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3.2.- THÉORIE - PRATIQUES FONDAMENTALES
In remote communications or Telecommunications, one of the main objectives is to transmit as much information as possible over long distances without interference or noise and using minimum resources.Voir plus
The Modulation Techniques allow the transmission of information simultaneously through the same communication channel and, therefore, a greater use of the media. Nowadays, the numerous modulation techniques available are grouped into two types: analog modulation and digital modulation. Within the analog modulations, depending on the parameter that contains the information to be transmitted, there is amplitude modulation (AM), frequency modulation (FM) and phase modulation (PM). Likewise, within the digital modulations, there is amplitude-shift keying (ASK), frequency-shift keying (FSK), phase-shift keying (PSK, DPSK, QPSK), and quadrature amplitude modulation (QAM).
The Antenna Theory is based on the study of the main characteristics of this type of devices, such as wavelength, gain, directivity, power, radiation pattern, standing wave ratio (SWR), etc. with the aim of transmitting and/or receiving signals that contain the information as efficiently as possible, that is, reaching the greatest possible distance with the minimum use of energy. Nowadays, there is a great diversity of antennas, each one for a different application. For example, monopole antennas, dipole antennas or loop antennas (square, circular, helical, etc.) are the most common ones in radio communications. The Yagi-Uda antennas are the most used ones in the reception of television signals. For communications by satellites or radars at frequencies in the microwave range, the most common one is the horn antenna with parabolic reflector excited by waveguides.Voir les produits