What is the energy and power os signal mean in real...??

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koolguy

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Hi,

After studying so many topics in subject..
I am not aware of energy of signal and its power does mean ,what??
please tell me....
 
Alright, I have studied the formula of Power and Energy for a signal.....but i don't understand it in real world.
let us suppose a sin wave in this it have amplitude, freq. but if we tak about Energy and power of it what does it mean?? and how??
 
If we're going to discuss things like "power" and "energy", we need to agree on what they mean, wouldn't you say?

My engineering textbook provides the following explanations/definitions:


So we see that energy is an instantaneous value, and power is a rate (it is time-related). Does this make sense?

Now, can you see how this relates to electrical circuits?
 
The energy of a sine-wave is measured by its power, which is energy transfered per unit time. The power is independent of frequency and is determined by the voltage and current of the sine-wave. The instantaneous voltage (in volts) times the instantaneous current (in amperes) gives the instantaneous power (in watts). The RMS heating power of a sine-wave averaged over one cycle is 0.5 times the peak voltage times the peak current if the current and voltage are in phase as when driving a purely resistive load.
 
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Now i am able to understand power and energy of signal...
if we talk about the Fourier transform from basic application, what is the use of it as it change freq. domain to time domain vice versa..
please explain it with some real( practically) signal explanation!!
 
RITESH KAKKAR said:
if we talk about the Fourier transform from basic application, what is the use of it as it change freq. domain to time domain vice versa
Click to expand...

One thing the Fourier transform is very useful for is extracting the relative strength of a signal's harmonics (going from the time to the frequency domain). An audio signal, for example, when run through a spectrum analyzer, results in a display of the harmonics and their strength relative to the fundamental frequency. This is how distortion measurements (like THD%) are made.
 

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When the distorted sin wave is converted into freq. domain the amplitude reaches above 400 ( what that's??) and how freq is calculated of that sample signal...as F=1/t.
If we talk about the the second image, the harmonics at 60hz is called h=1, then freq. at 180 is called 3....that mean as freq. increase the harmonic no. increase.
 
Not sure what you're asking (you really need to learn decent English!).

Concerning harmonics, you have the general idea: the first harmonic is the fundamental (F1), the original frequency. The second harmonic is twice that, the third is three times that, etc. Notice that that illustration only showed odd harmonics (F3/5/7 ...). Probably the result of measuring a push-pull output stage, which doesn't generate any even-order harmonics (F2/4/6 ...).
 
Probably the result of measuring a push-pull output stage
Click to expand...
how harmonic is relayed to push-pull stages....??

In first fig. the Sin wave of time domain is converted into freq. domain (the parameter like amplitude and freq. how they are calculated??)
 
RITESH KAKKAR said:
how harmonic is relayed to push-pull stages....??
Click to expand...

Because of its balanced configuration (two amplifying devices, each amplifying half of each cycle), a push-pull amplifier typically has zero (or close to zero) even-order harmonics in its output, since these tend to be cancelled by the output stage.

In first fig. the Sin wave of time domain is converted into freq. domain (the parameter like amplitude and freq. how they are calculated??)
Click to expand...

Forget amplitude: that's not important here.

Frequency is the number of complete cycles (positive + negative) per second.

Is that what you mean? Concerning how they're calculated, well, that's a function of the Fourier tfransform. Unfortunately, I can't tell you how that works (since I don't know). Perhaps someone else can explain.
 
If we talk about digital filters and analog filter ( like Low pass RC filter).
IIR is digital filter, what the basic diff. both of them?? and why digital signal are not passed through analog filters.
 
RITESH KAKKAR said:
If we talk about digital filters and analog filter ( like Low pass RC filter).
IIR is digital filter, what the basic diff. both of them?? and why digital signal are not passed through analog filters.
Click to expand...

IIR? As in infinite impulse response? Sorry, you're going waaaaay over my head here. Someone else will have to take this up.
 
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