Notebook : Signals and systems

Results for Signals and systems

Signals and Systems Notes-1

Sikha January 18, 2016

What is Signal?

Signal is a time varying physical phenomenon which is intended to convey information.

Signal is a function of time.

Signal is a function of one or more independent variables, which contain some information.

Example: voice signal, video signal, signals on telephone wires etc.

Note: Noise is also a signal, but the information conveyed by noise is unwanted hence it is considered as undesirable

What is System?

System is a device or combination of devices, which can operate on signals and produces corresponding response. Input to a system is called as excitation and output from it is called as response.

For one or more inputs, the system can have one or more outputs.

Example: Communication System

white'>Signal is a function of one or more independent variables, which contain some information.

Example: voice signal, video signal, signals on telephone wires etc.

Note: Noise is also a signal, but the information conveyed by noise is unwanted hence it is considered as undesirable

Signals and Systems Notes-1

Reviewed by Sikha on January 18, 2016 Rating: 5

Gate 2016 preparation-Signals and Systems

Sikha January 01, 2016

· Continuous and Discrete Time Signals

We need to study here the impact of shifting and scaling operations on the waveform of the signals, Refer in in Oppenheim book.
classifications of signals based on different criteria like:

a) Periodic and Aperiodic Signal

b) Even and Odd Signal

c) Power and Energy Signals

Linear Time Invariant Systems

This is the most important part in Signals and Systems .

impulse response -The impulse response is useful when there is a connection of more than one systems like in cascade configuration or parallel one but you need to remember the equivalent impulse response of thesystem.

convolution methodology

by the help of convolution we can compute output at some points only and verify with the options given and save time.

properties of Systems like

a) Causality,

b) Time-Invariance,

c) Stability,

d) Linearity

e) and we need to study the criterion to determine each of these properties for a system

Fourier Series

two types of Fourier Series and Transforms for Continuous Time Signals and other for Discrete Time Signals. for EEE GATE course discrete time Fourier Series is not included and hence they only need to prepare only continuous time fourier series.

Need to remember two things or rather three things which are:

Analysis and Synthesis Equations

Properties of Transforms
Common Transform Pairs

Fourier Transform

need to remember that Fourier Transform exists for Aperiodic Signals
Fourier Series for Periodic Signals
Fourier Transform approaches Fourier Series for periodic Signals.

Also, one more important thing is the fourier transform of rectangular and triangular functions and the converse also which can easily be computed using duality property.

Laplace Transform

Laplace Transforms only exist for Continuous Time
The concept of Region of Convergence (ROC) as the same transform may have different inverses based on different ROCs.
no Laplace Transform is complete without
the concept of Initial Value and Final Value Theorem
Before applying final value theorem, please verify the stability.

Z-Transform

Z-Transform is for the discrete time signals
some striking differences also like in case of Final Value Theorem
the concept of Stability and Causality
pole-zero plot is given and system properties need to be identified.

Sampling

important concept in Sampling is for the Nyquist Rate and Nyquist Frequency
practice drawing one or two waveforms where sampling frequency is less than Nyquist Frequency
Band-Pass Sampling Theorem as that may also be asked.

Gate 2016 preparation-Signals and Systems

Reviewed by Sikha on January 01, 2016 Rating: 5

Signals and Systems 2nd Edition by Alan V. Oppenheim -download free

Sikha November 03, 2015

This comprehensive book on signals and systems develops continuous-time and discrete-time concepts/methods in parallel, highlighting the similarities and differences. It also features introductory treatments of the applications of these basic methods in areas such as filtering, communication, sampling, discrete-time processing of continuous-time signals, and feedback.

Review:

The second edition of this well-known and highly regarded text can be used as the basis for a one- or two-semester undergraduate course in signals and linear systems theory and applications. Topics include basic signals and systems concepts, linear time-invariant (LTI) systems, Fourier representations of continuous-time and discrete-time signals, the CT and DT Fourier transforms, and time- and frequency-domain analysis methods. The author emphasizes applications of the theory through numerous examples in filtering, sampling, communications, and feedback. The parallel development of continuous-time and discrete-time frequency domain methods allows the reader to apply insights and intuition across the two domains. It also facilitates a deeper understanding of the material by bringing into focus the similarities and differences between the two domains. The text also includes introductory chapters on communication systems and control theory. This book assumes that you have a background in calculus as well as exposure to complex numbers and elementary differential equations. Because of its thoroughness and unhurried pace, this text is highly recommended for students and those interested in self-study.

From the Publisher:

This comprehensive exploration of signals and systems develops continuous-time and discrete-time concepts/methods in parallel -- highlighting the similarities and differences -- and features introductory treatments of the applications of these basic methods in such areas as filtering, communication, sampling, discrete-time processing of continuous-time signals, and feedback. Relatively self-contained, the text assumes no prior experience with system analysis, convolution, Fourier analysis, or Laplace and z-transforms.