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ISSN No: 2456
InternationalResearch
Application of Convolution Theorem
Associate Professor, Yogananda College of Engineering & Technology, Jammu
ABSTRACT Generally it has been noticed that differential equation is solved typically. The Laplace transformation makes it easy to solve. The Laplace transformation is applied in different areas of science, engineering and technology. The Laplace transformation is applicable in so many fields. Laplace transformation is usesolving the time domain function by converting it into frequency domain. Laplace transformation makes it easier to solve the problems in engineering applications and makes differential equations simple to solve. In this paper we will discuss how to foconvolution theorem holds the Commutative property, Associative Property and Distributive Property.
Keywords: Laplace transformation, Inverse Laplace transformation, Convolution theorem
INTRODUCTION:
Laplace transformation is a mathematical tool which is used in the solving of differential equations by converting it from one form into another form. Generally it is effective in solving linear differential equation either ordinary or partial. It reduces ordinary differential equation into algebraic equation. Ordinary linear differential equation with constant coefficient and variable coefficient can be easily solved by the Laplace transformation method without finding the generally solution and the arbconstant. It is used in solving physical problems. this involving integral and ordinary differential equation with constant and variable coefficient.
It is also used to convert the signal system in frequency domain for solving it on a simple and easy way. It has some applications in nearly all engineering disciplines, like System Modeling, Analysis of Electrical Circuit, Digital Signal Processing, Nucle
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International Journal of Trend in Scientific Research and Development (IJTSRD)
International Open Access Journal
Application of Convolution Theorem
Dr. Dinesh Verma Yogananda College of Engineering & Technology, Jammu
Generally it has been noticed that differential equation solved typically. The Laplace transformation makes
it easy to solve. The Laplace transformation is applied in different areas of science, engineering and technology. The Laplace transformation is applicable in so many fields. Laplace transformation is used in solving the time domain function by converting it into frequency domain. Laplace transformation makes it easier to solve the problems in engineering applications and makes differential equations simple to solve. In this paper we will discuss how to follow convolution theorem holds the Commutative property, Associative Property and Distributive Property.
Laplace transformation, Inverse Laplace
Laplace transformation is a mathematical tool which is used in the solving of differential equations by converting it from one form into another form. Generally it is effective in solving linear differential equation either ordinary or partial. It reduces an ordinary differential equation into algebraic equation. Ordinary linear differential equation with constant coefficient and variable coefficient can be easily solved by the Laplace transformation method without finding the generally solution and the arbitrary constant. It is used in solving physical problems. this involving integral and ordinary differential equation
It is also used to convert the signal system in frequency domain for solving it on a simple and easy way. It has some applications in nearly all engineering disciplines, like System Modeling, Analysis of Electrical Circuit, Digital Signal Processing, Nuclear
Physics, Process Controls, Applications in Probability, Applications in Physics, Applications in Power Systems Load Frequency Control etc.
DEFINITION
Let F (t) is a well defined function of t for all t The Laplace transformation of F (t), denotedor L {F (t)}, is defined as
L {F (t)} =β« π πΉ(π‘
Provided that the integral exists, i.e. convergent. If the integral is convergent for some value ofLaplace transformation of F (t) exists otherwise not. Where π the parameter which may be real or complex number and L is is the Laplace transformation operator.
The Laplace transformation of F (t) i.e.
β« π πΉ(π‘)ππ‘ exists for π>a, if
F (t) is continuous andlim β
should however, be keep in mind that above condition are sufficient and not necessary.
Inverse Laplace Transformation
Definition:
If be the Laplace Transformation of a function F(t),then F(t) is called the Inverse Laplace transformation of the function f(p) and is written as πΉ(π‘) = πΏ {π(π)} , πβπππ πΏ
πππ£πππ π πΏππππππ π‘ππππ ππππππ‘πππ
General Property of inverse Laplace transformation,
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Yogananda College of Engineering & Technology, Jammu, India
Physics, Process Controls, Applications in Probability, Applications in Physics, Applications in Power Systems Load Frequency Control etc.
Let F (t) is a well defined function of t for all t β₯ 0. The Laplace transformation of F (t), denoted by f (π)
(π‘)ππ‘ = π(π)
Provided that the integral exists, i.e. convergent. If the integral is convergent for some value of π , then the Laplace transformation of F (t) exists otherwise not.
the parameter which may be real or complex number and L is is the Laplace transformation
The Laplace transformation of F (t) i.e. >a, if
{π πΉ(π‘)} is finite. It should however, be keep in mind that above condition are sufficient and not necessary.
Inverse Laplace Transformation
If be the Laplace Transformation of a function F(t),then F(t) is called the Inverse Laplace
he function f(p) and is written as ππ ππππππ π‘βπ
π‘ππππ ππππππ‘πππ.
General Property of inverse Laplace transformation,
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(1) π³πππππππ π·πππππππ:
πΌπ π πππ π πππ ππππ π‘πππ‘π πππ ππ
πΏ {π(π)} = πΉ(π‘)ππππΏ{πΊ(π‘)} = π(π)
π‘βππ,
πΏ [π π(π) + π π(π)]= π πΏ [π(π)] + π πΏ [π(π)]
(2)πΉπππ π‘ πβπππ‘πππ πππππππ‘π¦:
πππΏ {π(π)} = πΉ(π‘), π‘βππ
πΏ {π(π β π)} = π πΉ(π‘), (3)πΆβππππ ππ πππππ πππππππ‘π¦:
πππΏ {π(π)} = πΉ(π‘), π‘βππ
πΏ {π(ππ)} =1
ππΉ
π‘
π,
(4)πΌππ£πππ π πΏππππππ πππππ ππππππ‘πππ ππ
πππππ£ππ‘ππ£π:
πππΏ {π(π)} = πΉ(π‘), π‘βππ
πΏ β{ ( )}
= π‘πΉ(π‘)
πΏ β{ ( )}
= (β1) π‘ πΉ(π‘),
π€βπππ π = 123 β¦ β¦ β¦
(5)πΌππ£πππ π πΏππππππ πππππ ππππππ‘πππ ππ
πππ‘πππππ:
πππΏ {π(π)} = πΉ(π‘), π‘βππ
πΏ π(π)ππ = πΉ(π‘)
π‘
(6)πΌππ£πππ π πΏππππππ πππππ ππππππ‘πππ ππ
πππ£ππ πππ ππ¦ π:
πππΏ {π(π)} = πΉ(π‘), π‘βππ
πΏπΉ(π)
π = π(π’)ππ’
The convolution of two given functions acting an essential role in a number of physical applications. It is usually convenient to determination a Laplace transformation into the product of two transformations
when the inverse transform of both transforms are known. Convolution is used to get inverse Laplace transformation in solving differential equations and integral equations.
If π» (π‘)πππ π» (π‘) ππ π‘π€π ππ’πππ‘ππππ ππ ππππ π π΄
πππ ππβ (π ) = πΏ{π» (π‘)} , β (π ) = πΏ{π» (π‘)}.
πβππ π‘βπ ππππ£πππ’π‘πππ ππ π‘βππ π π‘π€π
ππ’πππ‘ππππ π» (π‘)πππ π» (π‘) ,
π‘ > 0 ππ πππππππ ππ¦ π‘βπ πππ‘πππππ
{π» β π» }(π‘) = π» (π‘)π» (π‘ β π¦)ππ¦
ππ π» (π‘ β π¦)π» (π¦)ππ¦
Which of course exists if π» (π‘)πππ π» (π‘) are piecewise continuous .the relation is called the convolution or falting of π» (π‘)πππ π» (π‘).
Proof of convolution theorem:
By the definition of Laplace Transformation πΏ( π» β
π» )(π‘) = β« π {(π» β π» )π‘}ππ‘
= π π» (π‘)π» (π‘ β π¦)ππ¦ ππ‘
Where the double integral is taken over the infinite region in the first quadrant deceitful linking the limitπ¦ = 0 π‘π π¦ = π‘.
Now order of integral are changing
π π» (π¦)ππ¦ π ( )π» (π‘ β π¦)ππ‘
π‘ β π¦ = π’ β ππ‘ = ππ’
π€βππ π‘βπ πππππ‘ ππ π‘ ππ π¦ π‘βππ π‘βπ πππππ‘ ππ π’
ππ 0 πππ π€βππ π‘βπ πππππ‘ ππ π‘ ππ β π‘βππ π‘βπ
πππππ‘ ππ π’ ππ β.
πππ€ ππππ ππππ£π
π π» (π¦)ππ¦ π π» (π’)ππ’
β (π)β (π)
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Hence
πΏ( π» β π» )(π‘) = β (π)β (π)
Properties of convolution theorem: convolution theorem holds the following Properties:
(1) Commutative Property: property states that there is no alter in result from side to side the numbers in an appearance are exchange. Commutative property holds for addition and multiplication but not for subtraction and division.
π΄ππππ‘πππ π» + π» = π» + π»
ππ’ππ‘πππ‘πππ π» βπ» β π» β π»
ππ’ππ‘πππππππ‘πππ π» β π» = π» β π»
π·ππ£ππ πππ π» Γ· π» β π» Γ· π»
Now π€π π€πππ ππππ£π π‘βππ‘ π‘βπ πΆππππ’π‘ππ‘ππ£π
πππππππ‘π¦ πππ ππ’ππ‘πππππππ‘πππ
{π» β π» } = {π» β π» }
π·ππππ (π):
By the definition of convolution theorem
π» β π» = β« π» (π‘)π» (π‘ β π¦)ππ¦
πΏππ‘ π‘ β π¦ = π’ β ππ‘ = βππ’,
π€βππ the πππππ‘ ππ π¦ ππ 0 π‘βππ π’ ππ π¦
πππ π€βππ π¦ ππ π‘ π‘βππ π’ ππ 0.
π» β π» = β« π» (π‘ β π’)π» (π’)ππ’
π» β π» = β« π» (π‘ β π’)π» (π’)ππ’
π» β π» = β« π» (π’)π» (π‘ β π’)ππ’
π» β π» = π» β π»
The Convolution of π» πππ π» follow the commutative property.
(2) Associative Property: Associative Property states that the order of grouping the numbers does not matter. This law holds for addition and multiplication but not for subtraction and division.
π΄ππππ‘πππ π» +( π» + π» ) = (π» + π» ) + π»
ππ’ππ‘πππ‘πππ π» β( π» β π» ) = (π» β π» ) β π» ππ’ππ‘πππππππ‘πππ π» β ( π» β π» ) = (π» β π» ) β π»
π·ππ£ππ πππ π» Γ· ( π» Γ· π» ) = (π» Γ· π» ) Γ· π»
Now we will see that how to convolution theorem follow the Associative property for multiplication
π» β ( π» β π» ) = (π» β π» ) β π»
πππ‘ π» β π» = π»
πππ€, π» = π» β π» = π» (π¦)π» (π‘ β π¦)ππ¦
From above the commutative property
π» β π» = π» β π»
πβπππππππ π» β π» = π» β π»
ππ, π» β π» = π» (π¦)π» (π‘ β π¦)ππ¦
Hence , π» β π» = π» (π§)π» (π‘ β π§)ππ§
π» β π» = π» (π§) π» (π¦)π» (π‘ β π§
β π¦)ππ¦ ππ§
Change of order of integration
π» β π» = β« π» (π§) β« π» (π¦)π» (π‘ β π§ β
π¦)ππ§ ππ¦ = π» β (π» β π» )
π»ππππ, π» β ( π» β π» ) = (π» β π» ) β π»
Distributive Property: The property with respect to addition is used to eliminate the bracket in an expression. The distributive property states that each term inside the bracket should be multiplied with the term outside. The property is very useful while simplifying the expressions and solving the complicated equations.
Distributive property over addition
π» β (π» + π» ) = π» β π» + π» β π»
Here the terms which are inside the bracket (π» πππ π» ) are multiplied with the external terms (while is π» ).
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Now we will see that how to convolution theorem follow the Distributive property for multiplication
π» β (π» + π» ) = β« π» (π¦)[π» (π‘ β π¦) + π» (π‘ β
π¦)]ππ¦
= β« π» (π¦)π» (π‘ β π¦)ππ¦ + β« π» (π¦)π» (π‘ β
π¦)ππ¦
π» β π» + π» β π»
π»ππππ , π» β (π» + π» ) = π» β π» + π» β π»
CONCLUSION:
In this paper we have discussed the Applications of convolution theorem of Laplace transformation i.e. how to follow the convolution theorem holds the Commutative property, Associative Property and Distributive Property. The primary use of Laplace transformation is converting a time domain functions into frequency domain function. Here, Some Property of inverse Laplace transformations like, linearity property, First shifting property, Change of scale property, Inverse Laplace transformation of derivative etc. has been discussed.
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