voice carrier frequency

[knockout_artist]

Good Day,
Can some one tell me any reading about structure of voice?

Things I need to know (in AM radio) amplitude madulation of voice
and also demodulation of it.
When we demodulate it do we use some carrier frequency to so people can hear that?

Thanks

[villampaxo]

As far as i know we use some carrier frequency because u = λf (u speed λ wavelength and f frequency) so we need a high frequency (small wavelength) carrier to transfer the wave. Also, the equation of the carrier is E = Ec(1 + msinwtm)sinwtc, tmod = modulated , tc = carrier, w = 2πf and m = Emax/Ec.

[berkeman]

I googled tutorial modulation AM, and got lots of hits. Here's a pretty good description of various AM demodulation techniques.

http://www.electronics-tutorials.com/receivers/am-radio-receivers.htm

Modulation is used for the transfer of information for a number of reasons. A couple of the most important are to be able to use radio frequency transfer (modulate to RF frequencies so that you can communicate wirelessly with antennas), and to be able to combine many channels of information into the same communication channel (like how there are many radio channels available in the AM or FM bands all at the same time).