some basic question about communication

[prad]

why do we go for modulation?what r the advantages of using high
frequency carrier wave?
how does a high frequency wave travel large distance?

 

[vic]

why do we go for modulation?

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.

how does a high frequency wave travel large distance?

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

vic

 

[Hage-bai]

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

--Hag

 

[Don Bowey]

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

 

[Hage-bai]

why do we go for modulation

Please tell us why adding modulation will affect antenn dimensions

Also, please quote the material to which you are replying so othe peopl
can tell more about WTF

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

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

p11

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

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

 

[John Fields]

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.

 

[Don Bowey]

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

 

[Jamie]

why do we go for modulation?what r the advantages of using high
frequency carrier wave?
how does a high frequency wave travel large distance?

Smoke and mirrors.!

 

[Pooh Bear]

why do we go for modulation?what r the advantages of using high
frequency carrier wave?
how does a high frequency wave travel large distance?

You'll find plenty of books on the subject.

Graham

 

[ruth]

why do we go for modulation?what is its need?what r the advantages of using high frequency carrier wave?
how does a high frequency wave travel large distance?