low frequencies vs high frequencies

hello EDA members,

i m new to EDAboard n i start with a really silly question which i know is the basic of communication,

I want to know that from you people that why we need modulation other then reason for multiplexing,it's usually say that low frequency travels more then high irrespective of modulation schemes then y do'nt our speech frequencies travels more distance y we need a carrier frequency for it,plz explain me in detail.

thank u.

Yes, low frequencies travel much better than high frequencies! And if you did not mind having a 75 meter long antenna on your cell phone, you could operate it at 1 MHz.

:D :D :D :D

This is a funny answer

Of course it's true, but funny doesn't mean false (in my country) ! :D

Although energy is main reason, there is many of them like:

High freq. gives higher bandwidth (more data) for telecom. signals
Or more precise measuring if you dealing with radars.

And so on.

Design engineering is a pretty hard way of making a living! Nobody ever asks you to design something easy, or something you had done before! You NEED some humor every once in a while!

Reasons for using RF/Microwaves

Wider bandwidths due to higher frequency
Smaller component size leading to smaller systems
More available and less crowded frequency spectrum
Better resolution for radars due to smaller wavelengths
Lower interference due to lower signal crowding
Higher speed of operation
Higher antenna gain possible in a smaller space.

Disadvantages:

More expensive components
availability of lower power levels
Existence of higher signal losses.


In many RF/Microwave applications the advantages of a system operating at these frequencies outweigh the disadvantages.