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SIGNALS & SYSTEMSAn Introduction

Presented By:Loveleen Kaur

Asst. Professor

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COURSE CODE:ECE209

TEXT BOOKS

Alexander, Sadiku Fundamentals of Electric Circuits, McGraw

Hill Publications, Latest Edition.

Other Specific Book:

Van Valkenberg, Network Analysis and Synthesis, PHI.

Shyammohan and Sudhakar, Circuits and Networks, Tata

McGraw Hill.

B. P. Lathi, Signal and Systems, Oxford,3e.

Phillips, Parr, Riskin ,Signals, Systems and Transforms, Pearson

Education

A. Chakrabarti,Circuit Theory, Dhanpat Rai & Co. 3rd / TMH,

2007

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ABOUT THE SUBJECT

Signals

Systems

Transforms

Networks

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To be transmitted, data mustbe transformed to

electromagnetic signals.

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SIGNAL

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SIGNAL It is the function that describes the variation of a physical

variable with respect to independent variable( time, space

etc.) in a physical process.

Mathematically,

S=f(x)

Where S is signal /function and x independent variable.

Examples:

1) Change in temperature sensed by the sensor placed in boiler.

T=f(t)

Here, time t is independent variable.

t (msec) 1 2 3 4

Temp(C) 29 51 18 50

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ANALOG AND DIGITALANALOG AND DIGITAL

DataData cancan bebe analoganalog oror digitaldigital.. TheThe termterm analoganalog

datadata refersrefers toto informationinformation thatthat isis continuouscontinuous;;

digitaldigital datadata refersrefers toto informationinformation thatthat hashas discretediscretestatesstates.. AnalogAnalog datadata taketake onon continuouscontinuous valuesvalues..

DigitalDigital datadata taketake onon discretediscrete valuesvalues..

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ANALOG AND DIGITAL DATA

Data can be analog or digital.

Analog data are continuous and take continuous values.

Digital data have discrete states and take discrete values.

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ANALOG AND DIGITAL SIGNALS

Signals can be analog or digital.

Analog signals can have an infinite number of

values in a range.

Digital signals can have only a limitednumber of values.

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COMPARISON OF ANALOG AND DIGITAL

SIGNALS

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APPLICATION AREAS

Control

Communications

Signal Processing

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CONTROL APPLICATIONS

Industrial control and automation (Control thevelocity or position of an object)

Examples:Controlling the position of a valve orshaft of a motor

Important Tools:

y Time-domain solution of differential equations

y Transfer function (Laplace Transform)

y Stability

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COMMUNICATION APPLICATIONS

Transmission of information (signal) over a

channel

The channel may be free space, coaxial cable,

fiber optic cable Akey component of transmission: Modulation

(Analog and Digital Communication)

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SIGNAL PROCESSING APPLICATIONS

Signal processing=Application ofalgorithms to modify signals in a way tomake them more useful.

Goals:y Efficient and reliable transmission, storage

and display of information

y Information extraction and enhancement

Examples

:

y Speech and audio processing

y Multimedia processing (image and video)

y Biological signal analysis

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CLASSIFICATION OF SIGNALS

Continuous and Discrete time signals

Continuous valued and discrete valued signal

Periodic and non-periodic signals

Even and odd signals

Deterministic and random signals