《信号与系统教学资料》chapter1.pptxVIP

Signals and SystemsSpring 2015Name: 朱凯光Cell phonemail:zhukaiguang@jlu.edu.cnOffice:Room 324, Geology PalaceAdiministrative details:Notebook for exercises not a piece of paper;No talking in the class when the teacher is talking;Quiz occasionally;No excuse necessarily for being absent;Score=60% final examination + 20% midterm examination +15% exercises+ 5% experimentsThe signals, which are functions of one or more independent variables, contain information about the behavior or nature of some phenomenon, whereas the systems respond to particular signals by producing other signals or some desired behavior. Signals and systems, Analysis, domains, Digital signal processing through the specified systems.Chapter 1 Signals and systems1. CT and DT Signals: exponential signals2. Singularity signals3. Signal decomposition and synthesis4. Systems and its properties CT and DT Signals:Electrical signals ---voltages and currents in a circuit?Video signals ---intensity variations in an image (e.g. a CAT scan)? Biological signals ---sequence of bases in a geneAcoustic signals ---audio or speech signals (analog or digital)Signals we collected from seismic surveyWeekly Dow-Jones industrial average Signals we collected from airborne electromagnetic survey?Can be continuous—An output voltage or current of an circuit, an recording of speech?Can be discrete—DNA base sequence, Digital image pixels?Can be 1-D, 2-D, ??? N-D, the number of independent variablesSignals are represented mathematically as functions of one or more independent variables.1) Signal definitionIn the case of CT Signals, the independent variables is continuous, and thus these signals are defined for a continuum of values of the independent variables.Most of the signals in the physical world are CT signals—E.g. voltage current, pressure, temperature, velocity, etc.The DT Signals are defined only at discrete times, and consequently, for these signals, the independent variable takes on only a discrete set of