Research of the Response on the Pre-emphasis Circuits for LED Visible Light Communications
碩士 === 國立雲林科技大學 === 電子工程系 === 103 === Solid-state lighting is popular lamp and turn to art lamps, light communication and phototherapy and so on in the future. Due to the development of multimedia video services and cloud in recent years, the data transmission also is growing fast. The RF bandwidth...
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| Format: | Others |
| Language: | zh-TW |
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2015
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| Online Access: | http://ndltd.ncl.edu.tw/handle/58690278707508866807 |
| Summary: | 碩士 === 國立雲林科技大學 === 電子工程系 === 103 === Solid-state lighting is popular lamp and turn to art lamps, light communication and phototherapy and so on in the future. Due to the development of multimedia video services and cloud in recent years, the data transmission also is growing fast. The RF bandwidth is becoming not enough because of small bandwidth and restrictions on international regulations. So it cannot meet the demands of users. Visible light communication was proposed by Siemens of Germany in 2010, they suggested abandoning the crowded bandwidth in RF, instead of LEDs visible spectra with a high response speed on transmitted digital signal to replace the wireless communication system. Integration LEDs lamp enter into a communication system which it could be connected to wireless network anywhere.
This proposal of the research was to enhance the quality and increase the channel bandwidth of the visible light communication system. We would enhance the reaction time of LED with first order RC pre-adding circuit, and increase the communication transmission distance with lens which the LED signal transmitted in free space. RC circuit was attached behind of optical detection device could let the carrying capacity up to 1.6M Hz. The VPPM (Variable pulse position modulation) was added to the system to module the lighting and the brightness could be grown in linear.
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