信号与系统 课件 英文版3

1、 6 Time and frequency characterization of S&S6.1 The Magnitude-phase Representation of the Fourier TransformFor signal x(t) :6. Time and Frequency Characterization of Signals and Systems 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S 6 Time and frequency ch

2、aracterization of S&S 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S6.2 The Magnitude-phase Representation of the Frequency Response of LTI SystemSystem characterization:Impulse response:Frequency response: 6 Time and frequency characterization of S&S6.2.1

3、Linear and Nonlinear PhaseLinear phase:Nonlinear phase:Example:Effect: Linear phase means non-distortion of signal transmission. 6 Time and frequency characterization of S&S( Linear phase )( Nonlinear phase )( Original signal ) 6 Time and frequency characterization of S&S6.2.2 Group DelayDefinition:

4、Example:Distortionless system: is flat. 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S6.2.3 Log-Magnitude and Bod PlotsMagnitude spectrum:Phase spectrum: 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S6.3 Time-Domai

5、n Properties of Ideal Frequency- selective FiltersLowpass filter:(1) Continous time:(2) Discrete time: 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S6.4 Time-Domain and Frequency-domain Aspects of Non-ideal FiltersBasic parameter of lowpass filter: 6 Time and frequency characterization of S&S 6 Time and frequency characterization of S&S 6 Time and frequency