Trace a radio broadcast from the radio station transmitter to your ear?

Answer 1

Power from the final power amplifier stage of the transmitter ==> out the transmission line ==>

either up the tower to the antenna, or to the base of the tower when the tower is the antenna.

Then from the antenna out into space, in the form of electromagnetic radiation.

A tiny, infinitesimal fraction of the energy is intercepted by my antenna, where it induces a small

RF current. The current flows down my transmission line, through a coil in my radio, to ground.

On its way down toward ground, I use the RF current to control an amplifier stage in the front end

of my radio, where a copy of the signal is created at a much higher power level ... something that's

loud enough for the rest of the radio to work with.

The copy is combined with a local oscillator in a non-linear stage, where all of the sum-and-difference

frequencies among the local oscillator frequency, the radio station's carrier and sideband frequencies

are generated.

The narrow bundle of frequencies centered at the radio's preferred IF frequency is selected to

survive, and everything else is flushed to ground. The preferred IF frequency was created by

carefully controlling the frequency of that local oscillator in the last paragraph.

The IF bundle is amplified a few times, then it's ready for "detection". It's passed through another

non-linear stage where sums and differences of frequencies are generated, but this time, there is

no local oscillator. The sums and differences are just the mixtures of the various frequencies

present in the IF bundle. One of those products is the (carrier frequency) minus the (sideband

frequency) ... which is just a copy of the announcer's voice. This mix-product is selected to survive,

and all the rest are again flushed to ground.

Now the audio is amplified a couple of times, and it's finally ready for the ear-buds or the loudspeaker.

Answer 2

It is electromagnetic energy that converts into sound energy. Many people confuse electrical and electromagnetic.

Answer 3

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