Sketching Signal x(t): 2^(-t*u(t))

  • Thread starter drkidd22
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In summary, the "u(t)" in the function "2^(-t*u(t))" represents the unit step function, which acts as a switch to turn the function on at t = 0. The base of the function is often 2 because it is a convenient and commonly used number in signal processing. The graph of the function is a decaying exponential with a steep initial drop at t = 0 and gradually approaching 0 as t increases. This function can be applied in real-world situations to model decay in physical systems. It can also be modified by changing the base or adding other terms to the exponent to alter the decay rate or create different shapes of decay curves.
  • #1
drkidd22
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Homework Statement



Sketch the signal:
x(t) = 2^(-t*u(t)) over (-1 < t < 1)

The Attempt at a Solution


Attached is an excel fine with my work out. I want to know is it is correct.
 

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  • HW#1.xls
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  • #2
It is simplest to think of this as a piecewise function
[tex] x(t) = \begin{cases}
1, t < 0 \\
2^{-t}, t>0
\end{cases}[/tex]
then
[tex] x(t)^2 = \begin{cases}
1, t < 0 \\
2^{-2t}, t>0
\end{cases}[/tex]
so when you integrate x(t)^2 from -1 to 1, it breaks apart into two integrals. One is from -1 to 0 of 1, and the other is from 0 to 1 of 2^{-2t}.
 

1. What is the function of "u(t)" in "2^(-t*u(t))"?

The "u(t)" in the function represents the unit step function, which is equal to 0 for all negative values of t and equal to 1 for all positive values of t. It essentially serves as a switch to turn the function on at t = 0.

2. Why is the base of the function 2?

The base of the function can be any positive number, but 2 is often used because it is a convenient and commonly used number in signal processing.

3. What does the function graph look like?

The graph of the function will be a decaying exponential with a steep initial drop at t = 0, gradually approaching 0 as t increases.

4. How can this function be applied in real-world situations?

This function can be used to model the decay of certain physical systems, such as radioactive decay or the discharge of a capacitor in an electrical circuit.

5. Can this function be modified for different purposes?

Yes, the function can be modified by changing the base or adding other terms to the exponent. This can alter the rate of decay or create different shapes of decay curves.

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