The
Capacity of a MIMO channel with nt transmit antenna and nr recieve
antenna is analyzed. The power in parallel channel (after
decomposition) is distributed as water-filling algorithm
Capacity of a MIMO channel with nt transmit antenna and nr recieve antenna is analyzed. The power in parallel channel (after decomposition) is distributed as water-filling algorithm
為深入了解基于UC3854A控制的PFC變換器中的動力學(xué)特性，研究系統(tǒng)參數(shù)變化對變換器中分岔現(xiàn)象的影響，在建立Boost PFC變換器雙閉環(huán)數(shù)學(xué)模型的基礎(chǔ)上，用Matlab軟件對變換器中慢時(shí)標(biāo)分岔及混沌等不穩(wěn)定現(xiàn)象進(jìn)行了仿真。在對PFC變換器中慢時(shí)標(biāo)分岔現(xiàn)象仿真的基礎(chǔ)上，分析了系統(tǒng)參數(shù)變化對分岔點(diǎn)的影響，并進(jìn)行了仿真驗(yàn)證。仿真結(jié)果清晰地顯示了輸入整流電壓的幅值變化對系統(tǒng)分岔點(diǎn)的影響。
Abstract:
In order to better understand the dynamics characteristic of power factor correction converter based on UC3854A， and make the way that parameters change influences the bifurcation phenomena of the system clearly. The math model of the two closed loop circuits to the Boost PFC （Power Factor Correction） converter controller was built. Then， with the help of Matlab， the simulation for nonlinear phenomena such as chaos and slow-scale bifurcation in the PFC converter was made. Finally the factors that have influence to the phenomenon of bifurcation under slow-scale in PFC converter were analyzed. The simulation results clearly show the parameters change influences the bifurcation point of the system.
介紹基于ATmega8型單片機(jī)的溫度測量及加熱控制系統(tǒng)。分析系統(tǒng)的工作原理，詳盡討論系統(tǒng)的硬件電路和軟件流程。實(shí)驗(yàn)證明，該系統(tǒng)工作可靠，穩(wěn)定性高。
Abstract:
The new temperature measuring and heating control system based on ATmega8 MCU is introduced.The system’s working principles is analyzed.The design principles of hardware and software are also discussed in detail.This system has been testified and it works steady and reliably.
基于LabVIEW和單片機(jī)的空調(diào)溫度場測量系統(tǒng)的研究:室內(nèi)溫度是空調(diào)系統(tǒng)舒適性的重要指標(biāo),對其及時(shí)、準(zhǔn)確地測量顯得非常重要。介紹單片機(jī)AT89C51 和數(shù)字式、單總線型溫度傳感器DS18B20 組成矩形測量網(wǎng)絡(luò)采集空調(diào)室內(nèi)40 點(diǎn)溫度,LabVIEW作為開發(fā)平臺,二者之間通過串口實(shí)現(xiàn)數(shù)據(jù)通信,利用LabVIEW強(qiáng)大的數(shù)據(jù)處理和顯示功能對采集的空調(diào)溫度場數(shù)據(jù)進(jìn)行實(shí)時(shí)處理、分析和顯示,詳細(xì)介紹了系統(tǒng)的硬件結(jié)構(gòu)和軟件模塊的設(shè)計(jì)方案。關(guān)鍵詞:單片機(jī);DS18B20 ;LabVIEW;串行通信
Abstract : Temperature is a very important criterion of air condition system′s comfort , so it is very significant to measure it accurately and real timely. This paper int roduces a data acquisition system of measuring 40 point s temperature for air condition room based on single wire digital sensor DS18B20 and microcont roller AT89C51 which are composed of rectangle measuring meshwork. The data communication between LabVIEW and microcont roller is executed via serial port ,and the temperature field data of air condition room are processed analyzed and displayed on LabVIEW. The hardware and software modules are also given in detail.Keywords : single chip ;DS18B20 ;LabVIEW; serial communication
文章提出了一種精簡指令集8 位單片機(jī)中, 算術(shù)邏輯單元的工作原理。在此基礎(chǔ)上, 對比傳統(tǒng)PIC 方案、以及在ALU 內(nèi)部再次采用流水線作業(yè)的332 方案、44 方案, 并用Synopsys 綜合工具實(shí)現(xiàn)了它們。綜合及仿真結(jié)果表明, 根據(jù)該單片機(jī)系統(tǒng)要求, 44 方案速度最高, 比332 方案可提高43.9%, 而面積僅比最小的332 方案增加1.6%。在分析性能差異的根本原因之后, 闡明了該方案的優(yōu)越性。關(guān)鍵詞: 單片機(jī), 精簡指令集, 算術(shù)邏輯單元, 流水線
Abstract: Work principle for ALU in an 8_bit RISC Singlechip microcomputer is described. The traditional PIC scheme, 332 Pipeline scheme and 44 Pipeline scheme are compared on the base of the principle, which are implemented using Synopsys design tools. Results from synthesis and simulation shows that 44 scheme operates the fast, which is 43.9% faster and only 1.6% larger than 332 scheme. The essential reason why the performance is so different is analyzed.Then the advantage of 44 scheme is clarified.Key words: Singlechip, Microcomputer, RISC, ALU, Pipeline
針對嵌入式機(jī)器視覺系統(tǒng)向獨(dú)立化、智能化發(fā)展的要求，介紹了一種嵌入式視覺系統(tǒng)--智能相機(jī)。基于對智能相機(jī)體系結(jié)構(gòu)、組成模塊和圖像采集、傳輸和處理技術(shù)的分析，對國內(nèi)外的幾款智能相機(jī)進(jìn)行比較。綜合技術(shù)發(fā)展現(xiàn)狀，提出基于FPGA+DSP模式的硬件平臺，并提出智能相機(jī)的發(fā)展方向。分析結(jié)果表明，該系統(tǒng)設(shè)計(jì)可以實(shí)現(xiàn)脫離PC運(yùn)行，完成圖像獲取與分析，并作出相應(yīng)輸出。
Abstract:
This paper introduced an embedded vision system-intelligent camera ，which was for embedded machine vision systems to an independent and intelligent development requirements. Intelligent camera architecture， component modules and image acquisition， transmission and processing technology were analyzed. After comparing integrated technology development of several intelligent cameras at home and abroad， the paper proposed the hardware platform based on FPGA+DSP models and made clear direction of development of intelligent cameras. On the analysis of the design， the results indicate that the system can run from the PC independently to complete the image acquisition and analysis and give a corresponding output.
同步技術(shù)是跳頻通信系統(tǒng)的關(guān)鍵技術(shù)之一，尤其是在快速跳頻通信系統(tǒng)中，常規(guī)跳頻通信通過同步字頭攜帶相關(guān)碼的方法來實(shí)現(xiàn)同步，但對于快跳頻來說，由于是一跳或者多跳傳輸一個(gè)調(diào)制符號，難以攜帶相關(guān)碼。對此引入雙跳頻圖案方法，提出了一種適用于快速跳頻通信系統(tǒng)的同步方案。采用短碼攜帶同步信息，克服了快速跳頻難以攜帶相關(guān)碼的困難。分析了同步性能，仿真結(jié)果表明該方案同步時(shí)間短、虛警概率低、捕獲概率高，同步性能可靠。
Abstract:
Synchronization is one of the key techniques to frequency-hopping communication system， especially in the fast frequency hopping communication system. In conventional frequency hopping communication systems， synchronization can be achieved by synchronization-head which can be used to carry the synchronization information， but for the fast frequency hopping， Because modulation symbol is transmitted by per hop or multi-hop， it is difficult to carry the correlation code. For the limitation of fast frequency hopping in carrying correlation code， a fast frequency-hopping synchronization scheme with two hopping patterns is proposed. The synchronization information is carried by short code， which overcomes the difficulty of correlation code transmission in fast frequency-hopping. The performance of the scheme is analyzed， and simulation results show that the scheme has the advantages of shorter synchronization time， lower probability of false alarm， higher probability of capture and more reliable of synchronization.
Single-Ended and Differential S-Parameters
Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.
