Based on the author's PhD thesis, this book is a theoretical study of subterranean radio communication, with the focus on methods that depend primarily on the penetration of electromagnetic fields... More > through the ground. Through-the-earth communication using e-m fields - specifically magnetic induction - plays a role in search and rescue systems used in the mining industry. It is also used for borehole telemetry, pipeline location and by cavers and pot-holers. Chapters describe propagation, antennas, and the design of transmitters and receivers. A figure of merit - the specific aperture - is introduced as an aid to antenna design. A crucial aspect of all systems is the signal to noise ratio, for which the strategy of noise-matching is introduced. The design of a wide-band low-frequency sounder is described, for channel evaluation using a non-ideal binary sequence. A method of calculating the inverse of a generalised sequence is described, for which cross-correlation results in a system identification signal.< Less
Based on the author's PhD thesis, this book is a theoretical study of subterranean radio communication, with the focus on methods that depend primarily on the penetration of electromagnetic fields... More > through the ground. Through-the-earth communication using e-m fields - specifically magnetic induction - plays a role in search and rescue systems used in the mining industry. It is also used for borehole telemetry, pipeline location and by cavers and pot-holers. Chapters describe propagation, antennas, and the design of transmitters and receivers. A figure of merit - the specific aperture - is introduced as an aid to antenna design. A crucial aspect of all systems is the signal to noise ratio, for which the strategy of noise-matching is introduced. The design of a wide-band low-frequency sounder is described, for channel evaluation using a non-ideal binary sequence. A method of calculating the inverse of a generalised sequence is described, for which cross-correlation results in a system identification signal.< Less
The purpose of this work is the development of an electronic system for the
noise monitoring, ideal for enviroments like libraries and hospitals, where a
work or rest atmosphere is requested, free of... More > this disturbance type. < Less
(2º EDITION B&W) The purpose of this work is the development of an electronic system for the
noise monitoring, ideal for enviroments like libraries and hospitals, where a
work or rest... More > atmosphere is requested, free of this disturbance type.< Less
The purpose of this work is the development of an electronic system for the
noise monitoring, ideal for enviroments like libraries and hospitals, where a
work or rest atmosphere is requested, free of... More > this disturbance type.< Less
(2º EDITION B&W) The purpose of this work is the development of an electronic system for the
noise monitoring, ideal for enviroments like libraries and hospitals, where a
work or rest... More > atmosphere is requested, free of this disturbance type.< Less
Futuristic architectures, smoky urban atmospheres, neon lights, images from one of the most sophisticated Asian metropolis.
The photographer shows the portrait of a labyrinthine city, exotic and... More > mysterious which overnight shows its hidden sides through fascinating play of light and shadows.
Each image is accompanied by a back noise, the sound of a metropolis that has temporary slowed his race, the padded sound of a development that seems unstoppable even in the darkness of the night.
The fantastic contemporary architecture of Shanghai show the face of a constantly changing megalopolis. The Shanghai's night hide anxieties and hopes of a nation that is going through an important moment in its history.
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Click the button besides for a low resolution preview.
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More Info about the Photographer Alessandro Piras at www.pirasphoto.com< Less
