signals and systems analyse

[Bhuvanesh Nick]

what is toime domain and frequency domain means?

 

[albbg]

In simple words:
Given a signal I can see it as an evolution of, for instance, voltages with respect to the time. This happens when I analyze the signal using an oscilloscope. Means how the signal changes instant by instant. This is the time domain.
But if I take a picture of the same signal, I frooze it and I analyze its frequency content I'm analyzing the signal in the frequency domain. In this case I can see for every frequency of the span I'm considering, the levl of that signal. Frequency f1 will have level V1, frequency f2 level V2 ans so on . I can, as in a film, freezing the signal instant by instant and to each "frame" apply the frequency analysis so I can see how the frequency (spectral) content of the signal evolve with time.

 

[Bhuvanesh Nick]

thank you sir..can u telll me some more depth of frequency domain..plzz sir

 

[johanan]

Hey,
This is nothing. Don't be so tensed by it. Its really simple. See every sound you hear is a combination of many frequencies. We are talking about audio signal here. Im using an audio signal because you listen to music all the time and you can easily relate to it.
So you see. Every sound has a lot of frequencies combined to form that sound. All the frequencies add up. Imagine that as many sine waves with many frequencies all adding up (How they add up requires graphical explanation, so assume they add up and form a new signal). But each of these sine waves has different amplitudes. A frequency domain plot will let you know which frequencies form the signal and which frequencies have higher amplitudes compared to others. People usually go for a transform, such as a fourier transform to convert a time domain signal to a frequency domain signal to see what all frequencies make up that signal and in what proportion. Different sounds will be made up of different frequencies in different proportions (meaning amplitude). I hope you are still with me. I hope you understand upto this.

With that said. Ill give you examples to clarify. If you listen to a Bass drum. It will have low frequencies with higher amplitudes. It will not much have very high frequencies it will have mid range frequencies with low amplitude.
If you take a Violin for example, it will have high frequencies and mid frequencies and not the low frequencies.

If you have doubts ask me

JJ

 

[Bhuvanesh Nick]

Hey,
This is nothing. Don't be so tensed by it. Its really simple. See every sound you hear is a combination of many frequencies. We are talking about audio signal here. Im using an audio signal because you listen to music all the time and you can easily relate to it.
So you see. Every sound has a lot of frequencies combined to form that sound. All the frequencies add up. Imagine that as many sine waves with many frequencies all adding up (How they add up requires graphical explanation, so assume they add up and form a new signal). But each of these sine waves has different amplitudes. A frequency domain plot will let you know which frequencies form the signal and which frequencies have higher amplitudes compared to others. People usually go for a transform, such as a fourier transform to convert a time domain signal to a frequency domain signal to see what all frequencies make up that signal and in what proportion. Different sounds will be made up of different frequencies in different proportions (meaning amplitude). I hope you are still with me. I hope you understand upto this.

With that said. Ill give you examples to clarify. If you listen to a Bass drum. It will have low frequencies with higher amplitudes. It will not much have very high frequencies it will have mid range frequencies with low amplitude.
If you take a Violin for example, it will have high frequencies and mid frequencies and not the low frequencies.

If you have doubts ask me

JJ

thank you so much sir
its really helpfull
thank u again