AE06/AC04/AT04 SIGNALS AND SYSTEMS

 

1.         Introduction                                                                                                    3 hours

 

1.1               Continuous time and discrete time signals.

1.2               Signal energy and power.

1.3               Periodic signals, even and odd signals, exponential and sinusoidal signals.

1.4               The unit impulse and the unit step function.

1.5               Continuous time and discrete time systems.

1.6               Interconnection of systems.

1.7               Classification of systems – linear and nonlinear, memory and memoryless, causal and non-causal, stable and unstable, time-varying and time-invariant.

 

I [1]

 

2.         Linear Time-invariant Systems                                                                      3 hours

 

2.1   Convolution for Discrete Time Systems (DTS).    

2.2   Convolution for Continuous Time Systems (CTS).

2.3   Properties of Linear Time-Invariant (LTI) systems – commutative, distributive, associative.                             

2.4   Characterization of LTI systems – with and without memory, stable and unstable, causal and non-causal.

2.5   Unit step response of LTI systems.      

2.6   Causal LTI systems described by differential and difference equations.

 

I [2]

 

3.         Fourier Series Representation of Periodic Signals                                       6 hours                                   

 

3.1               Response of LTI systems to complex exponential.    

3.2               Fourier series representation of continuous time periodic signals.

3.3               Convergence conditions.

3.4               Properties of continuous time Fourier series – linearity, time shifting, time reversal, time scaling, multiplication, Parseval’s relation.

3.5               Application of Fourier series to analysis of linear systems.

3.6               Discrete time Fourier series – its finiteness and properties, in brief, leading to the Discrete Fourier Transform (DFT).

 

I [3]

 

4.         Continuous-time Fourier Transform                                                              6 hours

 

4.1  Aperiodic signals and the Continuous time Fourier Transform (CFT).

4.2  Convergence of CFT.

4.3  CFT of periodic signals.

4.4  Properties of the CFT – linearity, time shifting, conjugation and conjugate symmetry, differentiation and integration, time and frequency scaling, duality, Parseval’s relation.

4.5  CFT and convolution.

4.6  Multiplication property.

4.7  Application of CFT to LTI system analysis.

 

I [4]

 

5.         Discrete-time Fourier Transform                                                                  6 hours

 

5.1  Aperiodic signals and the Discrete Time Fourier Transform (DTFT).

5.2  Convergence of DTFT.

5.3  DTFT of periodic signals.

5.4  Properties of the DTFT – periodicity, linearity, time and frequency shifting, conjugation and conjugate symmetry, differencing and accumulation, time reversal, time expansion, differentiation in frequency, Parseval’s relation.

5.5  DTFT and convolution .

5.6  Multiplication property .

5.7  Application of DTFT to LTI system analysis.

 

I [5]

 

6.         Time and Frequency Characterization of Linear Systems                             3 hours

 

6.1    Magnitude phase representation of the frequency response of LTI systems.

6.2    Importance of linear phase.

6.3    Group delay.

6.4    Time domain properties of ideal frequency selective filters.

6.5    Time and frequency domain aspects of nonideal filters.

6.6    First and second order continuous time systems.

6.7    First and second order discrete time systems.

 

I [6]

 

7.         Sampling                                                                                                         3 hours

 

7.1        The sampling theorem.

7.2        Zero order hold.

7.3        Reconstruction of signals from its samples.

7.4        Aliasing.

7.5        Discrete time processing of continuous time signals.

 

I [7]

 

 

8.         Laplace Transform                                                                                         9 hours

 

8.1        Definition of the Laplace Transform (LT).

8.2        Region of convergence.

8.3        Poles and zeros.

8.4        Inverse LT.

8.5        Graphical evaluation of CFT from LT pole zero plot.

8.6        Properties of the LT – linearilty, time shifting, shifting in the s-domain, time scaling, conjugation, convolution, differentiation in the time domain, differentiation in the frequency domain.

8.7        Initial and final value theorems .

8.8        Standard LT pairs.

8.9        Analysis and characterization of LTI systems using the LT.

8.10    The unilateral LT – Examples, Properties, Applications.

        

I [9]

 

9.         Z-Transform                                                                                                    9 hours

 

9.1          Definition of the Z-Transform (ZT) .

9.2          Region of convergence.

9.3          Poles and zeros .

9.4          The inverse ZT .

9.5          Graphical evaluation of the DTFT from pole zero plot.

9.6          Properties of the ZT – linearity, time shifting, scaling in the z-domain, time reversal, time expansion, conjugation, convolution, differentiation in the z-domain.

9.7          Initial and final value theorems .

9.8          Standard ZT pairs.

9.9          Analysis and characterization of LTI systems using the ZT.

9.10      The unilateral ZT; Examples; Properties ; Applications.

 

I [10]

 

10.       Random Signals and Systems                                                                         12 hours

 

10.1            Basic concepts of probability and Random Variables  (RV).

10.2            Distribution and density functions.

10.3            Mean values and moments.

10.4            The Gaussian RV.

10.5            Joint probability.

10.6            Statistical independence.             

10.7            Random Processes (RP) – continuous and discrete, deterministic and non-deterministic, stationary and non-stationary, ergodic and non-ergodic.

10.8            Correlation functions – auto and cross, and their properties.

10.9             Sums of RP’s.

10.10        Spectral density and its properties.

10.11        Mean squared value from spectral density.

10.12        Spectral density and autocorrelation function (ACF).

10.13        White noise.

10.14        Cross spectral density.

10.15        Response of Linear systems to random inputs – mean and mean squared values of the output, ACF of system output, cross correlation between input and  output  spectral density at the output, cross spectral density between input and output.

 

II [9-12] OR III [4] OR IV [4, 5] OR V [5]

 


 

 Text Books

 

I.     A V Oppenheim, A S Willsky and S H Nawab, “Signals and Systems”, Third Indian 

       Reprint,  Prentice Hall, 2002.

 

II.   G R Cooper and C D McGillam, “Methods of Signal and System Analysis”, Holt,

       Rinehart and Winston, 1990.

 

III. S.Hary Kin, “Communication Systems”, 3rd Edition, John Willey, 1994.

 

IV.   R E Ziemen and W H Tranter, “Principles of Communication”, 3rd Edition, Houghton Mifflin, 1990.

 

V.     B P Lathi, “ Modern Digital and Analog Communication System”, Indian Edition by Prism Books, 1993.