高精度的信號源是各種測試和實(shí)驗(yàn)過程中不可缺少的工具，在通信、雷達(dá)、測量、控制、教學(xué)等領(lǐng)域應(yīng)用十分廣泛。傳統(tǒng)的頻率合成方法設(shè)計的信號源在功能、精度、成本等方面均存在缺陷和不足，不能滿足電子技術(shù)的發(fā)展要求，直接數(shù)字合成（Direct Digital Synthesis）DDS技術(shù)可以提供高性能、高頻高精度的信號源，方便地獲得分辨率高且相位連續(xù)的信號，基于FPGA的DDS技術(shù)提供了升級方便并且成本低廉的解決方案。
本文對DDS的基本原理和輸出頻譜特性進(jìn)行理論分析，總結(jié)出雜散分布規(guī)律。同時以DDS的頻譜分析為基礎(chǔ)，給出了幾種改善雜散的方法。本文結(jié)合相關(guān)文獻(xiàn)資料采用傅立葉變換的方法對相位截斷時DDS雜散信號的頻譜特性進(jìn)行了研究，得到了雜散分布的規(guī)律性結(jié)論，并應(yīng)用在程序設(shè)計程中；DDS技術(shù)的實(shí)現(xiàn)依賴于高速、高性能的數(shù)字器件，本文將FPGA器件和DDS技術(shù)相結(jié)合，確定了FPGA器件的整體設(shè)計方案，詳細(xì)說明了各個模塊的功能和設(shè)計方法，并對其關(guān)鍵部分進(jìn)行了優(yōu)化設(shè)計，從而實(shí)現(xiàn)了波形發(fā)生器數(shù)字電路部分的功能。軟件部分采用模塊設(shè)計方法，十分方便調(diào)試。為了得到滿足設(shè)計要求的模擬波形，本文還設(shè)計了幅度調(diào)節(jié)、D/A轉(zhuǎn)換和低通濾波等外圍硬件電路。
實(shí)驗(yàn)結(jié)果表明，本文設(shè)計的基于DDS技術(shù)的多波形信號源基本能夠滿足普通學(xué)生實(shí)驗(yàn)室的要求。
Abstract: This document explains how the Cupertino (MAXREFDES5#) subsystem reference design meets the higher resolution, higher voltage,and isolation needs of industrial control and industrial automation applications. Hardware and firmware design files as well as FFTs andhistograms from lab measurements are provided.
Finite state machines are widely used in digital circuit designs. Generally, when designing a state machine using an HDL, the synthesis tools will optimize away all states that cannot be reached and generate a highly optimized circuit. Sometimes, however, the optimization is not acceptable. For example, if the circuit powers up in an invalid state, or the circuit is in an extreme working environment and a glitch sends it into an undesired state, the circuit may never get back to its normal operating condition.
Abstract: The rapid build out of today's smart grid raises a number of security questions. In this article,we review two recent well-documented security breaches and a report of a security gap. These situationsinclude a 2009 smart-meter hack in Puerto Rico; a 2012 password discovery in grid distributionequipment; and insecure storage of a private key in distribution automation equipment. For each of theseattacks, we examine the breach, the potential threat, and secure silicon methods that, as part of acomplete security strategy, can help thwart the attacks.
介紹一種基于CAN總線的牽引變電站自動化系統(tǒng)通訊規(guī)約的設(shè)計，CAN通訊規(guī)約采用標(biāo)準(zhǔn)幀，報文采用主動發(fā)送和發(fā)送查詢兩種處理形式。該設(shè)計在城市輕軌與地鐵牽引變電站中的應(yīng)用表明：可實(shí)現(xiàn)間隔層和通訊處理層的數(shù)據(jù)快速、可靠的交換，提高牽引變電站的安全性和穩(wěn)定性
。
Abstract:
This paper firstly presents a kind of design dealing with communicational protocol to the traction substation automation system based on CAN bus,and then comes up with the ideas that all frames of CAN communicational protocol should adopt the standard frame,and that messages be processed by two ways:sending initiatively and sending quiries.Subway and light rail application shows that the use of the CAN bus is possible to exchange data quickly and reliably between the layers of the middle and the communicational processing,hence to improve the safety and stability of traction substations.
為了提高環(huán)境參數(shù)采集的自動化水平，提升效率，設(shè)計了無線傳感器系統(tǒng)。本系統(tǒng)運(yùn)用了傳感器技術(shù)、通信技術(shù)和單片機(jī)技術(shù)，實(shí)現(xiàn)了對環(huán)境溫度、濕度、光照度以及可燃性氣體濃度等參數(shù)的檢測。它能夠?qū)崟r地與上位機(jī)進(jìn)行無線通信，滿足對環(huán)境參數(shù)實(shí)時監(jiān)測的要求。
Abstract:
In order to increase the degree of automation and improve the efficiency of the environment monitoring parameters，the wireless sensor system was developed.Combining with the technique of sensor,automatic monitoring，communication and single-chip microcomputer，it realized real-time monitoring environment parameters,such as temperature，humidity，illumination，concentration of com- bustible gas and so on.At the same time it can communicate with upper personal computers，satisfy the desire of real-time monitoring.
針對當(dāng)前安檢力學(xué)試驗(yàn)機(jī)所能完成的試驗(yàn)種類單一、自動化程度低等問題，提出一種以ATmega128單片機(jī)為核心控制器的安檢力學(xué)試驗(yàn)機(jī)的設(shè)計。詳細(xì)闡述了該安檢力學(xué)試驗(yàn)機(jī)各個組成部分的設(shè)計原理和方案，并且給出了各部分的軟件設(shè)計思想和操作流程。經(jīng)過大量測試試驗(yàn)表明：設(shè)計的安檢力學(xué)試驗(yàn)機(jī)可以完成多達(dá)十余種的力學(xué)安檢試驗(yàn)，完全符合相關(guān)國家標(biāo)準(zhǔn)，并且具有數(shù)據(jù)采集精度高、傳輸速度快、操作安全簡便等特點(diǎn)，實(shí)現(xiàn)了安檢設(shè)備的多功能化、數(shù)字化和自動化。
Abstract:
Currently， many mechanical security testing machines have only one function. The degree of automation of them is low. To solve those problems， a new kind of mechanical security testing machine， using ATmega128 micro-controller as its core controller， has been advanced. It describes the components of the machine. The principles and the scheme in the designing processes are presented in detail， and the software architecture and the operation processes of each part are given. After having done many testing， we have reached the following conclusions: the mechanical security testing machine presented can do over ten mechanical security tests complying with related national standards. It has high data acquisition accuracy and high transmission speed. The operation of the machine is simple and safe. In general， this machine is a multi-functional， highly automatic， digitalized security testing device.
