some basic question about communication

cuz frequency is less sensitive to perturbations than amplitude.

what r the advantages of using high frequency carrier wave? Higher rate of transmission of information. cf shannon theorem.

Not sure what your question is. Bouncing on the ionosphere maybe ?

vic

Another reason is that transmitting a low frequency baseband signal with no modulation will need a large trasmission antenna in radio applications. By modulating the signal with a high frequency carrier u reduce the potential size of this antenna.

--Hage

Please tell us why adding modulation will affect antenna dimensions.

Also, please quote the material to which you are replying so other people can tell more about WTF.

Thanks

Don

will affect antenna dimensions.

you are replying so other people

to make sure i looked up in a book i had lying around:

"Modern Digital and Analog Communication systems" B.P.Lathi

p11.

"For efficient radiation of electromagnetic energy, the radiating antenna should be on the order of one-tenth or more of the wavelength of the signal radiated."

So say i send a signal with a frequency between 100 to 3KHz, your going to have a wavelength on the order of around 100 to 3000KM. So without modulation you would need a extremely large antenna. This is for radio applications.

Thanks, I had not looked at it quite like that.

Don

Smoke and mirrors.!

You'll find plenty of books on the subject.

Graham

high frequency carrier wave?