Energy and Power Signals
ฝัง
- เผยแพร่เมื่อ 15 ก.ย. 2010
- An introduction to energy and power signals
This video is one in a series of videos being created to support EGR 433:Transforms & Systems Modeling at Arizona State University. Links to the other videos can be found at sites.google.com/a/asu.edu/sig...
Just RESPECT! You are the best professor I have ever "seen" (along with the Khan Academy). You explain every single equation and make it seem so simple. This is where professors usually fail, they are lost inside the math equations and they don't explain the actual meaning of those graphically.
Please keep up this good work and thank you for all these amazing videos!
thank you so much sir. Love these video. Helps me understand Energy signal. Love from Malaysia.
It took me a long time to understand it... it is important to understand the diffrence what Power and Energie is. Also great Work and the end summary was very Great.
Thank u very much. I am watching your videos relating to signals and systems. Nice work sir...
That is really Great! Thanks for posting these videos!
Explained really well!Thanks!
@teene0 The power spectral density is a function of frequency that shows how much power is at each frequency. The power in this lecture can be obtained by integrating the power spectral density over all frequencies.
Important note @ 4:15
You, the reader, may wonder where is the proportionally constant for the expression |x(t)|^2. You may also wonder what would be definition of a power signal if we instead had a capacitor or inductor. Both questions are answered when I tell you the following fact: *power signals are **_defined_** for a resistor of 1 Ω.*
Because of this, now the expression for power signal is the following: if x(t) is a voltage, then the expression is |x(t)|^(2)/R = |x(t)|^(2)/(1 Ω) = |x(t)|^2 [W]; if x(t) is a current, then the expression is |x(t)|^(2)·R = |x(t)|^(2)·(1 Ω) = |x(t)|^2 [W]. These are the same results in the video, and is the reason why the expression for a power signal is |x(t)|^2. Remember, the reason is because *such power is defined for a resistor, of 1 Ω,* not for a resistor of other value, nor for a capacitor or inductor or a voltage or current source.
Thank you!
Sometimes we can gain more information from one comment than from a total book combined. Thank you so much:)
You triggered many OCDs at 8:40 by leaving the yellow piece of line in there...
@NaqashHaider You find the energy of a discrete signal by summing rather than integrating. Square each signal value and then sum them to find the signal energy.
Thanks for the video, it helped me a lot!
nice explanation, a lot of thanks to you dude
Thank you for sharing your knowledge :-)
great video !
Thank you very much sir . . .
Thank you so much!
Thank you very much!! :D
Thank you Sir 😃
great video
Good explanation
thanks for the help
Thanks a lot!
''The power in this lecture can be obtained by integrating the power spectral density over all frequencies.''
Parseval's theorem
Plz increase the power of your volume!!! Though it was a nice lecture :)
awesome mate. hours of head scratching solved in 13 minutes. stupid books!
what is the need of limit T->infinity. in case of periodic signals like cos(x) whatever time period we take the result is going to be the same.
thx mate
wooow thhhhanks so much
I have trouble understanding a problem. I need to find the Einfinity of y(t)=integral(x(Tau)dTau) from -infinity to t where x(t)=delta(t+2)-delta(t-2). I understand what x(t) is and I understand how the energy is supposed to be calculated. However I don't understand the y(t). I know that if you integrate delta(Tau) dTau from -infinity to t you get step function(t). However how do you integrate x(Tau-t0) from -infinity to t (where t0 is a constant) and why?
u(n)-u(n-k) is energy signal or not?thanks in advance
How i am gonna find the energy of discrete signal.......
can i still use integration?????
can any1 answer this dumb question?????
why x(t) ^2 is generalized for all signals to calculate energy?
does that mean ,output is linearly proportional to x(t) ??
lol
thank you for your video
is your channel mainly electrical engineering. i dnt know how to work with this new youtube layout
Super sie
why do we need the limit as T goes to infinity, as opposed to just over one period T?
In the case of a periodic signal, over one period is sufficient. But in the video he wants to be more general to include even non periodic signal (e.g. random signal).
Mathieu Boutin I see. Thanks!
I understand what you're saying, but it still doesn't make sense.
You're talking about POWER, the change of rate of energy with respect to time. Or the amount of work done per unit of time. So to find an expression for power, the UNITS must be so that J/t, or whatever units of time.
So what would happen if I were to analyze an analog signal that represents the waves of the ocean? The units of it would be displacement vs time (or displacement vs displacement). So if I were to integrate this, I would end up with units displacement x time, which has nothing to do with energy or power.
So what is "signal power" really, anyway? It clearly doesn't mean real power as defined in physics. What is the meaning of the measurement made from the equation?
analog signal that represent waves of the ocean is pretty vague. if you're talking about a system that measures tides, a change in the amplitude of a wave would correspond to a change in the sytem which would be an electrical signal.
we cant just measure waves of the ocean. we need a system.
Hallo an alle HSRM Studenten!
1.5x is recommanded
Why is the average power of a finite energy signal equal to zero?
is it because of 1/T ?
Anupma Garg It's because the average is calculated over an infinite period of time, but the energy signal only exists for a finite period. So there is an infinite period of time where the power is zero, and however much power exists during the finite period is utterly insignificant by comparison.
Ty man
@@charlesfinley3234omg, from where did u get this information? and whyyyyyyyyyy the FuCk no one explained it in the videos?
5:05 ı didnt unserstand logic of square of x(t)
X is basically voltage or current of the circuit..... Power is directly proportional to square of energy source i.e x🤗
Hm, power signals should be called average power signals.
pls be loud-- i can not hear u
i can not hear u sir -- pls be loud
sorry but that was so boring. thank you for your effort though
great video