História According to some authors, the technology of sound transmission by radio waves was developed by Italian Guglielmo Marconi in the late

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2 O que é a rádio? Radio is a feature of telecommunications technology used to provide communication through transcepção deinformações previously coded electromagnetic signal that propagates through space. A radio station is the system used to perform contact distance between two stations, it basically consists of a transceiver (transmitter-receiver) radio communications, a transmission line and the antenna itself. This system takes the name of the radiating system. Broadcasting is a commercial issue, which occurs only through the transmission of signals without their transcepção. Usually there are resources AM (only the important digital radio which is a gain for the stations that called modulation), FM is exclusive between them are much, stereo and RDS

Estrutura The radio is a system of communication through electromagnetic waves propagated in space, which are of different length are classified as high frequency short wave or long wave low

3 Estrutura The radio is a system of communication through electromagnetic waves propagated in space, which are of different length are classified as high frequency short wave or long wave low frequency, thus, used for various purposes such as television, radio, airplane, etc.. The normal radio communications systems are formed by two components: Transmitter - comprising a generator of oscillation, which converts the electrical current oscillations in a certain radio frequency, a transducer that converts information to be transmitted into electrical impulses corresponding to each value and a modulator that controls intensity variations in or oscillation frequency of the carrier wave, being conducted in low or high levels. When the amplitude of the carrier wave varies according to variations in the frequency and intensity of a signal, called AM modulation. However, when the frequency of the carrier wave varies within a set level at a rate equal to the frequency of a sound signal, called a modulation FM; Receiver - Its main components: the antenna to pick up electromagnetic waves and convert them into electrical oscillations; amplifiers that increase the intensity of these oscillations; demodulation equipment, a speaker to convert the pulses into sound waves and in most receivers oscillators to generate radiofrequency waves that can be mixed with the incoming waves.

História According to some authors, the technology of sound transmission by radio waves was developed by Italian Guglielmo Marconi in the late nineteenth century, but the U.S.

4 História According to some authors, the technology of sound transmission by radio waves was developed by Italian Guglielmo Marconi in the late nineteenth century, but the U.S. Supreme Court granted the Nikola Tesla merit the creation of radio, given that Marconi had used 19 Tesla's patents in its design. At the same time in 1893, in Brazil, Father Roberto Landell de Moura also sought similar results in experiments in Porto Alegre, in the neighborhood Mediatrix, where was his parish. He made the first radio broadcast in the world, and between the Mediatrix hill Santa Teresa. [citation needed] [edit] Early radioemissões The early history was marked by radio broadcasts, transcepção being used around the same time. Some consider the world's first radio broadcast was made in 1906, in the United States by Lee de Forest to experimentally test the triode valve. In Brazil, initially just might have military radios, the law was repealed by Francisco de Sá [1], and the first civil transmission was held on the centenary of the Independence of Brazil, on September 7, 1922, when President Pessoa, accompanied by the kings of Belgium, Albert I and Elisabeth, opened the Centennial Exposition of Independence in Rio de Janeiro. The opening speech of Pessoa was transmitted to receivers installed in Niterói, São Paulo and Petrópolis, through an antenna installed on Corcovado. On the same day, at night, the opera The Guarani, Carlos Gomes, the Teatro Municipal was transmitted to speakers installed in the exhibition, haunting the people present there. It was the beginning of the first radio station in Brazil: Radio Society of Rio de Janeiro. Founded by Edgar Roquette-Pinto, the station was donated to the government in 1936 and still exists today, but under the name of Radio MEC.

5 Tecnologia Receptor The function of the radio receiver is decoding the received electromagnetic signals from space, captured by the antenna, turning them into sound waves, digital signals and / or analog. Television and radio automotive, for example, are receptors. The equipment is connected to a receiving antenna, a system tuning and audio amplifiers, video and / or digital signals. Radio 1936 in Wood, AM and shortwave. Tower radio station. Transmitter The radio transmitter converts sound signals, analog or digital electromagnetic waves, sending them into space via a transmitting antenna, to be received by a radio receiver, for example, broadcasts AM, FM or TV Besides LW. Transceiver The radio transceiver, works both ways, as a transmitter and receiver, transceiver are some examples of the cell phone (mobile phone), the radars at airports, communication equipment in official vehicles, and private companies. Aside from broadcasting, there are other methods in use of equipment emitting radiofrequency influencing radio communications. Telegraphy, widely used until the mid-1970s. After the advent of digitization, transcepção via morse code fell into disuse commercially and militarily, although there are still users of telegraphy. Radiotelephony still used, but in other ways, for example, cell phones are radio modes. Radio station is not necessarily broadcasting or radio. A radio station can emit radio signals for various purposes, from military to industrial. Radio communication is the most widely used. Radiogoniometry is a form of radiolocation. A direction-finder locates a radio frequency emission of any kind. Radiolocation is a way of finding. A beacon, for example, one radioemissor, emits signals that are received by a direction-finder, which monodirectional having a system of reception, makes the triangulation of the station, locating it accurately. Radiotherapy for Diathermy called by some of the medical Shortwave. This system, although not in the radio issue, its relevance is therefore is a major interfering (Polluter) to radio communications. This is an equipment of high radio frequency transmitter power used in medicine and not in communication. Also not to be confused with Radiotherapy for Ionizing Radiation), this is done at the wavelength of x-rays. Its relevance is given to the radio because they are (along with diathermy equipment) big polluters of the electromagnetic spectrum. It is a medium that occupies a prominent place. Despite being a hobby, this is vital importance to the research and development of this science in various ways. The radio stations maintained by amateurs, lend themselves to informal conversations and communicated beyond the competitions and national and international competitions called contests. Besides the hobby, amateur radio services provide testing conditions for ionospheric propagation, direct, and reflection (including lunar) in various frequency spectrum. In extreme cases, the stations of radio amateurs, due to its portability, flexibility, range of use, power, and antenna systems for easy assembly and scope, assist Civil Defence authorities

6 worldwide in dangerous situations and disasters public.

Chapter-15. Communication systems -1 mark Questions

Chapter-15. Communication systems -1 mark Questions Chapter-15 Communication systems -1 mark Questions 1) What are the three main units of a Communication System? 2) What is meant by Bandwidth of transmission? 3) What is a transducer? Give an example. 4)