Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

convolution and LTI systems

Status
Not open for further replies.

purnapragna

Advanced Member level 4
Joined
Oct 21, 2005
Messages
107
Helped
6
Reputation
14
Reaction score
3
Trophy points
1,298
Activity points
2,287
Hi i want to know :
Is the convolution integral is applicable only to LTI systems? I mean what is the condition that has to be imposed on the system so that to find the impulse response of it we can use convolution integral. To be more eloborate, should the system has to satisfy both the properties or any one is enough to find its impulse response using the convolution integral?

thnx

purna!
 

claudiocamera

Full Member level 4
Joined
Aug 19, 2005
Messages
225
Helped
27
Reputation
54
Reaction score
6
Trophy points
1,298
Location
Salvador-BA-Brazil
Activity points
4,282
I dont think convolution is applicable only to LTI system. See adaptive filters theory for instance: The output signal, is the convolution in time of the input signal with the adaptive filters coeficient, in spite of the fact that the filters coeficient varies with time, obviously an adaptive filters is not invariant in time, and convolution operation remain applicable. It is just an oppinion, I wouldn't tell you that it is 100% right, counteroppinions are wellcome.
 

com2005

Newbie level 4
Joined
Feb 22, 2006
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
about the adaptive filters:
in an instance ur adaptive filter is Time-Invariant (TI) so u can use convolution.
but in the system like :
y = t.x(t)
ur sys. all the time is T-Variant.
and I think that convolution is only applicable to LTI systems.
bye
 

djdansays

Newbie level 1
Joined
Jan 28, 2006
Messages
0
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,280
Activity points
1,292
purnapragna said:
Hi i want to know :
Is the convolution integral is applicable only to LTI systems? I mean what is the condition that has to be imposed on the system so that to find the impulse response of it we can use convolution integral. To be more eloborate, should the system has to satisfy both the properties or any one is enough to find its impulse response using the convolution integral?

thnx

purna!

LTI systems as you know are Linear Time Invariant systems. There are 2 types of signals-discrete and continuous signals. Convolution Integral is applicable to continuous signals and convolution sum is applicable to discrete signals. To know more about these refer Signals and Systems by Simon Haykins and Barry Van Veen.
Hope this has answered your question.
 

purnapragna

Advanced Member level 4
Joined
Oct 21, 2005
Messages
107
Helped
6
Reputation
14
Reaction score
3
Trophy points
1,298
Activity points
2,287
no it did not answer my question. Please read it more clearly.

thnx

purna!
 

vahidkh6222

Full Member level 2
Joined
Oct 11, 2005
Messages
137
Helped
6
Reputation
12
Reaction score
0
Trophy points
1,296
Activity points
2,419
yes, it is impossible.
we directly use both of the linearity and time-invariency properties of LTI systems to prove the theorem. (remember The Sifting Property of the Impulse function that help us to build other signals,based on integral of impulses...)
so, it is impossible to use convoloution integral for non-LTI systems.
take a look: https://cnx.org/content/m10085/latest/
 

sivani_vs

Junior Member level 3
Joined
Feb 10, 2006
Messages
31
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,530
I feel that convolution integral is valied only for LTI systems and not for all systems.
 

dreamcard

Member level 2
Joined
Sep 11, 2004
Messages
49
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
309
conv int is only for LTI
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top