How to find the impulse function?

In summary, to find the impulse function, one typically starts by recognizing it as the limit of a sequence of functions that converge to a Dirac delta function. This can involve using a narrow, tall pulse whose area remains constant as its width approaches zero. Alternatively, the impulse function can be derived from the properties of linear systems in signal processing, where it acts as an identity element under convolution. Various mathematical approaches, such as using Fourier transforms, can also help identify and work with the impulse function in different contexts.
  • #1
billtodd
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Homework Statement
I found the impulse function in the frequency space to be: ##H(\omega)=1-\exp(2i\omega )##, and I want to find its ##h[n]##.
Relevant Equations
Fourier analysis.
So I have: ##H(\omega)=(\exp(-i\omega)-\exp(i\omega))\exp(i\omega)##, I denote by ##Z(\omega)=\exp(i\omega)##, to get: ##H(\omega)=Z(-\omega)Z(\omega)-Z(\omega)^2##, now, I want to find ##h[n]##, I think it should be: ##h[n]=z[-n]*z[n]+z[n]*z[n]##.

But I am not sure how to calculate the discrete convolutions, any help?

Thnaks!
 
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  • #2
Transform 1 and -e^2i##\omega## each and sum them up. It does not work?
 
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  • #3
It's ok, thanks!
 
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FAQ: How to find the impulse function?

What is an impulse function?

An impulse function, often represented as δ(t), is a mathematical function that models an idealized instantaneous spike or burst of energy at a specific point in time. It is used in various fields such as physics and engineering to represent phenomena like forces applied over a very short duration or signals in systems.

How is the impulse function mathematically defined?

The impulse function δ(t) is defined such that it is zero for all values of t except at t = 0, where it is considered to be infinite. The integral of the impulse function over its entire domain is equal to one: ∫δ(t) dt = 1. This property makes it useful in systems analysis and signal processing.

How can I find the impulse function in a given system?

To find the impulse function for a given system, you can analyze the system's response to an input. Use the system's differential equation and apply the Laplace transform. The impulse response of the system can be obtained by taking the inverse Laplace transform of the system's transfer function, which describes how the system responds to an impulse input.

What is the relationship between the impulse function and the step function?

The impulse function is the derivative of the step function. Mathematically, if u(t) is the unit step function, then δ(t) = du(t)/dt. This relationship indicates that the impulse function represents an instantaneous change in the value of the step function, which jumps from 0 to 1 at t = 0.

Can the impulse function be used in numerical simulations?

Yes, the impulse function can be approximated in numerical simulations using finite-duration pulses or delta-like functions. In practice, a narrow Gaussian function or a rectangular pulse can be used to simulate the impulse function over a small time interval, allowing for the analysis of systems that respond to these approximations in a similar manner to how they would respond to an ideal impulse.

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