数字信号处理（英文版）全套PPT课件.pptx

1Chapter 1 Discrete Sequences and Systems 2Outline1.1 Discrete Sequences1.2 Signal Amplitude, Magnitude, Power1.3 Signal Processing Operational Symbols1.4 Introduction to Discrete Linear Time-Invariant Systems1.5 Discrete Linear Systems1.6 Time-Invariant Systems1.7 The Commutative Property of Linear Time-Invariant Systems1.8 The Causality Property of Linear Time-Invariant Systems1.9 The Stability Property of Linear Time-Invariant Systems1.10 Analyzing Linear Time-Invariant Systems 31.1.1 Discrete-time Signals{x(n)}: n is integer in the range -∞and +∞ : x(n) is one sampleE.g.x(-1)=-0.1564;x(0)=0;x(1)=0.1564;x(2)=0.3090;… 41.1.1 Discrete-time Signalsx(n)comes from: xa(t)=sin(2πft)Uniformed sampled as:xa(nT)=sin(2πfnT)T denotes sampling interval or period and its reciprocal is sampling frequency written as:sampling frequency 51.1.1 Discrete-time SignalsRelationship between xa(nT) and xa(t):Part and whole;Many curves connecting the two points x(nT) and x((n+1)T), but under certain conditions, xa(t) can be exclusively reconstructed based on xa(nT). 61.1.1 Discrete-time SignalsAbout Sequence:{x(n)} is a real sequence if x(n) is real for any n.{x(n)} is a complex sequence if x(n) is complex. {x(n)} = {xre(n)} + j{xim(n)}x(n) is a finite length sequence if it is defined only for a finite time interval as: N1≤n≤N2.The period of a finite length sequence is:N= N2-N1+1: N point sequence 71.1.1 Discrete-time SignalsAbout Sequence:x(n) is a infinite length sequence if it is defined for infinite time interval.(By appending with zeros or zero-padding, finite length sequence ?? infinite.)Three types of infinite length sequence, as: Right-side sequence 81.1.1 Discrete-time SignalsAbout Sequence:Left-side sequenceTwo-side sequence: -∞<n<∞Left-side sequence 99(1) Unit sample sequencediscrete-time impulseunit impulseShifted:1.1.2 Frequently Used Discrete Sequences()nd01()n-2d01 1010For any sequence could be expressed as the weighted sum of:shifted unit sample sequenc