12 results on '"Arulandu A"'
Search Results
2. Modeling and analysis of transmitter performance in visible light communications
- Author
-
Yan Wu, Kumar Arulandu, Guofu Zhou, Xiong Deng, Jean-Paul M. G. Linnartz, Shokoufeh Mardanikorani, Signal Processing Systems, Stimuli-responsive Funct. Materials & Dev., Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
VLC ,driver ,Computer Networks and Communications ,Orthogonal frequency-division multiplexing ,Computer science ,Aerospace Engineering ,Visible light communication ,law.invention ,Amplitude modulation ,Bias tee ,law ,Electronic engineering ,Electrical and Electronic Engineering ,Computer Science::Information Theory ,Common emitter ,OFDM ,communication ,Transmitter ,LED ,power consumption ,transmitter ,Illumination ,Modulation ,Pulse-amplitude modulation ,efficiency ,Automotive Engineering ,Bit error rate ,PAM ,Light-emitting diode - Abstract
This work addresses the power penalty in a Visible Light Communication (VLC) emitter that re-uses illumination Light Emitting Diodes (LEDs) for high-speed communications. We quantify the effect of modulation depth for two widely explored modulation schemes in VLC, namely Orthogonal Frequency Division Multiplexing (OFDM) and Pulse Amplitude Modulation (PAM). Extra power is dissipated in the LED and in the modulator due to such modulation. Two popular highspeed VLC transmitter topologies, namely a Bias Tee (Bias-T) and a Serial FET (Serial-F), are compared in terms of efficiency, Extra Energy Per Symbol/Bit (EEPS/B) and complexity. This work presents a theoretical model and compares it to simulationresults. We show that PAM outperforms OFDM in terms of better Bit Error Rate (BER), larger dynamic range for modulation depth, less extra power loss, thus higher power efficiency for communication over an Additive White Gaussian Noise (AWGN) channel.
- Published
- 2019
- Full Text
- View/download PDF
3. Mitigating LED nonlinearity to enhance visible light communications
- Author
-
Bin Chen, Shokoufeh Mardanikorani, Xiong Deng, Kumar Arulandu, Jean-Paul M. G. Linnartz, A. M. Khalid, Yan Wu, Signal Processing Systems, Electro-Optical Communication, Information and Communication Theory Lab, Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
bandwidth ,VLC ,Photon ,Computer science ,channel capacity ,Charge carrier processes ,Visible light communication ,02 engineering and technology ,Multiplexing ,law.invention ,020210 optoelectronics & photonics ,Mathematical model ,law ,Radiative recombination ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Spontaneous emission ,Transient response ,Electrical and Electronic Engineering ,Lighting ,BER ,communication ,illumination ,Bandwidth (signal processing) ,LED ,nonlinearity ,Keying ,Light emitting diodes ,Nonlinear system ,Amplitude ,Pulse-amplitude modulation ,equalization ,Light-emitting diode - Abstract
This paper addresses the nonlinear memory effects in the response of typical illumination light emitting diodes (LEDs), in order to enhance the performance of visible light communication (VLC) systems. These LEDs have a limited bandwidth of only several MHz. To reflect the physical mechanisms in the quantum well, we describe the LED transient response by a nonlinear dynamic differential equation. Three different mechanisms of the nonlinearity are relevant in the double hetero-structure LEDs, which result in dynamic nonlinearities, that is, a mixture of nonlinearities and memory effects. Hitherto, generic pre-distorter and non-linear equalizers have been studied for the LEDs. Yet this paper shows that recombination rates of photon generation can be translated into an equivalent discrete-time circuit that can be inverted. This allows us to develop a new pre-distorter with a simpler and more efficient structure than previously studied and overly generic approaches. The novel pre-distorter along with a parameter estimation can effectively overcome LED nonlinearity for high-speed VLC with amplitude-based single carrier modulations, including ON-OFF keying and pulse amplitude modulation-4 systems, and with the multi-carrier orthogonal frequency-division multiplexing. We report experimentally obtained eye-diagrams, first to justify our choice for the LED model on which our nonlinear pre-distorter have been based, and second to verify the effectiveness in enhancing the VLC link performance to the extent predicted by our model.
- Published
- 2018
4. Bi-directional boost converter for emergency lighting
- Author
-
Marcel A. M. Hendrix and Kumar Arulandu
- Subjects
Switched-mode power supply ,Computer science ,business.industry ,Electrical engineering ,Battery (vacuum tube) ,Energy storage ,law.invention ,LED lamp ,law ,Boost converter ,Digital control ,Voltage source ,business ,Uninterruptible power supply - Abstract
This paper presents a distributed storage/emergency lighting upgrade circuit that can be added to LED lighting fixtures. In contrast to conventional designs that are mostly supplied by a voltage source, we present an example of an emergency lighting circuit that is supplied by a constant current source (LED driver) in charging/ lighting mode. We also compare the performance of the same circuit when it is supplied by a voltage source in emergency lighting mode by the battery. Notwithstanding its low component count, the discussed concept reaches an efficiency of 94%, and has a simple control scheme that provides dimming functionality for non-dimmable LED drivers.
- Published
- 2019
- Full Text
- View/download PDF
5. Novel post-distortion to mitigate LED nonlinearity in high-speed visible light communications
- Author
-
Kumar Arulandu, Shokoufeh Mardanikorani, Xiong Deng, Jean-Paul M. G. Linnartz, Signal Processing Systems, Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
bandwidth ,VLC ,Computer science ,Visible light communication ,Optical power ,02 engineering and technology ,law.invention ,020210 optoelectronics & photonics ,law ,0202 electrical engineering, electronic engineering, information engineering ,Spontaneous emission ,Voltage droop ,Transient response ,business.industry ,communication ,illumination ,Bandwidth (signal processing) ,LED ,Nonlinear optics ,nonlinearity ,Nonlinear system ,Pulse-amplitude modulation ,Optoelectronics ,business ,data rate ,equalization ,Light-emitting diode - Abstract
This paper addresses dynamic nonlinear effects in the response of typical illumination Light Emitting Diodes (LEDs) to increase the reliability and data rate in Visible Light Communication (VLC) systems. These power LEDs have a limited bandwidth of only several MHz. To conceive a practical receiver, we describe the LED transient response by a nonlinear dynamic differential equation from the physical mechanisms in the Quantum Well (QW) of Double Hetero-structured (DH) LEDs. It includes the transient nonlinear relation between the input current and injection electron concentration, as governed by the dynamic rate equation. Also, we consider the static nonlinear (typically quadratic) relation between the injection electron concentration and output optical power is described by a square operator. Further we consider the static nonlinear relation between the injection current and output optical power, caused by the efficiency droop. We propose a novel post-distorter to overcome LED nonlinearities for high-speed Pulse Amplitude Modulation (PAM)-4 systems. Its performance is validated with measurements of a commercial blue LED.
- Published
- 2019
- Full Text
- View/download PDF
6. Efficient amplitude modulator and ripple canceller for visible light communication
- Author
-
Jean-Paul M. G. Linnartz, Xiong Deng, Kumar Arulandu, Signal Processing Systems, Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
Frequency response ,Computer science ,Transistor ,Ripple ,Li-Fi ,Visible light communication ,020206 networking & telecommunications ,02 engineering and technology ,Optical Wireless Communication ,law.invention ,Amplitude modulation ,Visible Light Communication ,Capacitor ,020210 optoelectronics & photonics ,Amplitude ,law ,Modulation ,Pulse-amplitude modulation ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,LED drivers ,Light-emitting diode - Abstract
Power loss is an important design factor for Visible Light Communication (VLC). Dissipating only a few percent of the illumination power can still result into a few watts of heat generation which requires additional provisions for cooling the modulator circuit. We show that a transistor in series with LED can be used in linear operation to apply amplitude modulation which only marginally sacrifices efficiency. Yet, this requires a novel active control loop. We report its performance and frequency response for VLC modulation. We show that the modulator also effectively cancels mains ripple. Based on our experimental experience, we also propose a model to quantify the power losses and verify these for pulse amplitude modulation.
- Published
- 2019
7. Dynamic response-based LEDs health and temperature monitoring
- Author
-
Jean-Paul M. G. Linnartz, Kumar Arulandu, Anton Alexeev, Grigory Onushkin, Genevieve Martin, Signal Processing Systems, Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
Computer science ,Visible light communication ,Gallium nitride ,02 engineering and technology ,Smart driver ,Failure modes ,01 natural sciences ,Predictive maintenance ,law.invention ,chemistry.chemical_compound ,law ,OWC ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,Electrical response ,Instrumentation ,Electrical impedance ,Diode ,Optical response ,Applied Mathematics ,LED ,020208 electrical & electronic engineering ,010401 analytical chemistry ,Temperature ,Impedance ,Reliability ,Condensed Matter Physics ,0104 chemical sciences ,Solid-state lighting ,chemistry ,Defects ,Junction temperature ,Light-emitting diode - Abstract
This paper presents a number of novel methods to measure the junction temperature and to estimate the health of gallium nitride light-emitting diodes (LEDs). The methods are based on measurements of the dynamic impedance and optical output. Our experimental analysis reveals temperature sensitive parameters of the electrical and optical responses. Moreover, a correlation between the non-radiative current characterizing the active region defects and the small-signal impedance is shown. The demonstrated methods can be applied to enhance existing temperature-monitoring techniques. The derived dependencies also build a foundation for advanced in-field health monitoring of the LEDs using the infrastructure of visible light communication systems. Such methods and techniques are valuable for predictive maintenance of solid state lighting systems.
- Published
- 2020
- Full Text
- View/download PDF
8. Performance analysis for joint illumination and visible light communication using buck driver
- Author
-
Jean-Paul M. G. Linnartz, Yan Wu, Kumar Arulandu, Guofu Zhou, Xiong Deng, Signal Processing Systems, Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
VLC ,driver ,Computer science ,Ripple ,Visible light communication ,02 engineering and technology ,Interference (wave propagation) ,law.invention ,Amplitude modulation ,law ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,BER ,Buck converter ,communication ,illumination ,ripple ,020208 electrical & electronic engineering ,LED ,Shot noise ,020206 networking & telecommunications ,power consumption ,BPM ,Modulation ,Duty cycle ,efficiency ,Bit error rate ,Phase modulation ,buck converter ,Light-emitting diode ,Data transmission - Abstract
The visible light communication (VLC) can provide data transmission via the illumination light emitting diodes (LED). This paper introduces a new model to analyze the bit error rate (BER) of binary phase modulation in VLC for an arbitrary modulation depth and data duty cycle while taking into account both the Gaussian and signal-dependent shot noise. The impact of the driver design on the BER and its impact on ripple have not been considered in detail before. We compare two different LED driver schemes, namely directly adapting the driver control loop and binary shunting. We address data rate, BER, and power efficiency, for which we propose to use the extra energy per symbol above unmodulated light. We further introduce an analysis of the effect that (truncated) ripple interference has in the (matched or other) filter of the receiver. Ripple causes a harmful interference in VLC, and thus a BER expression is derived to include its effect. Two approximations are proposed to model the ripple interference, and their accuracies are compared by simulations. A low-pass filtering is proposed to alleviate the impact of ripple interference in VLC system.
- Published
- 2018
9. High yield expression and purification of Chikungunya virus E2 recombinant protein and its evaluation for serodiagnosis
- Author
-
Kaustuv Nayak, Pratima Ray, Murali Krishna Kaja, Rakesh Lodha, Anmol Chandele, Anil Verma, and Arockiasamy Arulandu
- Subjects
0301 basic medicine ,Protein Folding ,Enzyme-Linked Immunosorbent Assay ,Disease ,medicine.disease_cause ,Antibodies, Viral ,Sensitivity and Specificity ,Virus ,Immunoglobulin G ,Chromatography, Affinity ,Serology ,law.invention ,03 medical and health sciences ,Western blot ,Viral Envelope Proteins ,law ,Virology ,medicine ,Humans ,Chikungunya ,Antigens, Viral ,medicine.diagnostic_test ,biology ,virus diseases ,Recombinant Proteins ,030104 developmental biology ,Immunoglobulin M ,biology.protein ,Recombinant DNA ,Chikungunya Fever ,Chikungunya virus - Abstract
Disease caused by Chikungunya virus (CHIKV) is clinically characterized by sudden-onset of fever and severe arthralgia, which may persist for weeks, months, or years after acute phase of the infection. CHIKV is spreading globally; in India it first appeared in the 1960s followed by a quiescent period and then a full-blown remergence in 2006 and sporadic persistence since then. Despite a large number of commercially available diagnostic kits for CHIKV, clinical preparedness and diagnostics suffer from sub-optimal assays. An international diagnostic laboratory survey suggested that there is a critical need for improved CHIKV diagnostics especially in the early acute phase of illness. With the recent studies indicating that a vast majority of human humoral response in CHIKV infection is directed against E2 protein, this supports strong interest to develop CHIKV E2 based serological tests. However, methods to produce large amounts of CHIKV protein are limited. Here we report cloning, expression and purification methods for obtaining a truncated 37kDa Chikungunya E2 protein at a high yield of 65-70mg/l. We found that this purified protein can be reliably used in ELISA and western blot to detect CHIKV specific antibodies in sera from patients who were PCR or IgM positive. Thus, using this protocol, laboratories can make large quantities of purified protein that can be potentially used in CHIKV serological analysis.
- Published
- 2016
10. Effect of buck driver ripple on BER performance in visible light communication using LED
- Author
-
Yan Wu, Guofu Zhou, Jean-Paul M. G. Linnartz, Xiong Deng, Kumar Arulandu, Signal Processing Systems, Signal processing for communications, Lighting and IoT Lab, and Center for Wireless Technology Eindhoven
- Subjects
Buck converter ,Computer science ,business.industry ,Energy conversion efficiency ,Ripple ,Visible light communication ,law.invention ,Amplitude modulation ,law ,Electronic engineering ,Bit error rate ,Telecommunications ,business ,Pulse-width modulation ,Light-emitting diode - Abstract
This paper analyses the communication performance for visible light communication (VLC) with Manchester encoded amplitude modulation. In particular, it considers the ripple generated by the LED driver as an important noise contribution for VLC. The ripple depends on the oscillation frequency of the converter which typically is chosen to satisfy other performance criteria such as power conversion efficiency. This paper models the ripple as an additional noise if a buck converter LED driver is adapted for VLC. We argue that ripple can as a worst case be modeled as a random binary offset in the bit detection that randomly affects the distance between the data signal and the decision threshold. We derive expressions for the BER, propose approximations and we compare these with a simulation.
- Published
- 2015
- Full Text
- View/download PDF
11. Cloning, expression and purification of Chikungunya virus E2 recombinant protein in E.coli
- Author
-
Anil Verma, Murali-Krishna Kaja, Pratima Ray, Anmol Chandele, and Arockiasamy Arulandu
- Subjects
Cloning ,Pathology ,medicine.medical_specialty ,business.industry ,viruses ,food and beverages ,virus diseases ,Disease ,medicine.disease_cause ,medicine.disease ,Virology ,Arbovirus ,Virus ,law.invention ,Infectious Diseases ,Medical microbiology ,Parasitology ,law ,Poster Presentation ,parasitic diseases ,medicine ,Recombinant DNA ,Chikungunya ,business - Abstract
Background Chikungunya virus infection is an emerging arbovirus disease. While many infected individuals recover after primary illness, others suffer from persistent debilitating arthralgia that can last for months to years. Currently, there are no immune correlates, vaccines, therapies or robust diagnostics that can affectively prevent, treat or diagnose Chikungunya. Therefore, this study focuses on development of a better diagnostic assay for Chikungunya infection.
- Published
- 2014
- Full Text
- View/download PDF
12. Electron Microscopy and Single Particle Analysis of a Mycobacterial Preprotein Translocation, ATPase
- Author
-
Andreas Holzenburg, James C. Sacchettini, S Arulandu, and Christos G. Savva
- Subjects
Crystallography ,biology ,Chemistry ,law ,ATPase ,biology.protein ,Biophysics ,Single particle analysis ,Chromosomal translocation ,Electron microscope ,Instrumentation ,law.invention - Published
- 2003
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.