|
|
Post by johnpool on Oct 28, 2008 7:35:14 GMT -5
Hi there. I'm having problems understanding the concept of bandwidth. I'm not sure why it is different the bandwith of a baseband signal and that of a passband signal. And why do we do this distinction anyway? Aren't they both signals? I guess there must be a reason to distinguish a baseband signal from a passband signal. But what is it?
What is the bandwidth of a sinusoidal signal of X hz? What happens to this signal if I let it through a high-pass filter of X/2 hz?
Thanks in advance,
John
|
|
|
|
Post by charan langton on Oct 30, 2008 23:53:13 GMT -5
Bandwidth of a signal is its positive frequency. Baseband signals are defined as have frequency above 0. Voice is a baseband signal. Its frequency is about 30000 Hz. This is from 0 Hz to 30000 Hz. But if you draw its spectrum, you will see that it actually spans the same amount in the negative frequency. But we dont count that part, because bandwidth is always a POSITIVE quantity. We define it that way.
Passband is the frequency of the modulated carrier that is carrying the baseband signal. Now as the baseband signal which spanned the y-axis and had half its spectrum in the negative frequency, moves up to a new higher positive frequency and now all of its spectrum is in the positive realm. Now its bandwidth is twice because it has all translated to become positive.
Crazy, yes. but thats what it is.
Charan Langton
|
|
|
|
Post by rrrahul4u on Feb 4, 2009 5:06:41 GMT -5
Hi Eveyone ,
Plz tell me difference between wideband and narrowband transmission and when and why are they used?
|
|
|
|
Post by aya2002 on Feb 26, 2009 7:11:35 GMT -5
Hi charan langton
as i know the voice bandwidth is about 3.5 KHz and the audio is about 30 KHz is that correct?
|
|
