# Thread: How does A wireless transmitter/reciever work???

1. And what kind of signal does it send??!!

Please, keep it simple as i am only 13!!!

2.

3. coils of wires with batteries create magnets

a transmitter is a magnet that keeps flipping direction

.....at a certain speed, that is the frequency

a radio simply detects that spinning electromagnet.....

4. A wireless transmitter / receiver send the electromagnetic signals which is a magnetic field that keeps on changing it's poles in a certain frequency and travels in space and even in vacuum.

6. Radio waves are radiation having both electric and magnetic fields, which is why it's called electromagnetic radiation. These fields oscillate/cycle (flip back and forth in polarity), and the number of times they do this per second is called its frequency. So, 100.0 MHz on your FM receiver means 100,000,000 oscillations per second.

There's a couple of basic ways to transmit/receive information: AM (amplitude modulation) and FM (frequency modulation).

AM (see first waveform in diagram below) is very basic where the strength (ie, amplitude) of the signal (ie, carrier wave) varies according to the amplitude of the sound waves being transmitted. So, think of plucking a guitar wire, and a mike picks up that sound energy, transfers it into electrical energy, and then uses it to modulate the amplitude of the carrier wave. Imagine the strength of, say, a 1,000 kHz signal (about the middle of the AM range in the US) whose strength, in effect, varies according to the position of the string. Of course, it will need a certain strength just to represent "zero" amplitude. Then the strength will increase when the string is to one side, and it will decrease when the string is to the other side.

FM (see second waveform in diagram below) is a little more sophisticated where the frequency of the signal (ie, carrier wave) varies according to the amplitude of the sound waves being transmitted.

Of course, there's special circuitry to produce AM and FM radio waves, and also to receive/decode these waves and transform them back into sound.

7. Thanks guys, that was really helpful!!!

8. Incase you did not get what a "field" is... Its like.. the light field(light rays from bulb) that you see from your eyes.. has a certain frequency in which electric and magnetic fields are moving perpendicular to each other and perpendicular to their direction of motion... the same applies to radio waves (or fields).. but these have a different frequencies.. hence you cant see them from your eyes..

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