This document provides an overview of discrete-time signals and systems in signal processing. It begins with an introduction to discrete-time signals as sequences and sampling of continuous-time signals. Common basic discrete-time sequences like impulses, steps, and exponentials are described. Properties of linear, time-invariant discrete-time systems are introduced. The frequency domain representation of discrete-time signals using complex exponentials is also covered. Examples of periodic and non-periodic discrete-time sequences are provided to illustrate key concepts.
This document provides an overview of discrete-time signals and systems in digital signal processing (DSP). It discusses key concepts such as:
1) Discrete-time signals which are represented by sequences of numbers and how common signals like impulses and steps are represented.
2) Discrete-time systems which take a discrete-time signal as input and produce an output signal through a mathematical algorithm, with the impulse response characterizing the system.
3) Important properties of linear time-invariant (LTI) systems including superposition, time-shifting of inputs and outputs, and representation using convolution sums or difference equations.
DSP_2018_FOEHU - Lec 03 - Discrete-Time Signals and SystemsAmr E. Mohamed
The document discusses discrete-time signals and systems. It defines discrete-time signals as sequences represented by x[n] and discusses important sequences like the unit sample, unit step, and periodic sequences. It then defines discrete-time systems as devices that take a discrete-time signal x(n) as input and produce another discrete-time signal y(n) as output. The document classifies systems as static vs. dynamic, time-invariant vs. time-varying, linear vs. nonlinear, and causal vs. noncausal. It provides examples to illustrate each classification.
This document summarizes key aspects of the discrete Fourier transform (DFT). It defines the DFT, provides the formula for calculating it, and explains that the DFT transforms a discrete-time signal from the time domain to the frequency domain. It also outlines several important properties of the DFT, including linearity, shift property, duality, symmetry, and circular convolution. Examples are provided to illustrate duality and symmetry. References for further information on the discrete Fourier transform are also included.
COntents:
Signals & Systems, Classification of Continuous and Discrete Time signals, Standard Continuous and Discrete Time Signals
Block Diagram Representation of System, Properties of System
Linear Time Invariant Systems (LTI)
Convolution, Properties of Convolution, Performing Convolution
Differential and Difference Equation Representation of LTI Systems
Fourier Series, Dirichlit Condition, Determination of Fourier Coefficeints, Wave Symmetry, Exponential Form of Fourier Series
Fourier Transform, Discrete Time Fourier Transform
Laplace Transform, Inverse Laplace Transform, Properties of Laplace Transform
Z-Transform, Properties of Z-Transform, Inverse Z- Transform
Text Book
Signal & Systems (2nd Edition) By A. V. Oppenheim, A. S. Willsky & S. H. Nawa
Signal & Systems
By Prentice Hall
Reference Book
Signal & Systems (2nd Edition)
By S. Haykin & B.V. Veen
Signals & Systems
By Smarajit Gosh
Digital signal processing involves processing digital signals using digital computers and software. There are several types of signals that can be classified based on properties like being continuous or discrete in time and value, deterministic or random, and single or multichannel. Common signals include unit impulse, unit step, and periodic sinusoidal waves. Signals can also be categorized as energy signals with finite energy, power signals with finite power, and even/odd based on their symmetry. Digital signal processing is used in applications like speech processing, image processing, and more.
This document discusses different types of signals including continuous and discrete time signals, periodic and aperiodic signals, even and odd signals, deterministic and random signals, and energy and power signals. It provides examples like speech, ECG, atmospheric pressure and temperature signals. Formulas for periodicity and sampling of continuous to discrete time signals are also included.
This document provides an overview of the ME 433 - State Space Control course. It introduces the course topics which include state-space modeling, observability and controllability, linear state feedback control, linear quadratic regulator, and Kalman filtering. It also lists relevant textbooks and describes various types of control problems including nonlinear, robust, adaptive, and distributed parameter systems control.
This document contains the solutions to an homework assignment on linear and nonlinear systems. It examines several examples and determines whether they are linear or nonlinear by applying the superposition principle. It also identifies examples as causal or non-causal. Finally, it analyzes some circuit examples and determines properties like memoryless, causal, linear, and time-invariant.
This document provides an overview of discrete-time signals and systems in digital signal processing (DSP). It discusses key concepts such as:
1) Discrete-time signals which are represented by sequences of numbers and how common signals like impulses and steps are represented.
2) Discrete-time systems which take a discrete-time signal as input and produce an output signal through a mathematical algorithm, with the impulse response characterizing the system.
3) Important properties of linear time-invariant (LTI) systems including superposition, time-shifting of inputs and outputs, and representation using convolution sums or difference equations.
DSP_2018_FOEHU - Lec 03 - Discrete-Time Signals and SystemsAmr E. Mohamed
The document discusses discrete-time signals and systems. It defines discrete-time signals as sequences represented by x[n] and discusses important sequences like the unit sample, unit step, and periodic sequences. It then defines discrete-time systems as devices that take a discrete-time signal x(n) as input and produce another discrete-time signal y(n) as output. The document classifies systems as static vs. dynamic, time-invariant vs. time-varying, linear vs. nonlinear, and causal vs. noncausal. It provides examples to illustrate each classification.
This document summarizes key aspects of the discrete Fourier transform (DFT). It defines the DFT, provides the formula for calculating it, and explains that the DFT transforms a discrete-time signal from the time domain to the frequency domain. It also outlines several important properties of the DFT, including linearity, shift property, duality, symmetry, and circular convolution. Examples are provided to illustrate duality and symmetry. References for further information on the discrete Fourier transform are also included.
COntents:
Signals & Systems, Classification of Continuous and Discrete Time signals, Standard Continuous and Discrete Time Signals
Block Diagram Representation of System, Properties of System
Linear Time Invariant Systems (LTI)
Convolution, Properties of Convolution, Performing Convolution
Differential and Difference Equation Representation of LTI Systems
Fourier Series, Dirichlit Condition, Determination of Fourier Coefficeints, Wave Symmetry, Exponential Form of Fourier Series
Fourier Transform, Discrete Time Fourier Transform
Laplace Transform, Inverse Laplace Transform, Properties of Laplace Transform
Z-Transform, Properties of Z-Transform, Inverse Z- Transform
Text Book
Signal & Systems (2nd Edition) By A. V. Oppenheim, A. S. Willsky & S. H. Nawa
Signal & Systems
By Prentice Hall
Reference Book
Signal & Systems (2nd Edition)
By S. Haykin & B.V. Veen
Signals & Systems
By Smarajit Gosh
Digital signal processing involves processing digital signals using digital computers and software. There are several types of signals that can be classified based on properties like being continuous or discrete in time and value, deterministic or random, and single or multichannel. Common signals include unit impulse, unit step, and periodic sinusoidal waves. Signals can also be categorized as energy signals with finite energy, power signals with finite power, and even/odd based on their symmetry. Digital signal processing is used in applications like speech processing, image processing, and more.
This document discusses different types of signals including continuous and discrete time signals, periodic and aperiodic signals, even and odd signals, deterministic and random signals, and energy and power signals. It provides examples like speech, ECG, atmospheric pressure and temperature signals. Formulas for periodicity and sampling of continuous to discrete time signals are also included.
This document provides an overview of the ME 433 - State Space Control course. It introduces the course topics which include state-space modeling, observability and controllability, linear state feedback control, linear quadratic regulator, and Kalman filtering. It also lists relevant textbooks and describes various types of control problems including nonlinear, robust, adaptive, and distributed parameter systems control.
This document contains the solutions to an homework assignment on linear and nonlinear systems. It examines several examples and determines whether they are linear or nonlinear by applying the superposition principle. It also identifies examples as causal or non-causal. Finally, it analyzes some circuit examples and determines properties like memoryless, causal, linear, and time-invariant.
Classification of signals and systems as well as their properties are given in the PPT .Examples related to types of signals and systems are also given .
DSP_FOEHU - MATLAB 01 - Discrete Time Signals and SystemsAmr E. Mohamed
This document provides an overview of discrete-time signals and systems in MATLAB. It defines discrete signals as sequences represented by x(n) and how they can be implemented as vectors in MATLAB. It describes various types of sequences like unit sample, unit step, exponential, sinusoidal, and random. It also covers operations on sequences like addition, multiplication, scaling, shifting, folding, and correlations. Discrete time systems are defined as operators that transform an input sequence x(n) to an output sequence y(n). Key properties discussed are linearity, time-invariance, stability, causality, and the use of convolution to represent the output of a linear time-invariant system. Examples are provided to demonstrate various concepts.
Digital Signal Processing[ECEG-3171]-Ch1_L03Rediet Moges
This Digital Signal Processing Lecture material is the property of the author (Rediet M.) . It is not for publication,nor is it to be sold or reproduced.
#Africa#Ethiopia
The document discusses the Discrete Fourier Transform (DFT). It begins by explaining the limitations of the Discrete Time Fourier Transform (DTFT) and Discrete Fourier Series (DFS) from a numerical computation perspective. It then introduces the DFT as a numerically computable transform obtained by sampling the DTFT in the frequency domain. The DFT represents a periodic discrete-time signal using a sum of complex exponentials. It defines the DFT and inverse DFT equations. The document also discusses properties of the DFT such as linearity and time/frequency shifting. Finally, it notes that the Fast Fourier Transform (FFT) implements the DFT more efficiently by constraining the number of points to powers of two.
Unit 1 -Introduction to signals and standard signalsDr.SHANTHI K.G
1) The document introduces various types of signals including continuous time signals, discrete time signals, standard signals like step signals, ramp signals, impulse signals, sinusoidal signals, and exponential signals.
2) Continuous time signals are defined for every instant in time while discrete time signals are defined for discrete instants in time. Common standard signals include unit step, ramp, parabolic, pulse, sinusoidal, and exponential signals.
3) Examples of applications of the standard signals are mentioned such as step signals being used for switching devices on and off, and sinusoidal signals being used to represent any sound signal.
This document discusses frequency domain representation of periodic signals. It defines spectrum as the measurable range of a physical property like frequency or wavelength. A signal's frequency domain representation plots amplitude and phase versus frequency, rather than versus time as in the time domain. The frequency domain reveals the frequencies and proportions of frequency components that make up the signal's shape. It can be obtained from the signal's Fourier series or Fourier transform. Sinusoids in continuous and discrete time are used as examples to demonstrate how their frequency domain representations graph amplitude versus frequency and phase versus frequency.
This document contains lecture notes on signals and systems for a course at Chadalawada Ramanamma Engineering College. It includes:
1. An introduction to signals, systems, and some common elementary signals like the unit step, unit impulse, ramp, sinusoid, and exponential signals.
2. A classification of signals as continuous/discrete, deterministic/non-deterministic, even/odd, periodic/aperiodic, energy/power, and real/imaginary.
3. A discussion of basic operations on signals like amplitude scaling, addition, and subtraction.
The document provides information about a signals and systems course taught by Mr. Koay Fong Thai. It includes announcements about course policies, assessments, and schedule. Students are advised to ask questions, work hard, and submit assignments on time. The use of phones and laptops in class is strictly prohibited. The course aims to introduce signals and systems analysis using various transforms. Topics include signals in the time domain, Fourier transforms, Laplace transforms, and z-transforms. Reference books and a lecture schedule are also provided.
1. The document presents the procedure for converting one type of flip-flop to another including SR to D, SR to JK, SR to T, JK to T, JK to D, JK to SR, D to T, D to SR, and T to D.
2. The procedure involves drawing the truth table for the target flip-flop, excitation table for the available flip-flop, and using a K-map to simplify the logic.
3. Examples of conversions include SR to D, SR to JK, JK to T, and D to T with accompanying truth tables, K-maps, and logic diagrams.
This document provides an introduction to wavelet transforms. It begins with an outline of topics to be covered, including an overview of wavelet transforms, the limitations of Fourier transforms, the historical development of wavelets, the principle of wavelet transforms, examples of applications, and references. It then discusses the stationarity of signals and how Fourier transforms cannot show when frequency components occur over time. Short-time Fourier analysis is introduced as a solution, but it is noted that wavelet transforms provide a more flexible approach by allowing the window size to vary. The document proceeds to define what a wavelet is, discuss the historical development of wavelet theory, provide examples of popular mother wavelets, and explain the steps to compute a continuous wave
This document discusses discrete-time signals and sequences. It defines discrete-time signals as sequences of numbers represented as x[n], where n is an integer. In practice, sequences arise from periodically sampling an analog signal. Linear time-invariant (LTI) systems are described by the convolution sum, where the impulse response h[n] completely characterizes the system. FIR systems have impulse responses of finite duration, while IIR systems can have impulse responses that extend to infinity.
1. The document discusses various operations that can be performed on signals including time reversal, time shifting, time scaling, amplitude scaling, signal addition, and signal multiplication.
2. Examples are provided to demonstrate how to graphically represent signals and how the different operations change the signals.
3. Key steps are outlined for performing each operation including reversing the time axis, delaying or advancing signals, compressing or expanding the time axis, amplifying or attenuating signal amplitude, adding or multiplying signal values.
This document discusses linear time-invariant (LTI) systems in discrete time. It introduces the convolution sum representation of LTI systems, where the output of an LTI system with impulse response h[n] and input x[n] is given by y[n]=x[n]*h[n]=∑k x[k]h[n-k]. Several examples are worked through to demonstrate calculating the output of an LTI system given its impulse response and input. The document also discusses representing discrete time signals as the sum of shifted unit impulse functions and properties of LTI systems like time-invariance.
The document discusses the design of IIR digital filters using different methods. It begins by describing the difference equation and transfer function of IIR filters. It then covers the Impulse Invariant Method and Bilinear Z-Transform (BZT) Method for designing IIR filters by transforming analog prototypes. Key steps include prewarping frequencies, designing analog filters, and applying the bilinear transform. Examples demonstrate applying these methods to design Butterworth filters.
This document discusses various operations that can be performed on signals. It was prepared by Dishant Patel, Vishal Gohel, Jay Panchal, and Manthan Panchal, and guided by Prof. Hardik Patel. The key operations discussed are time shifting, time scaling, time inversion/folding, amplitude scaling, addition, subtraction, and multiplication of signals. These basic operations are important for analyzing and manipulating signals for different purposes.
1) Microwave imaging uses electromagnetic waves in the microwave frequency range (300 MHz to 300 GHz) to evaluate hidden or embedded objects within a structure by reconstructing the distribution of electromagnetic properties like permittivity and conductivity from scattered field data.
2) The inverse problem aims to reconstruct the contrast function χ(r), which represents the difference in electromagnetic properties from a homogeneous background, based on the relationship between the measured scattered fields and χ(r).
3) The total field is calculated using Maxwell's equations and represented as the incident field, determined by the source current and Green's function, plus an additional term accounting for scattering from the contrast χ(r) integrated over the domain.
This document discusses various operations that can be performed on signals, including time shifting, time reversal, time scaling, signal addition, and signal multiplication. It provides examples and explanations of each operation. Time shifting involves shifting a signal along the time axis. Time reversal involves reversing a signal along the time axis. Time scaling involves compressing or expanding a signal along the time axis. Signal addition and multiplication involve combining two signals by adding or multiplying their corresponding sample values.
Digital signal Processing all matlab code with Lab report Alamgir Hossain
Digital signal processing(DSP) laboratory with matlab software....
Problem List :
1.To write a Matlab program to evaluate the impulse response of the system.
2.Computation of N point DFT of a given sequence and to plot magnitude and phase spectrum.
3.To Generate continuous time sinusoidal signal, discrete time cosine signal.
4.To find the DFT / IDFT of given signal.
5.Program for generation of Sine sequence.
6.Program for generation of Cosine sequence.
7. Program for the generation of UNIT impulse signal
8. Program for the generation of Exponential signal.
DSP Applications in medical field:Hearing aid, ECG, Blood pressure monitor.
Noise filtering,Fast fourier transform and Bandpass & FIR filter on matlab.
This document provides an introduction to discrete-time signals and systems. It defines basic concepts such as discrete-time signals and sequences, basic sequence operations, and common signal types including unit sample, unit step, and periodic sequences. It also introduces discrete-time systems as transformations that map an input sequence to an output sequence. Properties of systems such as linearity, time-invariance, causality, stability, and properties of linear time-invariant (LTI) systems including impulse response and convolution are discussed. The document concludes with examples and end of chapter problems.
1) Discrete-time signals are functions of independent integer variables where samples are only defined at discrete time instants. 2) A discrete-time system transforms an input signal into an output signal through operations like addition, multiplication, delay. 3) Linear, time-invariant (LTI) systems have properties of superposition and time-invariance, and their behavior can be characterized by the impulse response. The output of an LTI system is the convolution of the input and impulse response.
Classification of signals and systems as well as their properties are given in the PPT .Examples related to types of signals and systems are also given .
DSP_FOEHU - MATLAB 01 - Discrete Time Signals and SystemsAmr E. Mohamed
This document provides an overview of discrete-time signals and systems in MATLAB. It defines discrete signals as sequences represented by x(n) and how they can be implemented as vectors in MATLAB. It describes various types of sequences like unit sample, unit step, exponential, sinusoidal, and random. It also covers operations on sequences like addition, multiplication, scaling, shifting, folding, and correlations. Discrete time systems are defined as operators that transform an input sequence x(n) to an output sequence y(n). Key properties discussed are linearity, time-invariance, stability, causality, and the use of convolution to represent the output of a linear time-invariant system. Examples are provided to demonstrate various concepts.
Digital Signal Processing[ECEG-3171]-Ch1_L03Rediet Moges
This Digital Signal Processing Lecture material is the property of the author (Rediet M.) . It is not for publication,nor is it to be sold or reproduced.
#Africa#Ethiopia
The document discusses the Discrete Fourier Transform (DFT). It begins by explaining the limitations of the Discrete Time Fourier Transform (DTFT) and Discrete Fourier Series (DFS) from a numerical computation perspective. It then introduces the DFT as a numerically computable transform obtained by sampling the DTFT in the frequency domain. The DFT represents a periodic discrete-time signal using a sum of complex exponentials. It defines the DFT and inverse DFT equations. The document also discusses properties of the DFT such as linearity and time/frequency shifting. Finally, it notes that the Fast Fourier Transform (FFT) implements the DFT more efficiently by constraining the number of points to powers of two.
Unit 1 -Introduction to signals and standard signalsDr.SHANTHI K.G
1) The document introduces various types of signals including continuous time signals, discrete time signals, standard signals like step signals, ramp signals, impulse signals, sinusoidal signals, and exponential signals.
2) Continuous time signals are defined for every instant in time while discrete time signals are defined for discrete instants in time. Common standard signals include unit step, ramp, parabolic, pulse, sinusoidal, and exponential signals.
3) Examples of applications of the standard signals are mentioned such as step signals being used for switching devices on and off, and sinusoidal signals being used to represent any sound signal.
This document discusses frequency domain representation of periodic signals. It defines spectrum as the measurable range of a physical property like frequency or wavelength. A signal's frequency domain representation plots amplitude and phase versus frequency, rather than versus time as in the time domain. The frequency domain reveals the frequencies and proportions of frequency components that make up the signal's shape. It can be obtained from the signal's Fourier series or Fourier transform. Sinusoids in continuous and discrete time are used as examples to demonstrate how their frequency domain representations graph amplitude versus frequency and phase versus frequency.
This document contains lecture notes on signals and systems for a course at Chadalawada Ramanamma Engineering College. It includes:
1. An introduction to signals, systems, and some common elementary signals like the unit step, unit impulse, ramp, sinusoid, and exponential signals.
2. A classification of signals as continuous/discrete, deterministic/non-deterministic, even/odd, periodic/aperiodic, energy/power, and real/imaginary.
3. A discussion of basic operations on signals like amplitude scaling, addition, and subtraction.
The document provides information about a signals and systems course taught by Mr. Koay Fong Thai. It includes announcements about course policies, assessments, and schedule. Students are advised to ask questions, work hard, and submit assignments on time. The use of phones and laptops in class is strictly prohibited. The course aims to introduce signals and systems analysis using various transforms. Topics include signals in the time domain, Fourier transforms, Laplace transforms, and z-transforms. Reference books and a lecture schedule are also provided.
1. The document presents the procedure for converting one type of flip-flop to another including SR to D, SR to JK, SR to T, JK to T, JK to D, JK to SR, D to T, D to SR, and T to D.
2. The procedure involves drawing the truth table for the target flip-flop, excitation table for the available flip-flop, and using a K-map to simplify the logic.
3. Examples of conversions include SR to D, SR to JK, JK to T, and D to T with accompanying truth tables, K-maps, and logic diagrams.
This document provides an introduction to wavelet transforms. It begins with an outline of topics to be covered, including an overview of wavelet transforms, the limitations of Fourier transforms, the historical development of wavelets, the principle of wavelet transforms, examples of applications, and references. It then discusses the stationarity of signals and how Fourier transforms cannot show when frequency components occur over time. Short-time Fourier analysis is introduced as a solution, but it is noted that wavelet transforms provide a more flexible approach by allowing the window size to vary. The document proceeds to define what a wavelet is, discuss the historical development of wavelet theory, provide examples of popular mother wavelets, and explain the steps to compute a continuous wave
This document discusses discrete-time signals and sequences. It defines discrete-time signals as sequences of numbers represented as x[n], where n is an integer. In practice, sequences arise from periodically sampling an analog signal. Linear time-invariant (LTI) systems are described by the convolution sum, where the impulse response h[n] completely characterizes the system. FIR systems have impulse responses of finite duration, while IIR systems can have impulse responses that extend to infinity.
1. The document discusses various operations that can be performed on signals including time reversal, time shifting, time scaling, amplitude scaling, signal addition, and signal multiplication.
2. Examples are provided to demonstrate how to graphically represent signals and how the different operations change the signals.
3. Key steps are outlined for performing each operation including reversing the time axis, delaying or advancing signals, compressing or expanding the time axis, amplifying or attenuating signal amplitude, adding or multiplying signal values.
This document discusses linear time-invariant (LTI) systems in discrete time. It introduces the convolution sum representation of LTI systems, where the output of an LTI system with impulse response h[n] and input x[n] is given by y[n]=x[n]*h[n]=∑k x[k]h[n-k]. Several examples are worked through to demonstrate calculating the output of an LTI system given its impulse response and input. The document also discusses representing discrete time signals as the sum of shifted unit impulse functions and properties of LTI systems like time-invariance.
The document discusses the design of IIR digital filters using different methods. It begins by describing the difference equation and transfer function of IIR filters. It then covers the Impulse Invariant Method and Bilinear Z-Transform (BZT) Method for designing IIR filters by transforming analog prototypes. Key steps include prewarping frequencies, designing analog filters, and applying the bilinear transform. Examples demonstrate applying these methods to design Butterworth filters.
This document discusses various operations that can be performed on signals. It was prepared by Dishant Patel, Vishal Gohel, Jay Panchal, and Manthan Panchal, and guided by Prof. Hardik Patel. The key operations discussed are time shifting, time scaling, time inversion/folding, amplitude scaling, addition, subtraction, and multiplication of signals. These basic operations are important for analyzing and manipulating signals for different purposes.
1) Microwave imaging uses electromagnetic waves in the microwave frequency range (300 MHz to 300 GHz) to evaluate hidden or embedded objects within a structure by reconstructing the distribution of electromagnetic properties like permittivity and conductivity from scattered field data.
2) The inverse problem aims to reconstruct the contrast function χ(r), which represents the difference in electromagnetic properties from a homogeneous background, based on the relationship between the measured scattered fields and χ(r).
3) The total field is calculated using Maxwell's equations and represented as the incident field, determined by the source current and Green's function, plus an additional term accounting for scattering from the contrast χ(r) integrated over the domain.
This document discusses various operations that can be performed on signals, including time shifting, time reversal, time scaling, signal addition, and signal multiplication. It provides examples and explanations of each operation. Time shifting involves shifting a signal along the time axis. Time reversal involves reversing a signal along the time axis. Time scaling involves compressing or expanding a signal along the time axis. Signal addition and multiplication involve combining two signals by adding or multiplying their corresponding sample values.
Digital signal Processing all matlab code with Lab report Alamgir Hossain
Digital signal processing(DSP) laboratory with matlab software....
Problem List :
1.To write a Matlab program to evaluate the impulse response of the system.
2.Computation of N point DFT of a given sequence and to plot magnitude and phase spectrum.
3.To Generate continuous time sinusoidal signal, discrete time cosine signal.
4.To find the DFT / IDFT of given signal.
5.Program for generation of Sine sequence.
6.Program for generation of Cosine sequence.
7. Program for the generation of UNIT impulse signal
8. Program for the generation of Exponential signal.
DSP Applications in medical field:Hearing aid, ECG, Blood pressure monitor.
Noise filtering,Fast fourier transform and Bandpass & FIR filter on matlab.
This document provides an introduction to discrete-time signals and systems. It defines basic concepts such as discrete-time signals and sequences, basic sequence operations, and common signal types including unit sample, unit step, and periodic sequences. It also introduces discrete-time systems as transformations that map an input sequence to an output sequence. Properties of systems such as linearity, time-invariance, causality, stability, and properties of linear time-invariant (LTI) systems including impulse response and convolution are discussed. The document concludes with examples and end of chapter problems.
1) Discrete-time signals are functions of independent integer variables where samples are only defined at discrete time instants. 2) A discrete-time system transforms an input signal into an output signal through operations like addition, multiplication, delay. 3) Linear, time-invariant (LTI) systems have properties of superposition and time-invariance, and their behavior can be characterized by the impulse response. The output of an LTI system is the convolution of the input and impulse response.
Ch2_Discrete time signal and systems.pdfshannlevia123
This document discusses topics related to discrete-time signals and systems from the textbook Discrete-Time Signal Processing by Alan V. Oppenheim and Ronald W. Schafer. It covers sampling of continuous-time signals to obtain discrete-time signals, basic discrete-time sequences and operations, discrete-time systems including linear and time-invariant systems, and examples such as the ideal delay system and moving average filter. Frequency characteristics of discrete-time signals such as periodicity are also examined.
The document summarizes key concepts about linear time-invariant (LTI) systems from Chapter 2. It discusses:
1) LTI systems can be modeled as the sum of their impulse responses weighted by the input signal. This is known as the convolution sum/integral for discrete/continuous-time systems.
2) Any signal can be represented as a linear combination of shifted unit impulses. The output of an LTI system is the convolution of the input signal with the system's impulse response.
3) The impulse response completely characterizes an LTI system. The output is found by taking the convolution integral or sum of the input signal with the impulse response.
This document provides an introduction to discrete-time signals and linear time-invariant (LTI) systems. It defines discrete-time signals as sequences represented at discrete time instants. Basic discrete-time sequences including the unit sample, unit step, and periodic sequences are described. Discrete-time systems are defined as transformations that map an input sequence to an output sequence. Linear and time-invariant systems are introduced. For LTI systems, the impulse response is defined and convolution is used to represent the output as a summation of the input multiplied by delayed versions of the impulse response. Key properties of LTI systems including superposition, scaling, time-invariance, and the commutative property of convolution are covered.
1. The document discusses signals and systems, including continuous-time and discrete-time signals. It covers topics like transformations of signals, exponential and sinusoidal signals, and basic properties of systems.
2. Continuous-time signals are represented as functions of time t, while discrete-time signals are represented as sequences indexed by integer n. Exponential and sinusoidal signals can be represented using complex exponential functions.
3. The document provides examples and formulas for calculating energy, power, and other properties of signals. It also describes how signals can be transformed through operations like time shifting, scaling, reversal, and periodicity.
1. The document summarizes a lecture on discrete-time signals and systems.
2. It defines different types of signals, including discrete-time and discrete-valued signals which are relevant for digital filter theory.
3. It also classifies systems as static vs. dynamic, time-invariant vs. time-variable, linear vs. nonlinear, causal vs. non-causal, stable vs. unstable, and recursive vs. non-recursive.
4. It describes the time-domain representation of linear, time-invariant (LTI) systems using impulse response and convolution.
This document outlines the syllabus and course objectives for the digital signal processing course ECE2006 being offered in the fall semester of 2021. The course aims to teach students concepts related to signals and systems in the time and frequency domains, design of analog and digital filters, and realization of digital filters using various structures. The syllabus is divided into 7 modules covering topics such as Fourier analysis, design of IIR and FIR filters, and realization of lattice filters. Students will be evaluated through continuous assessments, quizzes, assignments, and a final exam.
This document summarizes key concepts in digital signal processing systems. It defines a system as a combination of elements that processes an input signal to produce an output signal. Systems are classified as continuous or discrete time, lumped or distributed parameter, static or dynamic, causal or non-causal, linear or non-linear, time variant or invariant, and stable or unstable. Convolution and the discrete Fourier transform (DFT) are also introduced as important tools in digital signal processing. The DFT transforms a signal from the time domain to the frequency domain.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
This document summarizes research on using an affine combination of two time-varying least mean square (TVLMS) adaptive filters for applications such as echo cancellation and system identification. The affine combination aims to obtain faster convergence and lower steady-state error compared to individual TVLMS filters. Simulation results show the affine combination of TVLMS filters achieves mean square error of 0.0055 after 1000 iterations for noise cancellation, outperforming standard LMS, affine LMS, and RLS algorithms. The affine combination also performs well for system identification applications, identifying an unknown FIR filter model with low error. The approach provides dependent estimates of an unknown system response from each filter, and finds an optimal affine combining coefficient to minimize mean square error
1. The document discusses different types of systems based on their properties, including static vs dynamic, time-variant vs time-invariant, linear vs non-linear, causal vs non-causal, and stable vs unstable.
2. A system is defined as a physical device or algorithm that performs operations on a discrete-time signal. Static systems have outputs that depend only on the present input, while dynamic systems have outputs that depend on present and past/future inputs.
3. Time-invariant systems have characteristics that do not change over time, while time-variant systems have characteristics that do change. Linear systems follow the superposition principle, while causal systems have outputs dependent only on present and past inputs.
The document discusses linear time-invariant (LTI) systems. It explains that:
1) The response of an LTI system to any input can be found by convolving the system's impulse response with the input. This is done using a convolution sum in discrete time and a convolution integral in continuous time.
2) Discrete-time signals and continuous-time signals can both be represented as weighted sums or integrals of shifted impulse functions.
3) For LTI systems, the impulse responses are simply time-shifted versions of the same underlying function, allowing the system to be fully characterized by its impulse response.
This document provides an overview of digital signal processing systems. It defines a system as a physical device or algorithm that performs operations on a discrete time signal. A system has an input signal x(n), performs a process, and produces an output signal y(n). Systems can be classified based on their properties as static/dynamic, time-invariant/time-variant, linear/non-linear, causal/non-causal, and stable/unstable. Examples of each system type are provided. The key aspects covered are the definitions of each system property, how to determine if a given system has a particular property, and examples to illustrate the concepts.
This document describes work on developing spectrum-based regularization approaches for linear inverse problems. The author proposes using a learned distribution of singular values to build regularization models that are better suited for recovering signals correlated with medium frequencies, not just low frequencies as in traditional models. Algorithms are presented for learning the singular value profile from training data and for solving the resulting regularization models. Experimental results demonstrate that the proposed spectrum-learning regularization and SLR-TV hybrid models can provide improved reconstruction accuracy over total variation and Tikhonov regularization.
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This document contains notes from a signals and systems chapter about the z-transform and representing discrete-time systems using difference equations. It defines the z-transform, provides examples of elementary z-transforms, and discusses using the z-transform to analyze discrete-time linear systems. It also describes representing the input-output relationship of a discrete-time system using a linear constant-coefficient difference equation and gives examples of problems involving determining z-transforms and deriving difference equations from transfer functions.
This document discusses different techniques for phasor estimation from discrete time signals, including the discrete Fourier transform (DFT). It focuses on explaining the one-cycle DFT method. The one-cycle DFT divides the signal into windows of one cycle and applies the DFT to each window to estimate the phasor. It is shown that with each new sample, the phasor estimate from the DFT advances by 45 degrees. The document also discusses applying the one-cycle DFT to signals with harmonic components and estimating sequence components from three-phase signals.
The document proposes a distributed algorithm for network size estimation. Each node in the network runs simple first-order dynamics that exchanges information only with neighbors. The dynamics are designed such that the individual solutions of all nodes will converge to the total number of nodes N in the network. The algorithm provides a deterministic estimate of N and does not require initialization, making it "plug-and-play ready" for dynamic networks where nodes can join or leave over time. It is proven that if the gain k is larger than N^3, the estimates will converge to the true value N within a finite settling time.
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Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
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2. 2 10/17/2021
2
Chapter 2 Discrete-Time Signals and Systems
2.0 Introduction
2.1 Discrete-Time Signals: Sequences
2.2 Discrete-Time Systems
2.3 Linear Time-Invariant (LTI) Systems
2.4 Properties of LTI Systems
2.5 Linear Constant-Coefficient
Difference Equations
3. 3 10/17/2021
3
Chapter 2 Discrete-Time Signals and Systems
2.6 Frequency-Domain Representation
of Discrete-Time Signals and systems
4. 4 10/17/2021
4
2.0 Introduction
Signal: something conveys information
Signals are represented mathematically as
functions of one or more independent variables.
Continuous-time (analog) signals, discrete-
time signals, digital signals
Signal-processing systems are classified along the
same lines as signals: Continuous-time (analog)
systems, discrete-time systems, digital systems
Discrete-time signal
Sampling a continuous-time signal
Generated directly by some discrete-time process
5. 5 10/17/2021
5
2.1 Discrete-Time Signals: Sequences
Discrete-Time signals are represented as
In sampling,
1/T (reciprocal of T) : sampling frequency
integer
:
,
, n
n
n
x
x
period
sampling
T
nT
x
n
x a :
,
Cumbersome, so just use
x n
6. 6 10/17/2021
6
Figure 2.1 Graphical representation
of a discrete-time signal
Abscissa: continuous line
: is defined only at discrete instants
x n
7. 7 Figure 2.2
EXAMPLE Sampling the analog waveform
)
(
|
)
(
]
[ n T
x
t
x
n
x a
n T
t
a
8. 8 10/17/2021
8
Sum of two sequences
Product of two sequences
Multiplication of a sequence by a numberα
Delay (shift) of a sequence
Basic Sequence Operations
]
[
]
[ n
y
n
x
integer
:
]
[
]
[ 0
0 n
n
n
x
n
y
]
[
]
[ n
y
n
x
]
[n
x
11. 11 10/17/2021
11
Basic sequences
Unit step sequence
0
0
0
1
]
[
n
n
n
u
n
k
k
n
u
]
[
0
]
[
]
2
[
]
1
[
]
[
]
[
k
k
n
n
n
n
n
u
]
1
[
]
[
]
[
n
u
n
u
n
First backward difference
0, 0 ,
1, 0
0 0
1 0
since
n
k
when n
k
when n
k
k
k
12. 12 10/17/2021
12
Basic Sequences
Exponential sequences
n
A
n
x
]
[
A and α are real: x[n] is real
A is positive and 0<α<1, x[n] is positive and
decrease with increasing n
-1<α<0, x[n] alternate in sign, but decrease
in magnitude with increasing n
: x[n] grows in magnitude as n increases
1
13. 13 10/17/2021
13
EX. 2.1 Combining Basic sequences
0
0
0
]
[
n
n
A
n
x
n
If we want an exponential sequences that is
zero for n <0, then
]
[
]
[ n
u
A
n
x n
Cumbersome
simpler
15. 15 10/17/2021
15
Exponential Sequences
0
jw
e
j
e
A
A
n
w
A
j
n
w
A
e
A
e
e
A
A
n
x
n
n
n
w
j
n
n
jw
n
j
n
0
0 sin
cos
]
[ 0
0
1
1
1
Complex Exponential Sequences
Exponentially weighted sinusoids
Exponentially growing envelope
Exponentially decreasing envelope
0
[ ] jw n
x n Ae
is refered to
16. 16 10/17/2021
16
Frequency difference between
continuous-time and discrete-time
complex exponentials or sinusoids
n
jw
n
j
n
jw
n
w
j
Ae
e
Ae
Ae
n
x 0
0
0 2
2
]
[
: frequency of the complex sinusoid
or complex exponential
: phase
0
w
0 0
[ ] cos 2 cos
x n A w r n A w n
17. 17 10/17/2021
17
Periodic Sequences
A periodic sequence with integer period N
n
all
for
N
n
x
n
x ]
[
]
[
N
w
n
w
A
n
w
A 0
0
0 cos
cos
integer
,
2
0 is
k
where
k
N
w
0
2 / , integer
N k w where k is
18. 18 10/17/2021
18
EX. 2.2 Examples of Periodic Sequences
Suppose it is periodic sequence with period N
]
[
]
[ 1
1 N
n
x
n
x
4
/
cos
]
[
1 n
n
x
4
/
cos
4
/
cos N
n
n
integer
:
,
4
/
4
/
2
4
/ k
N
n
k
n
0
1, 8 2 /
k N w
2 / ( / 4) 8
N k k
19. 19 10/17/2021
19
Suppose it is periodic sequence with period N
]
[
]
[ 1
1 N
n
x
n
x
8
/
3
cos
8
/
3
cos N
n
n
integer
:
,
8
/
3
8
/
3
2
8
/
3 k
N
n
k
n
16
,
3
N
k
EX. 2.2 Examples of Periodic Sequences
8
/
3
cos
]
[
1 n
n
x
8
3
8
2
0
2 / 2 / (3 / 8)
N k w k
0 0
2 3/ 2 / ( continuous signal)
N w w for
20. 20 10/17/2021
20
EX. 2.2 Non-Periodic Sequences
Suppose it is periodic sequence with period N
]
[
]
[ 2
2 N
n
x
n
x
n
n
x cos
]
[
2
)
cos(
cos N
n
n
2 , :integer,
integer
for n k n N k
there is no N
21. 21 10/17/2021
21
High and Low Frequencies in Discrete-time signal
0
[ ] cos( )
x n A w n
(a) w0 = 0 or 2
(b) w0 = /8 or 15/8
(c) w0 = /4 or 7/4
(d) w0 =
22. 22 10/17/2021
22
2.2 Discrete-Time System
Discrete-Time System is a trasformation
or operator that maps input sequence
x[n] into a unique y[n]
y[n]=T{x[n]}, x[n], y[n]: discrete-time
signal
T{‧}
x[n] y[n]
Discrete-Time System
23. 23 10/17/2021
23
EX. 2.3 The Ideal Delay System
n
n
n
x
n
y d ],
[
]
[
If is a positive integer: the delay of the
system. Shift the input sequence to the
right by samples to form the output .
d
n
d
n
If is a negative integer: the system will
shift the input to the left by samples,
corresponding to a time advance.
d
n
d
n
24. 24 10/17/2021
24
x[m
]
m
n
n-5
dummy index
m
EX. 2.4 Moving Average
2
1
1 2
1 1 2
1 2
1
1
1
1 ... 1 ...
1
M
k M
y n x n k
M M
x n M x n M x n x n x n M
M M
for n=7, M1=0, M2=5
25. 25
Effect of a moving average filter. (Sample values are connected
by straight lines to enable easier viewing of stock exchange
trends)
26. 26 10/17/2021
26
Properties of Discrete-time systems
2.2.1 Memoryless (memory) system
Memoryless systems:
the output y[n] at every value of n depends
only on the input x[n] at the same value of n
2
]
[n
x
n
y
27. 27 10/17/2021
27
Properties of Discrete-time systems
2.2.2 Linear Systems
If
n
y1
T{‧}
n
x1
n
y2
n
x2
T{‧}
n
ay
n
ax T{‧}
n
bx
n
ax
n
x 2
1
3
n
by
n
ay
n
y 2
1
3
T{‧}
n
y
n
y 2
1
n
x
n
x 2
1 T{‧} additivity property
homogeneity or scaling
property
principle of superposition
and only If:
28. 28 10/17/2021
28
Example of Linear System
Ex. 2.6 Accumulator system
n
k
k
x
n
y
n
by
n
ay
k
x
b
k
x
a
k
bx
k
ax
k
x
n
y
n
k
n
k
n
k
n
k
2
1
2
1
2
1
3
3
n
k
k
x
n
y 1
1
n
k
k
x
n
y 2
2
n
x
and
n
x 2
1
for arbitrary
n
bx
n
ax
n
x 2
1
3
when
29. 29 10/17/2021
29
Example 2.7 Nonlinear Systems
Method: find one counterexample
2
2
2
1
1
1
1
counterexample
2
]
[n
x
n
y
For
]
[
log10 n
x
n
y
1
10
log
1
log
10 10
10
counterexample
For
30. 30 10/17/2021
30
Properties of Discrete-time systems
2.2.3 Time-Invariant Systems
Shift-Invariant Systems
0
1
2 n
n
x
n
x
0
1
2 n
n
y
n
y
n
y1
T{‧}
n
x1
T{‧}
31. 31 10/17/2021
31
Example of Time-Invariant System
Ex. 2.8 Accumulator system
n
k
k
x
n
y
0
1 ]
[ n
n
x
n
x
0
1
0
1
1
0
1
n
n
y
k
x
n
k
x
k
x
n
y
n
n
k
n
k
n
k
32. 32 10/17/2021
32
Properties of Discrete-time systems
2.2.4 Causality
A system is causal if, for every choice
of , the output sequence value at
the index depends only on the
input sequence value for
0
n
0
n
n
0
n
n
33. 33 10/17/2021
33
Ex. 2.10 Example for Causal System
Forward difference system is not Causal
Backward difference system is Causal
n
x
n
x
n
y
1
1
n
x
n
x
n
y
34. 34 10/17/2021
34
Properties of Discrete-time systems
2.2.5 Stability
Bounded-Input Bounded-Output (BIBO)
Stability: every bounded input sequence
produces a bounded output sequence.
n
all
for
B
n
x x ,
n
all
for
B
n
y y ,
if
then
35. 35 10/17/2021
35
Ex. 2.11 Test for Stability or Instability
2
]
[n
x
n
y
n
all
for
B
n
x x ,
n
all
for
B
B
n
y x
y ,
2
if
then
is stable
36. 36 10/17/2021
36
Accumulator system
n
k
k
x
n
y
bounded
n
n
n
u
n
x :
0
1
0
0
bounded
not
n
n
n
k
x
k
x
n
y
n
k
n
k
:
0
1
0
0
Ex. 2.11 Test for Stability or Instability
Accumulator system is not stable
37. 37 10/17/2021
37
Properties of Discrete-time systems (Repeat)
2.2.2 Linear Systems
If
n
y1
T{‧}
n
x1
n
y2
n
x2
T{‧}
n
ay
n
ax T{‧}
n
bx
n
ax
n
x 2
1
3
n
by
n
ay
n
y 2
1
3
T{‧}
n
y
n
y 2
1
n
x
n
x 2
1 T{‧} additivity property
homogeneity or scaling
property
principle of superposition
and only If:
38. 38 10/17/2021
38
2.3 Linear Time-Invariant (LTI)
Systems
Impulse response
0
n
n
n
h
n
0
n
n
h
T{‧}
T{‧}
39. 39 10/17/2021
39
LTI Systems: Convolution
k
k
n
k
x
n
x
k
k
k
n
h
n
x
k
n
h
k
x
k
n
T
k
x
k
n
k
x
T
n
y
Representation of general sequence as a
linear combination of delayed impulse
principle of superposition
An Illustration Example(interpretation 1)
41. 41 10/17/2021
41
Computation of the Convolution
reflecting h[k] about the origion to obtain h[-k]
Shifting the origin of the reflected sequence to
k=n
(interpretation 2)
k
k
n
h
k
x
n
y
n
k
h
k
n
h
k
h
k
h
43. 43
Convolution can be realized by
–Reflecting h[k] about the origin to obtain h[-k].
–Shifting the origin of the reflected sequences to k=n.
–Computing the weighted moving average of x[k] by
using the weights given by h[n-k].
44. 44 10/17/2021
44
Ex. 2.13 Analytical Evaluation
of the Convolution
otherwise
N
n
N
n
u
n
u
n
h
0
1
0
1
For system with impulse response
h(k)
0
n
u
a
n
x n
input
Find the output at index n
45. 45
45
0
0
y n n
otherwise
N
n
n
h
0
1
0
1
n
u
a
n
x n
h(k)
0
0
h(n-k) x(k)
h(-k)
0
46. 46 10/17/2021
46
1 0
0, 0 1
n n N n N
a
a
a
n
k
h
k
x
n
y
n
n
k
k
n
k
1
1 1
0
0
h(-k)
0
h(k)
0
47. 47 10/17/2021
47
a
a
a
a
a
a
a
n
k
h
k
x
n
y
N
N
n
n
N
n
n
N
n
k
k
n
N
n
k
1
1
1
1
1
1
1
1
h(-k)
0
h(k)
0
1 0 1
n N n N
49. 49 10/17/2021
49
2.4 Properties of LTI Systems
Convolution is commutative
n
x
n
h
n
h
n
x
h[n]
x[n] y[n]
x[n]
h[n] y[n]
n
h
n
x
n
h
n
x
n
h
n
h
n
x 2
1
2
1
Convolution is distributed over addition
50. 50 10/17/2021
50
Cascade connection of systems
n
h
n
h
n
h 2
1
x [n] h1[n] h2[n] y [n]
x [n] h2[n] h1[n] y [n]
x [n] h1[n] ]h2[n] y [n]
52. 52
52
Stability of LTI Systems
LTI system is stable if the impulse response
is absolutely summable .
k
k
h
S
k
k
k
n
x
k
h
k
n
x
k
h
n
y
x
B
n
x
x
k
y n B h k
Causality of LTI systems 0
,
0
n
n
h
HW: proof, Problem 2.62
53. 53 10/17/2021
53
Impulse response of LTI systems
Impulse response of Ideal Delay systems
,
d d
h n n n n a positive fixed integer
Impulse response of Accumulator
n
u
n
n
k
n
h
n
k 0
,
0
0
,
1
54. 54 10/17/2021
54
Impulse response of Moving
Average systems
otherwise
,
M
n
M
,
M
M
k
n
M
M
n
h
M
M
k
0
1
1
1
1
2
1
2
1
2
1
2
1
55. 55
Impulse response of Forward Difference
n
n
n
h
1
1
n
n
n
h
Impulse response of Backward Difference
56. 56
Finite-duration impulse
response (FIR) systems
The impulse response of the system has
only a finite number of nonzero samples.
The FIR systems always are stable.
otherwise
,
M
n
M
,
M
M
k
n
M
M
n
h
M
M
k
0
1
1
1
1
2
1
2
1
2
1
2
1
n
S h n
such as:
57. 57
Infinite-duration impulse
response (IIR)
The impulse response of the system is
infinite in duration.
n
u
n
n
k
n
h
n
k 0
,
0
0
,
1
n
u
a
n
h n
n
S h n
Stable IIR System:
1
a
58. 58
Equivalent systems
1 1
h n n n n
1 1 1
n n n n n
59. 59
Inverse system
n
n
u
n
u
n
n
n
u
n
h
1
1
n
n
h
n
h
n
h
n
h i
i
60. 60
2.5 Linear Constant-Coefficient
Difference Equations
M
m
m
N
k
k m
n
x
b
k
n
y
a
0
0
An important subclass of linear time-
invariant systems consist of those
system for which the input x[n] and
output y[n] satisfy an Nth-order linear
constant-coefficient difference equation.
61. 61
Ex. 2.14 Difference Equation
Representation of the Accumulator
,
n
k
y n x k
1
1
k
n
y n x k
1
1
n
y
n
x
k
x
n
x
n
y
n
k
n
x
n
y
n
y
1
62. 62
Block diagram of a recursive
difference equation representing an
accumulator
1
y n y n x n
63. 63
Difference Equation
Representation of the System
An unlimited number of distinct
difference equations can be used to
represent a given linear time-invariant
input-output relation.
64. 64
Solving the difference equation
Without additional constraints or
information, a linear constant-
coefficient difference equation for
discrete-time systems does not provide
a unique specification of the output for
a given input.
M
m
m
N
k
k m
n
x
b
k
n
y
a
0
0
65. 65
Solving the difference equation
Output:
n
y
n
y
n
y h
p
Particular solution: one output sequence
for the given input
n
yp
n
xp
Homogenous solution: solution for
the homogenous equation( ):
n
yh
0
0
N
k
h
k k
n
y
a
N
m
n
m
m
h z
A
n
y
1
where is the roots of
m
z 0
0
N
k
k
k z
a
0
x n
M
m
m
N
k
k m
n
x
b
k
n
y
a
0
0
66. 66
Example 2.16 Recursive Computation of
Difference Equation
1 , , 1
y n ay n x n x n K n y c
K
ac
y
0
aK
c
a
K
ac
a
ay
y
2
0
0
1
K
a
c
a
aK
c
a
a
ay
y 2
3
2
0
1
2
K
a
c
a
K
a
c
a
a
ay
y 3
4
2
3
0
2
3
1
0
n n
y n a c a fo
K r n
67. 67
Example 2.16 Recursive Computation of
Difference Equation
n
x
n
y
a
n
y
1
1
c
a
x
y
a
y 1
1
1
1
2
c
a
c
a
a
x
y
a
y 2
1
1
1
2
2
3
1
1
n
y n a c for n
c
a
c
a
a
x
y
a
y 3
2
1
1
3
3
4
1
n n
y n a c Ka for l
n l n
u a
1
for n
c
y
n
K
n
x
n
x
n
ay
n
y
1
1
68. 68
Periodic Frequency Response
The frequency response of discrete-time
LTI systems is always a periodic function of
the frequency variable with period
w 2
2 2
j w j w n
n
H e h n e
2 2
j w jwn j n jwn
e e e e
2
j w jw
H e H e
2
,
j w r jw
H e H e for r an integer
Signal Processing - Dr. Arif Wahla
10/17/2021
69. 69
Periodic Frequency Response
The “low frequencies” are frequencies
close to zero
The “high frequencies” are frequencies
close to
More generally, modify the frequency with
, r is integer.
2 r
jw
e
H
or w
0 2
w
We need only specify over
Signal Processing - Dr. Arif Wahla
10/17/2021
74. 74
Example 2.20 Frequency Response of
the Moving-Average System
otherwise
,
M
n
M
,
M
M
n
h
0
1
1
2
1
2
1
1
1 2
1 2
2
1
1
2
1
1
1
1 1
jw
M
n M
jw M
jwn
H e
M M
jwM
jw
M M
e
e e
e
75. 75
Impulse response and
Frequency response
The frequency response of a LTI
system is the Fourier transform of the
impulse response.
jw jwn
n
H e h n e
dw
e
e
H
n
h jwn
jw
2
1