for direct-sequence spread-spectrum communications and Rake reception over channels with doubly selective fading. The error probability for such a system depends on the spreading sequence, the autocorrelation function of the fading process, the received signal-to-noise ratio, and the number of taps in the Rake receiver. The focus of the paper is on the effect of the spreading sequence on the performance of each of two systems. One system employs noncoherent detection of differentially-encoded binary direct-sequence spread-spectrum signals and a post-detection diversity-combining Rake receiver which uses equal-gain combining. The other system employs coherent detection of binary direct-sequence spread-spectrum signals and a post-detection diversity-combining Rake receiver with perfect gain estimates for the channel. A simple sequence selection criterion is introduced, and the sensitivity of the performance of the system to the choice of the spreading sequence is examined. It is shown that significant performance differences result from different choices of the spreading sequence. It is also shown that, given a moderate range of delay spreads, sequences can be found that yield low bit error probabilities over that range. These are found to be robust with respect to the delay spectrum for the channel, the number of taps in the Rake receiver, the Doppler spread, and the signal-to-noise ratio     

Weak magnetic field pattern detection by CMOS magnetic latch

A CMOS magnetic latch for digital magnetic field detection is reported. It is based on a single split-drain magnetic field-effect transistor with a positive feedback imported by a pair of lateral floating gates. The magnetic latch achieves its maximum magnetic sensitivity when latch-up takes place. A linear equation is used to model the positive feedback and the latch-up process. By imposing a reset-evaluation mechanism, the magnetic latch is evaluated for digital magnetic pattern detection. Experimental results show that the minimum detectable magnetic flux density for the magnetic latch could be down to less than 0.1 mT with low bit error rate.     

16 QAM Carrier Recovery PLL for Service-Channel Transmission Using FSK Additional Modulation

This paper describes the design and performance of the 16 QAM carrier recovery PLL for service-channel transmission using FSK additional modulation. When FSK additional modulation is applied, tracking phase error occurs and corrupts the 16 QAM signal. To reduce the phase error without widening the loop noise bandwidth is an important issue in the 16 QAM-FSK double modulation scheme. An analytical expression to estimate the peak phase error due to class 4 partial response FSK is established, By using the approximation formula, an optimization of the carrier recovery PLL is presented. Moreover, experiments and computer simulations are carried out for the 200 Mbit/s 16 QAM and 64 kbit/s SC double modulation system. As a result, it is demonstrated that a 0.1 dB 16 QAM equivalent power loss and an 8 dB frequency deviation margin of SC transmission performance can be obtained.