LED Modulation Characteristics in a Visible-Light  Communication System

Pei, Yanrong; Zhu, ShaoXin; Yang, Hua; Zhao, Lixia; Yi, Xiaoyan; Wang, Junxi Junxi; Li, Jinmin

doi:10.4236/opj.2013.32b034

Cited by 31 publications

(11 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Ещå îдíèм ñóщåñòâåííым фàêòîðîм, êîòîðыé âëèÿåò íà íåîдíîðîдíîñòь ñâåчåíèÿ мàññèâà ñâåòîдèîдîâ, мîжåò быòь мàêñèмàëьíàÿ чàñòîòà ïåðåêëючåíèÿ (ñðàбàòыâàíèÿ) ñâåòîдèîдîâ, êîòîðàÿ â èмïóëьñíîм ðåжèмå бóдåò îãðàíèчåíà âðåмåíåм íàðàñòàíèÿ è ñïàдà èмïóëьñà òîêà è, ñîîòâåòñòâåííî, ýëåêòðîëюмèíåñцåíцèè [7]. Мèíèмàëьíàÿ дëèòåëьíîñòь èмïóëьñà òîêà â ñîâðåмåííыõ СÄ-ýêðàíàõ, ïðèíцèï дåéñòâèÿ êîòîðыõ îñíîâàí íà шèðîòíî-èмïóëьñíîé мîдóëÿцèè, дîñòèãàåò 40 -60 íñ.…”

Section: îбсуждение результатовunclassified

“…Äëÿ ýòîãî быë èñïîëьзîâàí ãåíåðàòîð íàíîñåêóíдíыõ èмïóëьñîâ Г 5-48, ýëåêòðîëюмèíåñцåíцèÿ ðåãèñòðèðîâàëàñь êðåмíèåâым p-i-n-фîòîдèîдîм SFH 203 P è îñцèëëîãðàфîм Tektronix TDS 2022. Óñòàíîâëåíî, чòî фðîíò íàðàñòàíèÿ/ñïàдà èмïóëьñà ЭЛ In 0,2 Ga 0,8 N/GaN-ñòðóêòóð èññëåдóåмыõ RGB-СÄ ñîñòàâëÿåò 6-8 íñ, чòî ÿâëÿåòñÿ òèïèчíым дëÿ ñâåòîдèîдîâ íà îñíîâå íèòðèдà ãàëëèÿ [7]. Êàê âèдíî èз ðèñ.…”

Section: îбсуждение результатовunclassified

See 1 more Smart Citation

Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade

et al. 2017

View full text Add to dashboard Cite

The emission uniformity of LED chips in the entire range of brightness and colors is the problem in LED displays manufacture process. It was approved that at lowering brightness gradations appearing the radiation nonuniformity between LED chips, and the higher disorders will be seen on the lesser emission levels. The RGB LED chips, observed by us, were based on AlGaInP (red), In0.3Ga0.7N/GaN (green), and In0.2Ga0.8N/GaN (blue) and had nominal working current 20 mA. Analysis of the current-voltage characteristics and capacitance-voltage characteristics showed the presence of inhomogeneous semiconductor junctions and ohmic contacts in blue LEDs structures that are the source of possible irregularities in the final emission of LED displays. The variation of voltages (at current 10 mA) was 2.81—2.98 V for blue structures, and 1.9—2.0 V for red ones. Some of the blue structures had additional parasite current-flow mechanism at low current. Rise time and fall time of electroluminescence pulse of blue structures were measured. The shortest LED pulse time in LED displays is limited by duration of 6—8 ns. The quality of LED displays may be improved by implementing the preliminary control of LED chips in a narrower range of voltage variation at operating currents, or more narrow interval of I—V variation. This additional LEDs sorting will of course reduce the percentage of the total amount of light-emitting diodes, but may improve the image (video, photo) quality at translations by using a lower brightness gradations.

show abstract

Section: îбсуждение результатовunclassified

Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In the experiment, we have changed the bias current of the transmitter LED as well as the reverse voltage of the receiving LED. A greater bias current increases the modulation bandwidth of the LED [8], but a bias too high may result in nonlinear behavior and increased energy consumption. In both LEDs (red and amber) the bias currents were 7.5 mA, 15 mA, 22.5 mA, and the modulation index (MI) was 15 %, calculated according to the definition…”

Section: The Experimental Setupmentioning

confidence: 99%

Transmission Beyond 100 Mbit/s Using LED Both as a Transmitter and Receiver

Stępniak¹,

Kowalczyk²,

Maksymiuk³

et al. 2015

IEEE Photon. Technol. Lett.

View full text Add to dashboard Cite

In the paper, experimental operation of a wireless transmission link employing identical LEDs both as transmitter and receiver is demonstrated. The transmitted signal is a simple, two-level pulse amplitude modulation. Digital equalization at the receiver is applied to overcome the bandwidth limitation of the link. Transmission throughput exceeding 100 Mbit/s is reported, even if the receiving red LED operates in the photovoltaic mode.

show abstract

“…The 3 dB modulation bandwidth of an LED can be defined as the range of frequencies used to modulate the drive current for which the detected optical power drops by 3 dB, with respect to the optical power emitted with DC drive current. It is found that LEDs can theoretically have a 3 dB bandwidth of up to 2 GHz [13,14]. Additionally, an LED with an optical modulation bandwidth of 1.7 GHz has also been proposed [15].…”

Section: Introductionmentioning

confidence: 99%

2 Gbit/s VLC Scheme Using Time-Frequency Color-Clustered MIMO Based on BCYR LEDs

Han

Sewaiwar

Chung

2016

Journal of the Optical Society of Korea

View full text Add to dashboard Cite

A 2 Gbit/s visible-light communication (VLC) scheme using time-frequency color-clustered (TFCC) multiple-input multiple-output (MIMO) based on blue, cyan, yellow, and red (BCYR) light-emitting diodes (LEDs) is presented. In the proposed scheme, BCYR LEDs are employed to form four different color clusters. Data transmission using the four color clusters is performed in MIMO, so that the scheme achieves a very high speed of data transmission. Moreover, the scheme employs the TFCC strategy to yield high performance in terms of bit error rate (BER). TFCC operates in such a way that the original data and the two delayed versions of the data are multiplied by orthogonal frequencies and then transmitted using a specific color of the BCYR LED. In the receiver, color filters are employed to detect the data transmitted from the desired cluster. Selection combining (SC) is also performed to yield a diversity effect within each color cluster, to further improve the performance. Performance evaluation demonstrates that the proposed TFCC MIMO VLC offers a data rate of 2 Gbit/s and a bit error rate of 4×10 , at an Eb/No value of merely 3 dB.

show abstract

LED Modulation Characteristics in a Visible-Light Communication System

Cited by 31 publications

References 4 publications

Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade

Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade

Transmission Beyond 100 Mbit/s Using LED Both as a Transmitter and Receiver

2 Gbit/s VLC Scheme Using Time-Frequency Color-Clustered MIMO Based on BCYR LEDs

Contact Info

Product

Resources

About