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time-frequency

  • ESD - RF Technology and Circuits

    The phenomenon of electrostatic discharge (ESD) has been known for a long time, but recently a growing interest has been observed in ESD in radio frequency (RF) technology and ESD issues in RF applications.

    标签: Technology Circuits ESD and RF

    上传时间: 2020-06-05

    上传用户:shancjb

  • Radio Frequency Identification and Sensors

    There is an unprecedented enthusiasm for radio frequency identification (RFID) technologies today. RFID is based on the exchange of information carried by electromagnetic waves between a label, or tag, and a reader. This technology is currently in full economic expansion, which has manifested itself in widely backed research activities, some of which will be examined in this book.

    标签: Identification Frequency Sensors Radio and

    上传时间: 2020-06-08

    上传用户:shancjb

  • RFID+as+an+Infrastructure

    RFID (radio-frequency identification) is the use of a wireless non-contact system that uses radio-frequencyelectromagnetic fields to transfer datafrom a tag attached to an object, for the purposes of automatic identification and tracking [38]. The basic technologies for RFID have been around for a long time. Its root can be traced back to an espionage device designed in 1945 by Leon Theremin of the Soviet Union,whichretransmittedincidentradiowaves modulatedwith audioinformation. After decades of development, RFID systems have gain more and more attention from both the research community and the industry.

    标签: Infrastructure RFID as an

    上传时间: 2020-06-08

    上传用户:shancjb

  • RFID+Security

    Radio frequency identification (RFID) is a type of automatic identification systems which has gained popularity in recent years for being fast and reliable in keeping track of the individual objects. In RFID systems, contactless object identification is achieved using radio signals without the need for physical contact as the case with other existing identification technologies such as barcodes. Therefore, a huge number of items can be identified in a short amount of time with high reliability and low cost which makes the RFID technology very attractive for a wide range of applications such as supply chain management, e-health, monitoring humans, pets, animals, and many other objects, toll control, and electrical tagging. Furthermore, RFID technology eliminates the human error and reduces the total cost of the products.

    标签: Security RFID

    上传时间: 2020-06-08

    上传用户:shancjb

  • Control Systems

    Control Systems Engineering is an exciting and challenging field and is a multidisciplinary subject. This book is designed and organized around the concepts of control systems engineering using MATLAB, as they have been developed in the frequency and time domain for an introductory undergraduate or graduate course in control systems for engineer- ing students of all disciplines.

    标签: Control Systems

    上传时间: 2020-06-10

    上传用户:shancjb

  • Star Trek_ Deep Space Nine - A Stitch in Time

    Star Trek_ Deep Space Nine - A Stitch in Time - Andrew J. Robinson 英文版 格式 epub

    标签: Stitch Space Star Deep Nine Trek Time in

    上传时间: 2021-06-17

    上传用户:potato

  • 基于TMS320F2812 光伏并网发电模拟装置PROTEL设计原理图+PCB+软件源码+WORD论

    基于TMS320F2812 光伏并网发电模拟装置PROTEL设计原理图+PCB+软件源码+WORD论文文档,硬件采用2层板设计,PROTEL99SE 设计的工程文件,包括完整的原理图和PCB文件,可以做为你的学习设计参考。 摘要:本文实现了一个基于TMS320F2812 DSP芯片的光伏并网发电模拟装置,采用直流稳压源和滑动变阻器来模拟光伏电池。通过TMS320F2812 DSP芯片ADC模块实时采样模拟电网电压的正弦参考信号、光伏电池输出电压、负载电压电流反馈信号等。经过数据处理后,用PWM模块产生实时的SPWM 波,控制MOSFET逆变全桥输出正弦波。本文用PI控制算法实现了输出信号对给定模拟电网电压的正弦参考信号的频率和相位跟踪,用恒定电压法实现了光伏电池最大功率点跟踪(MPPT),从而达到模拟并网的效果。另外本装置还实现了光伏电池输出欠压、负载过流保护功能以及光伏电池输出欠压、过流保护自恢复功能、声光报警功能、孤岛效应的检测、保护与自恢复功能。系统测试结果表明本设计完全满定设计要求。关键词:光伏并网,MPPT,DSP  Photovoltaic Grid-connected generation simulator Zhangyuxin,Tantiancheng,Xiewuyang(College of Electrical Engineering, Chongqing University)Abstract: This paper presents a photovoltaic grid-connected generation simulator which is based on TMS320F2812 DSP, with a DC voltage source and a variable resistor to simulate the characteristic of photovoltaic cells. We use the internal AD converter to real-time sampling the referenced grid voltage signal, outputting voltage of photovoltaic, feedback outputting voltage and current signal. The PWM module generates SVPWM according to the calculation of the real-time sampling data, to control the full MOSFET inverter bridge output sine wave. We realized that the output voltage of the simulator can track the frequency and phase of the referenced grid voltage with PI regulation, and the maximum photovoltaic power tracking with constant voltage regulation, thereby achieved the purpose of grid-connected simulation. Additionally, this device has the over-voltage and over-current protection, audible and visual alarm, islanding detecting and protection, and it can recover automatically. The testing shows that our design is feasible.Keywords: Photovoltaic Grid-connected,MPPT,DSP 目录引言 11. 方案论证 11.1. 总体介绍 11.2. 光伏电池模拟装置 11.3. DC-AC逆变桥 11.4. MOSFET驱动电路方案 21.5. 逆变电路的变频控制方案 22. 理论分析与计算 22.1. SPWM产生 22.1.1. 规则采样法 22.1.2. SPWM 脉冲的计算公式 32.1.3. SPWM 脉冲计算公式中的参数计算 32.1.4. TMS320F2812 DSP控制器的事件管理单元 42.1.5. 软件设计方法 62.2. MPPT的控制方法与参数计算 72.3. 同频、同相的控制方法和参数计算 8

    标签: tms320f2812 光伏 并网发电 模拟 protel pcb

    上传时间: 2021-11-02

    上传用户:

  • python的time模块使用

    该文档为python的time模块使用简介文档,是一份很不错的参考资料,具有较高参考价值,感兴趣的可以下载看看………………

    标签: python

    上传时间: 2021-11-14

    上传用户:

  • STM32F0中Guard Time的设置

    客户使用STM32F091的USART工作于smartcard模式用于7816通讯,发现不正常。本篇LAT的内容简介了STM32F0中关于USART中Smartcard模式的Guard Time的设置。

    标签: stm32

    上传时间: 2022-02-22

    上传用户:d1997wayne

  • 直流电动机测速装置

    本系统采用电动机电枢供电回路串接采样电阻的方式来实现对小型直流有刷电动机的转速测量。该系统主要由二阶低通滤波电路,小信号放大电路、单片机测量显示电路、开关稳压电源电路等组成。同时自制电机测速装置,用高频磁环作为载体,用线圈绕制磁环,利用电磁感应原理检测电机运行时的漏磁,将变化的磁场信号转化为磁环上的感应电流。用信号处理单元电路将微弱电信号转化为脉冲信号,送由单片机检测,从而达到准确测量电机的速度的要求。In this system, the sampling resistance of armature power supply circuit is connected in series to measure the speed of small DC brush motor. The system is mainly composed of second-order low-pass filter circuit, small signal amplifier circuit, single-chip measurement and display circuit, switching regulated power supply circuit and so on. At the same time, the self-made motor speed measuring device uses high frequency magnetic ring as the carrier, coil winding magnetic ring, and electromagnetic induction principle to detect the leakage of magnetic field during the operation of the motor, which converts the changed magnetic field signal into the induced current on the magnetic ring. The weak electric signal is transformed into pulse signal by signal processing unit circuit, which is sent to single chip computer for detection, so as to meet the requirement of accurate measurement of motor speed.

    标签: 直流电动机

    上传时间: 2022-03-26

    上传用户: