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Radio is the transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. Information is carried by systematically changing (modulating) some property of the radiated waves, such as amplitude, frequency, or phase. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information. Originally, radio or radiotelegraphy was called "wireless telegraphy", which was shortened to "wireless". The prefix radio- in the sense of wireless transmission, was first recorded in the word radioconductor, coined by the French physicist Edouard Branly in 1897 and based on the verb to radiate (in Latin "radius" means "spoke of a wheel, beam of light, ray"). "Radio" as a noun is said to have been coined by advertising expert Waldo Warren (White 1944). The word appears in a 1907 article by Lee de Forest, was adopted by the United States Navy in 1912 and became common by the time of the first commercial broadcasts in the United States in the 1920s. (The noun "broadcasting" itself came from an agricultural term, meaning "scattering seeds".) The term was then adopted by other languages in Europe and Asia, although British Commonwealth countries continued to use the term "wireless" until the mid-20th century. In recent years the term "wireless" has gained renewed popularity through the rapid growth of short-range computer networking, e.g., Wireless Local Area Network (WLAN), WiFi and Bluetooth, as well as mobile telephony, e.g., GSM and UMTS. Today, the term "radio" often refers to the actual transceiver device or chip, whereas "wireless" refers to the system and/or method used for radio communication, hence one talks about radio transceivers and Radio Frequency Identification (RFID), but about wireless devices and wireless sensor networks. Radio systems used for communications will have the following elements. With more than 100 years of development, each process is implemented by a wide range of methods, specialized for different communications purposes.
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Radio Articles
The Advantages of Internet Radio Advertising
by Melvin Richardson
Oct 16, 2008
Everyone is taking note of the economy and right now it has everyone on their heels playing defense, especially the small business owners. A lot of business owners and corporations as well have stopped their marketing and advertising efforts altoget...
Business Development using the C.E.O. Plan
by Melody Campbell
Mar 24, 2008
If you have a product, and have researched your market, this one simple three step process will ensure your success. If you take all the business guru's and condense their message to the simplist possible formula, I'm confident they would all agre...
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