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[moved] Question about periodic signals

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PalTaj

Newbie level 3
Hello
can you anyone help me in solving these ?

shahbaz.ele

Advanced Member level 1
Re: Question about periodic signals

If you know MATLAB.
one method is to plot in MATLAB.
and see whether its periodic or not, and measure time period.
without solving mathematics.

PalTaj

Newbie level 3
Re: Question about periodic signals

If you know MATLAB.
one method is to plot in MATLAB.
and see whether its periodic or not, and measure time period.
without solving mathematics.

but i need the mathematic solving

c_mitra

Advanced Member level 6
Re: Question about periodic signals

The questions are very simple and I wonder why you cannot answer them yourself. I guess you have been asked to answer these question as part of a class work, right?

These formula and equations must have been taught in the class. If you have any specific difficulty in understanding, please feel free to ask ad libitum.

If someone else solves (gives answer on your behalf) these, then you will learn close to nil and that is not a real help.

Please try yourself first and if you have any difficulty, please do ask till you are clear.

begin at the beginning: What is a periodic function?

PalTaj

Newbie level 3
Re: Question about periodic signals

can you provide me with a good source to study it ?
like i really want to understand the concept

shahbaz.ele

Advanced Member level 1
Re: Question about periodic signals

any signal processing/ signal system book,
may be the one you are studying one.

CataM

Advanced Member level 4
Re: Question about periodic signals

You did not study it on the course? Or the teacher did not provide book for it?

A function is periodic if f(z)=f(z+T) with z being a complex variable.

To help you out, for the exponentials use Euler's formula.

For the c) function, I will help you with this.

Consider f(x)=sin(x)/x = sinc(x) (in is not exactly what you have but works since you multiply by a constant)

Let assume it is periodic => f(x)=f(x+T). T is the period which can be took for whatever interval you want, I will take for the inverval [0,T] meaning f(0)=f(0+T) for x=0.

Ok, so lets start..

f(0)=f(T) <=> 1=sin(T)/T <=> sin(T)=T => that equation has one and only one solution for T=0, meaning the function is periodic with period T=0 meaning it is not periodic.

ustinoff

Member level 2
Re: Question about periodic signals

any signal processing/ signal system book,
may be the one you are studying one.

Richard Lyons "Understanding digital signal processing" or any math book for high school.

Or: MIT OpenCourse Ware, Prof. Gilbert Strang's course "Highlights of calculus"

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