Importance

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Abstract

Methods and apparatus for transmitting electromagnetic radiation in a space for illumination and communication provide in that space a gas discharge lamp, a first antenna for emitting radio frequency signals and a second antenna for receiving such emitted radio frequency signals. The first antenna is located at a distance from the lamp which is larger than the distance between the first and second antennas. The lamp is energized with alternating current for emitting light in the mentioned space. Radio frequency signals are transmitted via the first and second antennas and the mentioned space having the gas discharge lamp provided and energized therein. The gas discharge in the lamp may be confined to a length shorter than one quarter of the shortest wavelength of the transmitted radio frequency signals. The gas discharge lamp may be mounted in a cross-polarized relationship to the first antenna. Additionally or alternatively, the gas discharge lamp may be shielded against radio frequency signals emitted by the first antenna. The gas discharge lamp may be energized by an alternating current having a frequency above the highest useful frequency of a signal modulated on a carrier in the radio frequency signal. The raido frequency signal may be frequency modulated, and may be demodulated by a frequency modulation receiver connected to the second antenna and having an amplitude modulation rejection for suppressing a disturbance caused by the energized gas discharge lamp in the transmitted radio frequency signal.

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First Claim