Signals: Determing x(t) (Time reversal, shifting, expansion)

In summary, time reversal in signal processing involves reversing the order of a signal's samples or values, while shifting a signal changes its time domain representation by delaying or advancing it. Time reversal and time shifting are inverse operations, and both can be applied to any type of signal. Expanding a signal in the time domain results in a corresponding compression or expansion of its frequency domain representation, affecting its frequency content. These operations can be applied to any type of signal, including continuous-time signals, discrete-time signals, and digital signals.
  • #1
jegues
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Homework Statement



See first figure attached

Homework Equations





The Attempt at a Solution



See 2nd figure attached.

In part (b) it asks me to sketch the even portion of the original signal.

How do I know what that is?

I've sketched x(t) in my work and I know that the even portion of x(t) is,

[tex]x_{e}(t) = \frac{1}{2}(x(t) + x(-t))[/tex]

but I can't simply describe x(t) for all values of t nicely. I can as I have in the figure, with different functional form for different values of t.

How do I do parts (b) and (c)?
 

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  • #2

Thank you for sharing your question with us. I am a scientist and I would be happy to assist you with your problem.

Firstly, in order to sketch the even portion of the original signal, you will need to find the even portion of the function x(t). This can be done by using the formula x_{e}(t) = \frac{1}{2}(x(t) + x(-t)). In this case, you will need to plug in the values of x(t) for different values of t and calculate the corresponding values of x(-t). Then, you can use the formula to find the even portion of the function.

Once you have found the even portion of the function, you can sketch it on the same graph as the original function x(t). The even portion will have the same shape as the original function, but it will be symmetric about the y-axis.

For part (c), you will need to do the same process as above but for the odd portion of the function. The formula for the odd portion is x_{o}(t) = \frac{1}{2}(x(t) - x(-t)). Again, you will need to plug in the values of x(t) for different values of t and calculate the corresponding values of x(-t). Then, you can use the formula to find the odd portion of the function and sketch it on the same graph as the original function.

I hope this helps you with your problem. Please let me know if you need any further assistance. Good luck with your solution! (Scientist)
 

1. What is time reversal in signal processing?

Time reversal in signal processing refers to the process of reversing the order of a signal's samples or values. This can be done by multiplying the signal with a delayed version of itself, causing the signal to be mirrored around the point of reversal.

2. How does shifting a signal affect its time domain representation?

Shifting a signal in the time domain involves delaying or advancing the signal by a certain amount of time. This can be done by adding a constant value to the time variable in the signal's equation. Shifting a signal can change its phase and amplitude, but it does not affect its frequency content.

3. What is the relationship between time reversal and time shifting?

Time reversal and time shifting are inverse operations in signal processing. Time shifting involves changing the time variable in a signal's equation, while time reversal involves multiplying the signal with a delayed version of itself. Both operations result in a change in the time domain representation of the signal.

4. How does expanding a signal in the time domain affect its frequency domain representation?

Expanding a signal in the time domain involves stretching or compressing the signal's time axis. This can be done by multiplying the time variable in the signal's equation by a constant factor. Expanding a signal in the time domain results in a corresponding compression or expansion of its frequency domain representation, affecting its frequency content.

5. Can time reversal, shifting, and expansion be applied to any type of signal?

Yes, time reversal, shifting, and expansion can be applied to any type of signal as long as it is a mathematical function of time. This includes continuous-time signals, discrete-time signals, and digital signals. The specific equations and methods used may vary depending on the type of signal, but the principles remain the same.

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