The opening report mainly consists of seven parts: the background, research significance, research status at home and abroad, problems to be studied and solved, research methods to be adopted, time arrangement and references. Let's take a look at the opening report of graduation design of electronic information engineering:
1, subject source
This topic comes from laboratory construction, and the research object is matlab simulation of signal modulation and demodulation.
2. The purpose and significance of the research.
2. 1, use
I chose the topic "matlab Simulation of Signal Modulation and Demodulation" as my graduation project. Its main purpose is to further study and consolidate the communication principle and its related knowledge through this course design, learn to apply what you have learned, make yourself use what you have learned comprehensively in the design process, and be more familiar with and master the use of matlab. Have a deep understanding of the principle and realization of signal modulation and demodulation; Lay a solid foundation for entering the society and participating in the work soon; Master the ability of collecting data, digesting data and synthesizing data.
2.2, meaning
Engaged in electronic communication industry and unable to skillfully use matlab electronic circuit design software, it will be difficult to move in work and study. In mathematics, electronics, finance and other industries, the use of matlab and other computer software for product design and simulation has become a trend for a long time. The advent of such software has greatly improved the quality and efficiency of product design for designers in communications, electronics and other industries. As we all know, in the actual process, signal transmission has to go through the process of modulation and demodulation. Because the original signal from the message, that is, the modulated signal, has low spectral components, the signal is not suitable for transmission in many channels. Therefore, modulation process is usually needed at the transmitting end of communication system, and demodulation process is needed at the receiving end.
3. Research status and development trend at home and abroad.
3. 1, research status
Matlab is a kind of science and engineering calculation software introduced by math works Company in 1984. Engineers, researchers, mathematicians and educators can complete the corresponding scientific calculation work under the unified platform through matlab and related toolboxes.
Matlab itself contains more than 600 functions for mathematical calculation, statistics and engineering processing, which can quickly complete scientific calculation tasks without additional development. The industry-leading toolbox algorithm has greatly expanded the application field of matlab, so matlab has been widely concerned since it came out, and the signal processing toolbox is one of them. In the signal processing toolbox, matlab provides. Function commands for filter analysis, filter realization, fir filter realization, iir digital filter design, iir digital filter order estimation, etc.
3.2, development trend
Because the engineering problems we are facing are more and more complex, the analytical techniques we used to rely on are gradually insufficient. Using computer to analyze and solve engineering problems has become an essential tool for engineers today. Using matlab software to carry out scientific calculation can greatly speed up the progress of research and development, reduce the time and limited funds consumed in writing programs and developing algorithms, and thus achieve maximum efficiency.
4. The main contents of the research and the application value of the design results.
4. 1, the main content of the study.
1, principle of signal modulation and demodulation
As we all know, in the actual process, signal transmission has to go through the process of modulation and demodulation. Because the original signal from the message, that is, the modulated signal, has low spectral components, the signal is not suitable for transmission in many channels. Therefore, modulation process is usually needed at the transmitting end of communication system, and demodulation process is needed at the receiving end. However, the simulation and implementation in the computer are all digital. If the sampling frequency is high, the distortion caused by numbers will not be easily detected. It is very convenient to process signals by computer, which is one of the reasons why digital replaces analog.
2. Basic methods of signal modulation and demodulation
In signal modulation, high-frequency sinusoidal signals are usually used as carrier signals. A sinusoidal signal has three parameters: amplitude, frequency and phase, which can be modulated, called amplitude modulation, frequency modulation and phase modulation respectively. Pulse signals can also be used as carrier signals. Different characteristic parameters of pulse signal can be modulated, and the most commonly used one is pulse width modulation, which is called pulse width modulation. There are three basic ways of digital signal modulation: amplitude keying (ask), frequency keying (fsk) and phase keying (psk).
In signal demodulation, the process of detecting the modulated signal from the modulated signal is called demodulation or detection. The amplitude modulation is to make the amplitude of the modulation signal change with the value of the modulation signal, so the envelope shape of the amplitude modulation signal is consistent with the modulation signal. As long as the envelope of amplitude modulation signal can be detected, demodulation can be realized. This method is called envelope detection. After detection, the signal is low-pass filtered to filter out the high-frequency signal, so as to obtain the required modulation signal and realize demodulation.
3. matlab programming of signal modulation and demodulation.
Using more than 600 functions contained in matlab to carry out mathematical calculation, statistics and engineering processing, scientific calculation tasks can be completed quickly without additional development. Signals and Systems and Communication System Toolkit can easily use the matlab development language-M language to quickly realize the simulation of signal modulation and demodulation.
4. The realization process of the whole system
Firstly, the textbook file is written by matlab, and the signal is modulated by calling the corresponding function to generate various modulated waves and demodulate them. At the same time, the spectrum is analyzed, and then demodulated by simulink toolbox. By changing the parameters and observing the results, it provides a good basis for the design and improvement of the system.
4.2. matlab simulates the application value of signal modulation and demodulation.
Modulation and demodulation is one of the important problems in the application of signal processing, and the simulation design of the system is an important step and necessary guarantee in the design process. Matlab can be used to analyze and simulate the communication system conveniently, which is especially beneficial to the teaching and design of our electronic information specialty. On the other hand, it can also provide computer virtual experiments of analog signal modulation and demodulation for courses such as Fundamentals of High Frequency Electronic Technology and Signals and Systems.
5. Main stages and progress of the work
(1), 1 1 autumn semester XX years ago.
Accept the graduation design task book, learn the graduation design (thesis) requirements and related regulations.
(2) Week 12~20 in the fall semester of 2)XX.
Read the designated reference materials and documents (including 654.38 million printed symbols in foreign languages), and basically complete the tasks such as opening report and foreign language translation.
(3)XX spring semester 1 week.
Further revise and improve the opening report and foreign language translation to make it meet the requirements of graduation design (thesis) specification in content and format.
(4) The second week to the sixth week of XX spring semester.
Complete the circuit design of each unit, and protel assists the analysis.
(5) Week 6 to Week 12
Complete the circuit manufacturing and debugging.
(6) 13 weeks
Complete the graduation project and submit all the results to the tutor for approval.
(7) 14 weeks
thesis defence
6, the ultimate goal and completion time
Complete hardware design, provide protel circuit schematic diagram and pcb printed layout, and finally achieve the purpose of accurate application of software and hardware.
Completion time: week 15
7. Existing conditions
The existing protel software and the necessary equipment for making hardware can complete the research and design of this topic.
Take the exam and contribute.
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2. Organizing Committee of National Electronic Design Competition for College Students. Selected Works of the Fifth National Electronic Design Competition for College Students. Beijing: beijing institute of technology press. XX year 65438+ 10 month. first edition
3. The application of Sun Jiping 900mhz dds|pll in mine wireless communication system: Coal Science and Technology,No. 10 in XX.
4. Zhang Suwen and other high frequency electronic circuits. Beijing: Higher Education Press. 65438+April 0993. the third edition
5. Wang Zhengmou protel Circuit Design Practice Tutorial. Beijing: Electronic Industry Press. June twentieth. first edition
6. Guo Yong and other protel 99 se printed circuit board design courses. Beijing: Machinery Industry Press. June twentieth. first edition
7. Xu Zitu's electronic circuit simulation platform and tutorial. Wuhan: Huazhong University of Science and Technology Press. XX year 65438+ 10 month. first edition
8. Organizing Committee of National Electronic Design Competition for College Students. Selected Works of the 5th National Electronic Design Competition for College Students 94-99. Beijing: beijing institute of technology press. XX year 65438+ 10 month. first edition
9. Zeng Xingwen and other high-frequency electronic circuits. Beijing: Higher Education Press. XX year 65438+ 10 month. first edition
10. protel 99 se printed circuit board design course by Xiao Lingni et al. Beijing: Tsinghua University Publishing House. August of XX year. first edition
1 1. Research on the existence of variable frequency phase-locked loop.
12. Ye Peng, a digital programmable oscillator applied to fsk modulator, reported by Sichuan University of Science and Technology in XX1.
13. Development of Wang Zhongya PLL FM transmitter. Journal of Hubei University of Technology XX 0 1.
14. The frequency synthesizer system is analyzed and simulated by using matlab communication toolbox.
15. Design of Low Power Stereo Transmitter Based on fpga Wang Yantian Journal of South China University in Cao Dandan XX 0 1.
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