Timeline for Power and Energy Computations in the Frequency Domain
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Oct 27, 2020 at 14:35 | answer | added | user173292 | timeline score: 1 | |
| Oct 27, 2020 at 14:28 | comment | added | Formeanlegion | @Janka, thank you, that's exactly what I needed to know. I should be able to get the rest of the way on my own. | |
| Oct 27, 2020 at 14:27 | comment | added | Janka | Yes. And yes. If the spectrum does not change over time. And there is no "duration in the time domain". There's a duration. The time domain and the frequency domain are just different views on the same thing. The only thing you have to understand is the frequency domain is a model. It has limits. For example, you cannot model parts of a full wave with the fourier transform. So the duration has to be an integer multiple of the lowest frequency you model. | |
| Oct 27, 2020 at 14:24 | comment | added | Formeanlegion | @Janka, so, let's say I have a function with an area of A in the frequency domain. The power would be simply the area of that function? And then the energy would be taking that power and multiplying it by the duration of the signal in the time domain (if that duration were known)? | |
| Oct 27, 2020 at 14:20 | comment | added | Janka | Not in the time domain does not rule out time. If your spectrum changes over time, you have to add a third dimension — time — to your frequency domain calculations. Otherwise multiply the static power taken from the integration of the spectrum by the duration to get the energy. | |
| Oct 27, 2020 at 14:14 | comment | added | Formeanlegion | The form of Parseval's I'm familiar with requires access to the time domain of the function, which I have explicitly prohibited in my question. Since I can't access the time domain, I can't (as far as I know) use the integral to find the fourier coefficients. I don't know another method to find those coefficients. Edit: the comment I was replying to seems to have disappeared. | |
| Oct 27, 2020 at 14:12 | history | edited | Formeanlegion | CC BY-SA 4.0 |
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| Oct 27, 2020 at 14:09 | comment | added | Formeanlegion | It isn't homework. I've been trying to understand how to use frequency domain to find these values. Take, for example, Rayleigh's Property. It suggests the energy of a time domain signal equals the energy of a frequency domain signal when the absolute value squared of either is integrated over the domain (for which it is non-zero, at any rate). But it isn't immediately obvious if that's true, nor am I sure how to incorporate that into the definition for power, since power incorporates a factor of 1/2T into the definition. | |
| Oct 27, 2020 at 14:05 | comment | added | Andy aka | I think you need to show where you are stuck in this. It looks like homework so, how far did you get? | |
| Oct 27, 2020 at 14:02 | history | asked | Formeanlegion | CC BY-SA 4.0 |