Basic signal analysis (system invertible)

  • Thread starter FrogPad
  • Start date
  • #1
FrogPad
810
0
Ok I have this really simple question that is bugging me.

Lets say you have the signal:

y(t) = x(t-4)

where y(t) corresponds to the output, and x(t) the input.

I know this system is invertible, but I don't really know how to show that this is the case. I see that the output is x(t) with an independet variable transformation such that the input shifted by 4 units to the right. So if we shift the output four units to the left then we get the input without the independent variable transformation. I just don't know how to express what is going on here mathematically.


Maybe I don't understand invertibility well enough to apply it.
From what I gather it can be shown by,

x(t) --> [system] --> y(t) = T{x(t)}
y(t) --> [invert] --> T{y(t)} = x(t)

I'm getting confused since the problem has x(t-4) in this case. I'm guessing I can show it with some type of function composition, but I need some help.

thanks
 

Answers and Replies

  • #2
marcusl
Science Advisor
Gold Member
2,797
456
You can make the substitution
t' = t - 4
so that
x(t') = y(t'+4)
The inverted function is non-causal, since you need to know future values of y to find the present value of x.
 

Suggested for: Basic signal analysis (system invertible)

  • Last Post
2
Replies
40
Views
2K
  • Last Post
Replies
2
Views
125
Replies
2
Views
362
Replies
2
Views
487
Replies
15
Views
560
  • Last Post
Replies
1
Views
313
Replies
1
Views
275
Replies
2
Views
1K
  • Last Post
Replies
13
Views
666
Replies
7
Views
460
Top