What happens inside a CD player?
An infrared laser is focused onto the metallic reflective layer of the disc, where a spiral track of “pits” and “lands” represents the zeros and ones of digital signals. The return signal is converted by a photodiode sensor into a digital electric signal, which is converted to analog form for reproduction of the original recorded sound. Optical recording, introduced by the Sony Corporation and Philips Electronics NV in 1982, allows accurate reproduction of sound over virtually the entire range of human hearing.
Encyclopædia Britannica, Inc.
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Contunico © ZDF Studios GmbH, Mainz; Thumbnail © Neeraj Charurvedi/Dreamstime.comLearn about India's efforts to improve its education system, 2009 film.
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© American Chemical Society (A Britannica Publishing Partner)New laser-based technique to check the structural integrity of airplanes, ships or bridges, without having to dismantle them or remove any material for testing in order to reveal hidden damage in their metals.
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© American Chemical Society (A Britannica Publishing Partner)The development of screen-printable electronic ink for flexible electronics.
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Encyclopædia Britannica, Inc.The laser scanning method employed in compact disc players
An infrared laser is focused onto the metallic reflective layer of the disc, where a spiral track of “pits” and “lands” represents the zeros and ones of digital signals. The return signal is converted by a photodiode sensor into a digital electric signal, which is converted to analog form for reproduction of the original recorded sound. Optical recording, introduced by Sony Corporation and Philips Electronics N.V. in 1982, allows accurate reproduction of sound over virtually the entire range of human hearing.
