Radio is the technology of using radio waves to carry information, such as sound, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.[n 1] When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.
Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and radio waves into an electric current. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual frequencies to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form that is usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc. Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.
A radio communication system requires a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.
The term “radio” is derived from the Latin word “radius”, meaning “spoke of a wheel, beam of light, ray”. It was first applied to communications in 1881 when, at the suggestion of French scientist Ernest Mercadier, Alexander Graham Bell adopted “radiophone” (meaning “radiated sound”) as an alternate name for his photophone optical transmission system. This is all about radio.
Samsung (Hangul: 삼성; Hanja: 三星; Korean pronunciation: [samsʌŋ]) is a South Korean multinational conglomerate headquartered in Samsung Town, Seoul.It comprises numerous affiliated businesses, most of them united under the Samsung brand, and is the largest South Korean chaebol (business conglomerate).
Samsung was founded by Lee Byung-chul in 1938 as a trading company. Over the next three decades, the group diversified into areas including food processing, textiles, insurance, securities and retail. Samsung entered the electronics industry in the late 1960s and the construction and shipbuilding industries in the mid-1970s; these areas would drive its subsequent growth. Following Lee’s death in 1987, Samsung was separated into four business groups – Samsung Group, Shinsegae Group, CJ Group and Hansol Group. Since 1990, Samsung has increasingly globalised its activities and electronics; in particular, its mobile phones and semiconductors have become its most important source of income. As of 2017, Samsung has the 6th highest global brand value.
Notable Samsung industrial affiliates include Samsung Electronics (the world’s largest information technology company, consumer electronics maker and chipmaker measured by 2017 revenues), Samsung Heavy Industries (the world’s 2nd largest shipbuilder measured by 2010 revenues), and Samsung Engineering and Samsung C&T (respectively the world’s 13th and 36th largest construction companies). Other notable subsidiaries include Samsung Life Insurance (the world’s 14th largest life insurance company), Samsung Everland (operator of Everland Resort, the oldest theme park in South Korea) and Cheil Worldwide (the world’s 15th largest advertising agency measured by 2012 revenues).
Samsung has a powerful influence on South Korea’s economic development, politics, media and culture and has been a major driving force behind the “Miracle on the Han River“. Its affiliate companies produce around a fifth of South Korea’s total exports. Samsung’s revenue was equal to 17% of South Korea’s $1,082 billion GDP.