Find Y(s)/X(s) for y(t) = u(t - a).x(t)

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Discussion Overview

The discussion revolves around finding the ratio Y(s)/X(s) for the function y(t) = u(t - a) . x(t), where u(t) is a unit step function. The focus is on the application of Laplace transforms and the implications of convolution in the frequency domain.

Discussion Character

  • Technical explanation, Mathematical reasoning, Debate/contested

Main Points Raised

  • One participant suggests that the Laplace transforms X(s) and Y(s) refer to the transforms of x(t) and y(t), respectively, and questions whether convolution is necessary.
  • Another participant proposes that the Laplace transform of y(t) can be directly calculated as e^{-s}X(s) or obtained from a table of transforms.
  • A subsequent reply seeks clarification on whether the correct expression is e^{-as}X(s), noting that this would correspond to the Laplace transform of x(t - a).
  • Another participant references an article claiming that Y(s) should be expressed as Y(s) = e^{-as} . Laplace{x(t + a)}.

Areas of Agreement / Disagreement

Participants express differing views on the correct approach to finding Y(s)/X(s), with no consensus reached on the necessity of convolution or the correct formulation of the Laplace transform.

Contextual Notes

There are unresolved assumptions regarding the definitions of the functions involved and the conditions under which the transforms are applied. The discussion also reflects varying interpretations of the Laplace transform properties.

Debdut
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y(t) = u(t - a) . x(t)
u(t) is a unit step function. I have to find Y(s)/X(s). Do I have to do convolution in frequency domain?
 
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First, are we to assume that "X(s)" and "Y(s)" are the Laplace transforms of x(t) and y(t)? I don't see any reason why you just cannot calculate directly that the Laplace transform of y(t) is e^{-s}X(s) or get it from a table of transforms.
 
Thanks for the quick reply.
Do you mean e-asX(s). But that is the laplace of x(t - a).
Am I wrong?
 
Found an article where they're saying Y(s) should be Y(s) = e-as . Laplace{x(t + a)}
 

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