Telediffusion De France

France Telecom

Etat Francais

Telediffusion De France S.a.

Philippe Piole

Sébastien Palud

Pierre-Yves Jezequel

Jean-Yves Laurent

François Jacquin

Francois Jacquin

Laurent Prioul

Sebastien Palud

To broadcast synchronized radio waves in at least one frequency band in a predetermined territory, antennas (AS, ATI, AE) emit waves to respective coverage areas in which receivers (RQ, RB) measure characteristics of the emitted waves and transmit to a central server (SC) . The server analyzes the characteristics (CO) as a function of prediction models for broadcasting waves in the territory in order to determine adjustment parameters for the antennas. The server transmits the adjustment parameters to the antennas to control them in order to offer a greater diversity of radio broadcasting services and to optimize coverage areas according to different wave propagation modes.

System of transmit antennas adapted to propagation conditions for radio broadcasting

To avoid searching for a new location for very high hectometric wave antennas, an antenna according to the invention comprises an existing vertical structure having a height of at least approximately ten meters and including at least one electrically conductive element connected to the ground, and an excitation conductor wire () that is essentially electrically conductive, disposed at least in part in the vicinity of and outside the structure and connected to a emitter (E) so that the structure radiates substantially hectometric waves. The existing structure may be a broadcasting tower, a water tower, a chimney, a lighthouse or a lamp standard, wherein the excitation wire merges visually. The wire can be replaced by a conductive loop a few meters long, magnetically coupled to the structure.

Hectometric wave transmission antenna

An antenna comprises a quarter-wavelength skirt antenna adapted to be disposed over an artificial ground and comprising a vertical cylindrical tube closed at the upper end and a coaxial feed inside the tube. The radiation pattern of the skirt antenna is essentially omnidirectional with a low elevation angle. The skirt antenna is combined with a helical antenna disposed vertically above the skirt antenna and coaxially therewith. The surface closing the upper part of the tube of the skirt antenna constitutes a reflective plane for the helical antenna favoring a hybrid radiation mode specific to the latter, partially axial and partially radial, by lowering the receive lobe of the radiation pattern towards an elevation angle suitable for receiving signals transmitted via satellite. A coupling device combines the signals received by each of the two antennas and feeds them to a common coaxial line.

Composite antenna for receiving signals transmitted simultaneously via

Circuit for analyzing an amplitude-modulated electric signal. This circuit comprises a quartz oscillator operating at a frequency fq, a frequency transposer making it possible to transpose the spectrum of the incident signal about fq, a narrow filter centered on one of the side bands, a detector receiving said side band and the reference signal at frequency fq and two processing channels, one being an amplitude channel and the other a phase channel. Application of the measurement of the current in an antenna, to the characteristics of quadripoles, impedances, etc.

Analysis circuit for an amplitude-modulated electric signal comprising a

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Cesson-Sevigne, France

Philippe Piole