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Name: Ryan
Status: student
Grade: 9-12
Location: LA 
Country: N/A
Date: 7/29/2005


Question:
How does a radio transmitter work?


Replies:
This depends in part on what you mean by transmitter. Transmitter can refer to an entire radio set responsible for transmitting a signal, or just the particular bits of such a set that amplify the signal up to a high enough level to be detectable once radiated.

The first thing a transmitter needs is a carrier signal. this is the radio frequency it will transmit at. (Radio frequency, or RF, is an electrical variation in the thousands, millions, or even billions of times per second)

The next thing it needs is intelligence. (something we're actually trying to transmit, such as music or a voice) This is modulated onto the carrier frequency in one of two ways. Frequency Modulation (FM) is where the intelligence varies the frequency of the carrier signal. And Amplitude Modulation, (AM) where the transmitted strength is varied instead.

After these two signals are provided, a transmitter just has to amplify them. The exact amount varies, from a few watts for a cell phone, to millions of watts for high powered RADARs. The methods of amplifying usually include either transistors, (simple electronic components that increase power by acting like a gate on a larger power source), or Vacuum tubes (think "really fancy light bulbs") that accomplish the same thing as a transistor.

Ryan Belscamper



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