Jun 242009
In other words, why is it necessary to carry a message waveform onto a carrier wave of much larger frequency than that of the message?
Is it possible to configure a radio with only a microphone, power amplifier and antenna?
wavelenth = light speed / frequency
Thus, for human voice (whose frequency is around 3000Hz),
wavelength = 3*10^8 / 3000Hz=100000m = 100km
The antenna size should be really large.
If carrier frequency is 3*10^9, then the wavelength is 0.1 meter which is a feasible and reasonable antenna size.
Furthermore, how you can differentiate your local voice and far away voice?
