What is Bandwidth and Why is 3 dB Important?

[snshusat161]

please explain it in easy language. explain other terms (like freq. spectrum) if u'll use. nd y there is always 3 db shown in its diagram.

 

[sophiecentaur]

In general terms it describes the frequency interval in which most (or, sometimes, a defined proportion) of the energy of a signal is transmitted.
For a straightforward sort of signal, if you plot the spectrum, then the bandwidth is often quoted as the interval between the frequencies where the average spectral level is half the maximum level. That is 'between the 3dB points'.
You can only talk usefully in these terms for signal with a spectrum that is 'single humped'. It needs to be more tightly specified to be of use when describing other types of signal.

 

[snshusat161]

totally confused! so much of technical language. please tell what is frequency spectrum. use everyday language. no matter if the definition is not so precise.

 

[zgozvrm]

It's kind of like a garden hose; the bigger it is, the more water (or in this case, data), it can transfer at a given speed.

 

[sophiecentaur]

I think it might be best to read the Wikipedia pages on the terms you don't know. As I don't know what you don't know, I really don't know how to start to answer your original, very general, question.
You are expecting a lot if you want to understand about something that comes half way through studies on oscillations and waves and don't have the basics. Wikipedia doesn't usually insist on a lot of prior knowledge in it's treatment of basic terms.
Many 'easy to ask' questions don't have three word answers.

 

[sophiecentaur]

It's kind of like a garden hose; the bigger it is, the more water (or in this case, data), it can transfer at a given speed.

I have to admit; that is a very good start!