The document discusses the definition, principles, contents, and conclusion about radio. It defines radio as the transmission of electromagnetic signals below the visible light spectrum, through free space. The principles section explains how sound and music are transmitted from a station through changing the amplitude of propagating signals, which are then converted back to sound through speakers. The contents section lists different types of radio programs like news, music, variety, and funny programs. The conclusion states that radio continues to evolve through various content to communicate with people, and radio frequencies ensure it will not be eliminated.

1. About the Radio
20082454 Taekkyun Nam

2. Contents
- Definition
- Principles
- Contents
- Conclusion

3. Definition
Radio is the transmission of signals through free space by
electromagnetic waves with frequencies significantly below
visible light, in the radio frequency range.
Etymology
Signals propagate through the dialogue and music such as
voice broadcasting for a number of unspecified way.
Oldest long broadcast medium wave amplitude modulation by
basic approach has not changed in 100 years, a few ways,
but still radio mainstream. This way, and "AM broadcast"
receiver typically referred to as "AM Radio". "FM broadcast"
also due to the frequency modulation microwave radio broadcast
and listen widely referred to as "FM radio".

4. Principles
The principle of radio sending voice load
on the amplitude of the propagating far.
Turned into propagated sounds or music from the station
to the transmitting antenna sends.
Back propagation change
the sound of music sounds through the speakers.

5. Contents
Current event Program Music Program
Passed Vivid and in-depth news recently To hear the music and to introduce the program.
Variety Program Funny Program
Eloquent and witty story introduces fun. Gives a laugh with a funny story.

6. Conclusion
Radio continues to evolve.
Communicating with people through a variety of content.
A radio frequency will not disappear. So radio will not be eliminated

7. Source
http://en.wikipedia.org/wiki/Radio
The first radio broadcast in the United States in 1920 was conducted
http://blog.naver.com/coolsea?Redirect=Log&logNo=40015708404
http://radio.sbs.co.kr/cultwoshow/
http://www.imbc.com/broad/radio/fm/look/
http://www.imbc.com/broad/radio/fm/enjoy/index.html
http://www.imbc.com/broad/radio/fm4u/musiccity/index.html