Explain the Process about conversion of EM wave into Electrical Signals(DC)?

Question

Give Latest trends in EM transmission?

Answer 1

I am going to make the assumption that you are in school, and this is a home work question. EM waves are received by a properly tuned LC circuit. At the antenna side of this circuit, a diode, just a simple diode that needs about 0.3 to 0.4 volts to conduct, and a pulsating DC voltage is produced. This is the most simple of receivers, and has been around since the 1930's. Latest trends in EM transmission, go to your library and look up anything to do with any form of radio or laser communications.

Answer 2

The above covered it pretty well.  Will add my 2c anyway

Here's a flow diagram of a basic radio receiver  :

Antenna --> tuned circuit --> amplifier --> detector

EM waves causes voltage fluctuations in the antenna.  These voltage fluctuations are filtered by a tuned circuit (to select frequency) of these fluctuations.  Sometimes there is an amp before and after the tuned circuit.

The amplifier is to increase the signal amplitude so its easier to detect and do things with.  This can be a transistor or a module etc.

The detector is what converts the EM signal into a format where the data in the signal can be more readily accessed.  In amplitude modulated signals, this is typically a diode.  A diode only allows flow of current in one direction so the negative portion of the wave is clipped off.

You should now have a d.c. signal.