為了在CDMA系統(tǒng)中更好地應(yīng)用QDPSK數(shù)字調(diào)制方式，在分析四相相對移相（QDPSK)信號調(diào)制解調(diào)原理的基礎(chǔ)上，設(shè)計了一種QDPSK調(diào)制解調(diào)電路，它包括串并轉(zhuǎn)換、差分編碼、四相載波產(chǎn)生和選相、相干解調(diào)、差分譯碼和并串轉(zhuǎn)換電路。在MAX+PLUSⅡ軟件平臺上，進行了編譯和波形仿真。綜合后下載到復(fù)雜可編程邏輯器件EPM7128SLC84-15中，測試結(jié)果表明，調(diào)制電路能正確選相，解調(diào)電路輸出數(shù)據(jù)與QDPSK調(diào)制輸入數(shù)據(jù)完全一致，達到了預(yù)期的設(shè)計要求。
Abstract:
In order to realize the better application of digital modulation mode QDPSK in the CDMA system， a sort of QDPSK modulation-demodulation circuit was designed based on the analysis of QDPSK signal modulation-demodulation principles. It included serial/parallel conversion circuit, differential encoding circuit, four-phase carrier wave produced and phase chosen circuit, coherent demodulation circuit, difference decoding circuit and parallel/serial conversion circuit. And it was compiled and simulated on the MAX+PLUSⅡ software platform,and downloaded into the CPLD of EPM7128SLC84-15.The test result shows that the modulation circuit can exactly choose the phase，and the output data of the demodulator circuit is the same as the input data of the QDPSK modulate. The circuit achieves the prospective requirement of the design.
為提升虛擬儀器傳輸速率與實時性能，擴展監(jiān)測范圍，在VC的軟件平臺上設(shè)計了一種全功能虛擬示波器。與傳統(tǒng)虛擬示波器相比，該系統(tǒng)采用嵌入式系統(tǒng)完成信號采集，采用工業(yè)以太網(wǎng)為傳輸介質(zhì)，通過線性插值算法和多線程編程思想，實現(xiàn)波形顯示、參數(shù)計算、頻譜分析以及波形存儲及回放功能。實驗結(jié)果表明，該虛擬示波器可以實現(xiàn)20 kHz采樣頻率下的波形精確顯示，達到預(yù)期的各項指標(biāo)。
Abstract:
o enhance the transfer rate and real-time of virtual instrument performance， expand scope of monitoring， this paper uses the VCs software platform to design a fully functional virtual oscilloscope. Compared with traditional virtual oscilloscope， this system adopts the embedded system to complete the data acquisition， industrial Ethernet as the transmission medium used by the linear interpolation algorithm and multi-threaded programming ideas， namely to achieve waveform display， parameter calculation， spectrum analysis and waveform storage and playback. Experimental results show that the virtual oscilloscope can accurately display the waveform with 20kHz sampling frequency， and achieve the desired targets.
機電類比法是一種把機械量通過一定的計算等效類比為電量的方法，其在對電子機械系統(tǒng)的分析中應(yīng)用非常廣泛。它能夠把一個較復(fù)雜的機械系統(tǒng)類比為我們熟知的電路系統(tǒng)來進行分析，從而使問題的分析得到簡化。本文通過對振弦式傳感器的分析介紹了機電類比法，并對使用電路進行了相關(guān)的分析。 Summary：The electromechanical analogy is assort of analysis which is to analogize the mechanical system by using circuit system , it applied widely in the filed of analysis the electronic-mechanical system. The analysis can take a complex mechanical system analogous to a circuitry that we well-known, which can simplify the problems. In the paper, the electro-mechanical analogy method is briefly introduced by analysis the vibrating wire sensor，and have a correlation analysis about the circuit we used.關(guān)鍵詞： 機電類比法 振弦式傳感器 頻率 振蕩 反饋Keyword：electro-mechanical analogy method，vibrating wire sensor，frequency, oscillation, feedback
0 引言振弦式傳感器是屬于頻率式傳感器的一種。所謂頻率式傳感器就是能直接將被測量轉(zhuǎn)換為振動頻率信號的傳感器，這類傳感器一般是通過測量振弦、振筒、振梁、振膜等彈性振體或石英晶體諧振器的固有諧振頻率來達到測量引起諧振頻率變化的被測非電量的目的，其也稱為諧振式傳感器[1]。在分析該類傳感器中，由于其涉及到頻率，就容易讓人聯(lián)想到在電子技術(shù)中接觸到的RLC振蕩電路。因此可以嘗試著用類比的方法使之對應(yīng)起來分析,即機電類比法分析。
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
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.
Agilent AN 154 S-Parameter Design Application Note S參數(shù)的設(shè)計與應(yīng)用
The need for new high-frequency, solid-state circuitdesign techniques has been recognized both by microwaveengineers and circuit designers. These engineersare being asked to design solid state circuitsthat will operate at higher and higher frequencies.The development of microwave transistors andAgilent Technologies’ network analysis instrumentationsystems that permit complete network characterizationin the microwave frequency rangehave greatly assisted these engineers in their work.The Agilent Microwave Division’s lab staff hasdeveloped a high frequency circuit design seminarto assist their counterparts in R&D labs throughoutthe world. This seminar has been presentedin a number of locations in the United States andEurope.From the experience gained in presenting this originalseminar, we have developed a four-part videotape, S-Parameter Design Seminar. While the technologyof high frequency circuit design is everchanging, the concepts upon which this technologyhas been built are relatively invariant.The content of the S-Parameter Design Seminar isas follows:
This application note describes how to implement the Bus LVDS (BLVDS) interface in the supported Altera ® device families for high-performance multipoint applications. This application note also shows the performance analysis of a multipoint application with the Cyclone III BLVDS example.
One of the strengths of Synplify is the Finite State Machine compiler. This is a powerfulfeature that not only has the ability to automatically detect state machines in the sourcecode, and implement them with either sequential, gray, or one-hot encoding. But alsoperform a reachability analysis to determine all the states that could possibly bereached, and optimize away all states and transition logic that can not be reached.Thus, producing a highly optimal final implementation of the state machine.
針對嵌入式機器視覺系統(tǒng)向獨立化、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。基于對智能相機體系結(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)外的幾款智能相機進行比較。綜合技術(shù)發(fā)展現(xiàn)狀，提出基于FPGA+DSP模式的硬件平臺，并提出智能相機的發(fā)展方向。分析結(jié)果表明，該系統(tǒng)設(shè)計可以實現(xiàn)脫離PC運行，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.
