I am a bit confused.(adsbygoogle = window.adsbygoogle || []).push({});

http://pokit.org/get/bedc0ac7e1d17e01d7d58b021b81663c.jpg [Broken]

The function is y=x(2t)

and the point of it is to show the property of time-invariance.(which we should fail in this example, because it isn't time invariant.)

Input signal is x1(t)

Output signal is shown for that signal y1(t)

But when you shift it, x1(t-2) it doesn't give y1(t-2).

I am both ok and not ok with that.

First lets go over the math.

If I shift my signal x1(t) by -2

I get [itex] y_2(t)=x(2(t-2)) [/itex]

Is that correct?

But that is [itex] y_2(t)=x(2(t-2))=x(2t-4) [/itex] and that is original signal, shifted by 4, and then scaled by 2, which is not what it should be.

y2(0)=x(-4) which is 0, not 1.

I am probably stuck on something simple, but nevertheless I am stuck.

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# Signals and math confusion.

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