精品課程大學(xué)物理-信號(hào)與系統(tǒng)(已修改)
2025-08-03 09:59 本頁(yè)面
【正文】 Signals amp。 Systems信 號(hào) 與 系 統(tǒng) CHAPTER 1 INTRODUCTION Contents ?Description amp。Classification of signals ?Operations on signals ?Description amp。Classification of systems Why Study the course —— Signals and Systems ? Purpose This subject is about using mathematical techniques to help analyze and synthesis systems which process signals. The purpose of this course is to prove a mon background for subsequent courses in control, munications, electronic circuits, filter design, and digital signal processing. What? What is a signal? What is a system? The signals , which are functions of one or more independent variables, contain information about the behavior or nature of some physical phenomena, whereas the systems respond to particular signals by producing other signals or some desired 15 The interaction between a system and its associated signals is illustrated in the following schematic diagram: System Input signal Output signal Transmit or process f(t) y(t) ? A signal is formally defined as a function of one or more independent variables that contains information about some physical phenomena. ? A system is formally defined as an entity that manipulates one or more signals to acplish a specific function. How? ?Curriculum Characteristic and Study Method ?References ?Study Arrangement Curriculum Characteristic and Study Method ： 物理概念、數(shù)學(xué)概念和工程概念并重 著重掌握信號(hào)與系統(tǒng)分析的 基本思想 和 方法 注意 問題的提出 、 分析問題 和 解決問題 的方法 :理論與實(shí)際相結(jié)合，講、練、做相結(jié)合 ? 作業(yè) ? 計(jì)算機(jī)實(shí)踐： MATLAB是信號(hào)分析與處理的強(qiáng)大工具 REFERENCES (1). Oppenheim, 劉樹棠譯， 《 信號(hào)與系統(tǒng) 》 ,西安交通大學(xué)出版社， 2022 (2)Hwei , 駱麗，胡健，李哲英譯， 《 信號(hào)與系統(tǒng) 》 ，科學(xué)出版社， 2022 (3)鄭君里等 ,《 信號(hào)與系統(tǒng) 》 ，第 2版 , 高等教育出版社， 2022 (4)胡光銳等， 《 信號(hào)與系統(tǒng)解題指南 》 ，科學(xué)出版社， 2022 (5)閔大鎰，張慶孚編， 《 信號(hào)與系統(tǒng)自學(xué)輔導(dǎo)與應(yīng)試指南 》電子科技大學(xué)出版社， 1999 Study Arrangement ? 預(yù)習(xí) +聽課 +復(fù)習(xí) ? 書面作業(yè) (按時(shí) ) ? 平時(shí) 30%+期末考試 70% 信號(hào)的描述 Description of signals 信號(hào)的概念 信號(hào)是信息（如語(yǔ)言、圖象、數(shù)據(jù)、音樂等）的載體，信息是信號(hào)的內(nèi)涵。信息的傳輸體現(xiàn)在信號(hào)變化之中，信號(hào)是任何運(yùn)動(dòng)或狀態(tài)變化的反映。 Signals are variables that carry information. Time is often the independent variable. Example: the electrical activity of the heart recorded with chest electrodes – the electrocardiogram (ECG or EKG) 0001 1010 0111 1100 0110 0101 0101 0111 0110 0101 0001 1000 語(yǔ)音信號(hào) (speech signal): 空氣壓力隨時(shí)間變化的信號(hào) f(t)。 一段語(yǔ)音信號(hào) (―對(duì)了” ) 。抽樣頻率 =22050Hz 0 0 Classification of signals and Multidimensional signal 2. Continuous Time（ CT） and discrete time（ DT） Signals (analogue signals and digital signals) 3. Periodic and Aperiodic Signals 4. Deterministic and Stochastic (nondeterministic) Signals 5. Odd and Even Signals Onedimensional and multidimensional signals ? Speech and music signals – present air pressure as a function of time at a point in space. It’s a onedimensional signal: x(t) ? Waveform of the speech signal ―light up‖and ―豆豆你好” are shown below 0 500 1000 1500 2022 2500 3000 3500 4000 450032101234s p e e c h s i g n a l x(t) Onedimensional and multidimensional signals ? Blackand white picture – Represent light intensity as a function of two spatial coordinates. ? Twodimensional signal: I(x,y) I(x,y) Lena Onedimensional and multidimensional signals ? Color picture – represent red, green and blue light intensity as a function of two spatial coordinates ???????????),(),(),(),(yxIyxIyxIyxIBGRmandrill(山魈 ) Onedimensional and multidimensional signals ? Video signals – consists of a sequence of images, called frames , and is a function of 3 variables: 2 spatial co
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