Data Transmission Applications Research Articles

Opto- Pyro Trains for Space Systems - Gains Provided by Opto-Pyro Technology in Terms of Safety on Launchers

ABSTRACT The Redesign of pyro train seems to be mandatory for next generation of European launchers, in order to be compliant with new requirements coming from: • European community: health regulations, REACH and RoHs requirements … • Agencies and customers: Cost reduction, Mass improvement, obsolescence risks reduction, robust design and versatility for any mission… • Prime contractors: Safety improvements for pyro supply chain and AIT teams, explosive trains monitoring, dual components … • Pyro Industries: «continuous» manufacturing to guarantee knowledge and competencies for the whole life of launcher manufacturing Maturation and developments done since 1970 concerning Optic, optronique and explosive systems highlighted great opportunities to merge these so matured technologies into opto-pyrotechnic system. But at this moment the energy ratio of such optic emitters was too low, to be applied into a launch vehicle. Since a decade great effort had been done by industries to provide more and more powerful laser emitters such as laser diodes for main data transmissions applications and strong needs rising from Industries, Aeronautics, Medicine, nuclear research The maturity of powerful and miniaturized optic components becoming COTS at the beginning of year 2000 accelerate their integration into new field such as aircraft data transmission applications. In addition the very good REX acquired through end users operations (civil and military fields), allow aircraft companies to spread this optic technology into more and more safety functions. The heritages coming from telecom and aircraft industries allow to set up and spread new type of portative monitoring tools to check any optical harness, detecting in a safe way any failure transmission and localize with a cm class accuracy any weak connection. The maturity level of optronique and the robustness demonstrated within a large range of applications give confidence to space engineers for analyzing its implementation into space systems, with a guarantee of long term technologies availability. The ability of optical fibre to transfer high amount of energy given by a very small laser diode, allow pyro designers to implement this technology into the first element of the pyro train: the initiator. This main evolution highlights several improvements on launcher pyro trains, increasing mainly their safety levels. The safety advantages given by Opto-pyro are addressing several fields such as: • Ground aspect during preparations and operations • Functional aspects • Industrial and Prime concerns AIRBUS Defence & Space through ASTRIUM-ST and Aerospatiale studies has been actively involved into Opto-pyro activities for a long time. The amount of Opto-pyro demonstration and justification has been accelerated since 2010 thanks to a special AIRBUS-DS R&T effort, focusing on TRL, IRL and MRL. Step by step, AIRBUS-DS manage to set up Opto-pyro train maturation from TRL4-IRL1, based on demonstrators and representative demonstrations of launcher configuration. These on going demonstrations will lead to a TRL6-IRL3 level in 2014. The higher safety level demonstrated by Opto-pyro train compared to the electro-pyro safety trains used on current space systems, allow implementing this new Opto-pyro technology on any new safety systems to be developed.

An Analog-Digital Clock DLL Control Circuit Used for High-Speed High-Resolution Digital-to-Analog Converter

An analog-digital clock delay locked loop (DLL) control circuit is proposed to detect and adjust the analog-digital clock phase difference in real time in a 14-bit 2GSPS digital-to-analog converter (DAC). To achieve a reasonable analog-digital clock phase difference, a digitally controlled delay line (DCDL) should be able to provide a total clock delay up to 1024ps. Such fine control is realized by a control block tracking and maintaining the precise phase relationship between analog and digital clock domains. The control circuit is realized by designing a digital finite state machine (FSM) carefully. The proposed circuit is implemented in 0.18μm CMOS technology. Simulation results show that the proposed circuit performs well in various conditions in high speed data transmission applications.

Robust and Imperceptible Dual Watermarking for Telemedicine Applications

In this paper, the effects of different error correction codes on the robustness and imperceptibility of discrete wavelet transform and singular value decomposition based dual watermarking scheme is investigated. Text and image watermarks are embedded into cover radiological image for their potential application in secure and compact medical data transmission. Four different error correcting codes such as Hamming, the Bose, Ray-Chaudhuri, Hocquenghem (BCH), the Reed---Solomon and hybrid error correcting (BCH and repetition code) codes are considered for encoding of text watermark in order to achieve additional robustness for sensitive text data such as patient identification code. Performance of the proposed algorithm is evaluated against number of signal processing attacks by varying the strength of watermarking and covers image modalities. The experimental results demonstrate that this algorithm provides better robustness without affecting the quality of watermarked image.This algorithm combines the advantages and removes the disadvantages of the two transform techniques. Out of the three error correcting codes tested, it has been found that Reed---Solomon shows the best performance. Further, a hybrid model of two of the error correcting codes (BCH and repetition code) is concatenated and implemented. It is found that the hybrid code achieves better results in terms of robustness. This paper provides a detailed analysis of the obtained experimental results.

High-Resolution All-Digital Duty-Cycle Corrector in 65-nm CMOS Technology

In high-speed data transmission applications, such as double data rate memory and double sampling analog-to-digital converter, the positive and negative edges of the system clock are utilized for data sampling. Thus, these systems require an exact 50% duty cycle of the system clock. In this paper, two wide-range all-digital duty-cycle correctors (ADDCCs) with output clock phase alignment are presented. The proposed phase-alignment ADDCC (PA-ADDCC) not only achieves the desired output/input phase alignment, but also maintains the output duty cycle at 50% with a short locking time. In addition, the proposed high-resolution ADDCC (HR-ADDCC) without a half-cycle delay line can improve the delay resolution and mitigate the delay mismatch problem in a nanometer CMOS process. Experimental results show that the frequency range of the proposed ADDCCs is 263-1020 MHz for the PA-ADDCC and 200-1066 MHz for the HR-ADDCC with a DCC resolution of 3.5 and 1.75 ps, respectively. In addition, the proposed PA-ADDCC and HR-ADDCC are implemented in an all-digital manner to reduce circuit complexity and leakage power in advanced process technologies and, thus, are very suitable for system-on-chip applications.

Optically Allowed Photoluminescence from a Direct-Gap Si-Ge Superstructure on Si0.4Ge0.6

Light emission from Si nanostructures has been of great interest for some time now owing to the need for silicon-based light sources for applications in silicon photonics. Both Si and Ge possess indirect band gaps, which makes them very inefficient light emitters. Band gap engineering has been proposed as one way to overcome this limitation and although light emission with greatly improved efficiency has been obtained at low temperatures the emission at room temperature is still very weak, because of exciton dissociation. Recently, through employing novel band gap engineering computations, entirely new Si/Ge [M. d’Avezac, J.-W. Luo, T. Chanier, and A. Zunger, Phys. Rev. Lett. 108, 027401 (2012)] and Si [H. J. Xiang, B. Huang, E. Kan, S.-H. Wei, and X. G. Gong, Phys. Rev. Lett. 110, 118702 (2013)] supercell structures possessing direct gaps have been proposed. According to d’Avezac et al., a SiGe2Si2Ge2SiGen superstructure should have a direct and dipole-allowed gap of 0.863 eV, which is ideally suited for optical fiber data transmission applications. Here we report on the growth of such a structure and its optical properties. Two similar samples were prepared by different growth methods: molecular beam epitaxy (MBE) and solid phase epitaxy (SPE). In both samples the superstructure (terminated with n = 12 monolayers of Ge) was grown on a 30-nm thick buffer layer of Si0.4Ge0.6 on a 5 µm thick relaxed buffer layer of Si0.4Ge0.6on a 750 µm thick (001) Si substrate. The photoluminescence (PL) spectra were measured using a Bomem DA3 FTIR spectrometer, with the samples excited at low temperatures with either 70 mW of 405 nm or 35 mW of 458 nm laser light.Photoluminescence (PL) spectra obtained at 6 K with excitation at 405 nm are shown in Fig. 1. Similar spectra were obtained with 458 nm excitation. No PL was detected from the two samples in the energy range 1000-1850 meV or at room temperature. The sharp drop at low energy near 700 meV is due to the cut-off in the instrumental response. A strong low-energy PL doublet is seen, with peaks near 780 and 820 meV, together with a much weaker peak at 872 meV. The ratio of intensities of the strong and weak peaks is the same in both samples. The intensities of all three PL peaks decrease with increasing temperature up to 25 K, but the weak peak decreases in intensity faster than that of the strong peaks. The weak peak at 872 meV is most likely the dipole-allowed direct-gap transition expected at 0.863 eV in the superstructure. The small difference in energy between theory and experiment could be the result of a difference in strain within the layer in the sample compared with the ideal (perfect) modeled structure or from assumptions in parameter values in the model. The strong peaks at 820 and 780 meV are assigned to the no-phonon and transverse-optic-phonon emission lines, respectively, of the Si0.4Ge0.6 buffer layer. The ~40 meV separation between the two strong peaks is characteristic of the phonon energies in SiGe alloys. The energies of the peaks, however, are much lower than that expected for a bulk Si0.4Ge0.6 alloy (~0.97 eV). The energies and general appearance of these peaks is reminiscent of what has been obtained from PL studies of SiGe nanostructures imbedded in Si. It is therefore likely that this PL arises predominately at the Si0.4Ge0.6/superstructure interface where there is type-II band alignment. In conclusion, we have obtained experimental evidence of the predicted direct-gap optically-allowed transition in a special supercell comprised of a number of ultrathin layers of Si and Ge.

Circularly Polarized Proximity-Fed Microstrip Array Antenna for Micro Satellite

Design of circular polarization microstrip antenna array was developed to support micro-satellite technology. Circular polarization antenna array used for data transmission applications operating in the S band frequencies from the satellite to the ground station . In this study of the patch array using proximity coupling techniques in this study to obtain high gain and wide of bandwidth. The structure of the antenna array design consists of four identical square patch elements and to use the concept of corporate transmission line fed power divider network uses three transformers quarter-lambda T-junction. Bandwidth impedance matching for resonance between two patches is ¾ l antenna system for center frequency of 2.25 GHz. The antenna is designed using the method of moments through simulation with microwave office software applications. The results of simulations and measurements obtained antenna parameters, such as: bandwidth of return loss <-10 dB above 100 MHz resonant frequency shifted to 1.75%, VSWR (1 to 2), the bandwidth of axial ratio <3 dB is 1.6% (narrowband) and the maximum directivity (gain) is 9.128 dB. Overall study results showed good performance antenna array with circular polarization properties, high gain and operates in the S band frequency micro satellite system.

High-Speed GeSi Electroabsorption Modulator on the SOI Waveguide Platform

Following significant research and development work over the past few years, silicon photonics has become a promising candidate to provide low-power, low-cost, and high-speed photonic links for telecommunication, data communication, and interconnect applications. A high-speed optical modulator is one of the critical components for these links. In this paper, we report on our recent progress in the development of a GeSi electro-absorption (EA) modulator based on the Franz-Keldysh effect (FKE) integrated in a 3-μm silicon-on-insulator (SOI) platform. We first discuss the FKE in GeSi, and describe the EA modulator device design and fabrication. We then report on the performance of the fabricated device. Finally, we describe the monolithic integration of four modulators with a four channel wavelength division multiplexing (WDM) echelle grating to demonstrate a 112 Gbit/s (4 × 28 Gbit/s) WDM transmitter chip. This chip establishes silicon photonics as an enabling technology for low-power and low-cost data transmission applications.

Design of Wireless Intelligent Home Control System Based on Zigbee Technology

Zigbee technology is a kind of bi-directional wireless communication technology characterized by close distance, low complexity, low power consumption, low speed and low cost. It is mainly used for data transmission of various electronic equipments with short distance, low power consumption and low transmission speed, as well as application of typical periodic data, intermittent data and low reaction time data transmission. This thesis first of all makes an analysis of characteristics of zigbee technology, based on which the design of wireless intelligent home control system based on zigbee technology is proposed. Finally, it gives an analysis of the daily management and maintenance of intelligent system, so as to contribute to further studies.

High Dose Gamma Irradiation of Lasers and p-i-n Photodiodes for HL-LHC Data Transmission Applications

Lasers and photodiodes for high luminosity large Hadron collider (HL-LHC) data transmission applications were irradiated with a 1-Gy dose of 60Co gammas. No change was observed in the performance of the lasers tested, and an order of magnitude increase in the leakage current of the InGaAs photodiodes was measured.

SDR: A Stable Direction-Based Routing for Vehicular Ad Hoc Networks

A stable and reliable routing mechanism for vehicular ad hoc networks (VANETs) is an important step toward the provision of long data transmission applications, such as file sharing and music download. Traditional mobile ad hoc network (MANET) routing protocols are not suitable for VANET because the mobility model and environment of VANET are different from those of traditional MANET. To solve this problem, we proposed a new stable routing algorithm, called stable directional forward routing. The novelty of the proposed routing protocol is its combining direction broadcast and path duration prediction into ad hoc on-demand distance vector routing protocols, which including: (1) Nodes in VANET are grouped based on the position, only nodes in a given direction range participating in the route discovery process to reduce the frequency of flood requests, (2) Route selection is based on the link duration while not the hops or other metrics to increase the path duration, (3) Route discovery is executed before the path expiration in order to decrease the end to end delay. The performance of the new scheme is evaluated through extensive simulations with Qualnet. Simulation results indicate the benefits of the proposed routing strategy in terms of decreasing routing control packet, reducing the number of link-breakage events, improving the packet delivery ratio and decreasing the end-to-end delay.

A Novel Lattice Architecture for High Speed Discrete MultiTone (DMT) Modulation

The Discrete MultiTone (DMT) modulation system is an attractive method for a high speed data transmission over a non- flat channel with possible colored noise. The IFFT is used in its transmitter in order to divide the available frequency spectrum into large independent narrow band sub-channels. A high speed and an efficient lattice architecture is proposed to implement the IFFT. This will speed up the DMT transmitter, so that, it can be easily used in any real time data transmission application. The proposed IFFT lattice architecture achieves approximately 58%, 39%, and 50% savings in gate count, power consumption, and area compared to the state of the art IFFT architectures that use conventional lattice structure. The proposed IFFT lattice architecture can perform high speed data transmission at 118 MHz. This allows the DMT transmitter to be easily integrated in any real time data transmission system.

Anti-Synchronization of Hyperchaotic Pang and Hyperchaotic Wang-Chen Systems Via Active Control

Hyperchaotic systems are chaotic systems having more than one positive Lyapunov exponent and they have important applications in secure data transmission and communication. This paper applies active control method for the synchronization of identical and different hyperchaotic Pang systems (2011) and hyperchaotic Wang-Chen systems (2008). Main results are proved with the stability theorems of Lypuanov stability theory and numerical simulations are plotted using MATLAB to show the synchronization of hyperchaotic systems addressed in this paper.

Broadband Packaging of Photodetectors for 100 Gb/s Ethernet Applications

The packing structure of functional modules is a major limitation in achieving a desired performance for 100 Gb/s ethernet applications. This paper presents a methodology of developing advanced packaging of photodetectors (PDs) for highspeed data transmission applications by using 3-D electromagnetic (EM) simulations. A simplified model of the PD module is first used to analyze and optimize packaging structures and propose an optimal packaging design based on the simplified model. Although a PD module with improved performance proved the success of the optimal packaging design, the simplified model could not identify other important bandwidth limitation effects. Therefore, a full 3-D EM model of PD modules is developed to predict the optical-to-electrical response of the module, and with this model, it is possible to identify a critical mode mismatch effect as another important factor of limiting the bandwidth of PD modules. After eliminating the mode mismatch effect by improving the chip-conductor-backed coplanar waveguide transition, a final optimal packaging structure is implemented for the PD module with reduced attenuation up to 100 GHz and a broader 3-dB bandwidth of more than 90 GHz. Furthermore, the PD module exhibits excellent performance under the high-speed data-transmission experiment with 107 Gb/s data rate.

MHealth in Sub-Saharan Africa

Mobile phone penetration rates have reached 63% in sub-Saharan Africa (SSA) and are projected to pass 70% by 2013. In SSA, millions of people who never used traditional landlines now use mobile phones on a regular basis. Mobile health, or mHealth, is the utilization of short messaging service (SMS), wireless data transmission, voice calling, and smartphone applications to transmit health-related information or direct care. This systematic review analyzes and summarizes key articles from the current body of peer-reviewed literature on PubMed on the topic of mHealth in SSA. Studies included in the review demonstrate that mHealth can improve and reduce the cost of patient monitoring, medication adherence, and healthcare worker communication, especially in rural areas. mHealth has also shown initial promise in emergency and disaster response, helping standardize, store, analyze, and share patient information. Challenges for mHealth implementation in SSA include operating costs, knowledge, infrastructure, and policy among many others. Further studies of the effectiveness of mHealth interventions are being hindered by similar factors as well as a lack of standardization in study design. Overall, the current evidence is not strong enough to warrant large-scale implementation of existing mHealth interventions in SSA, but rapid progress of both infrastructure and mHealth-related research in the region could justify scale-up of the most promising programs in the near future.

An FPGA Implementation of Secured Steganography Communication System

Steganography is the idea of hiding secret message in multimedia cover which will be transmitted through the Internet. The cover carriers can be image, video, sound or text data. This paper presents an implementation of color image steganographic system on Field Programmable Gate Array and the information hiding/extracting techniques in various images. The proposed algorithm is based on merge between the idea from the random pixel manipulation methods and the Least Significant Bit (LSB) matching of Steganography embedding and extracting method.In a proposed steganography hardware approach, Linear Feedback Shift Register (LFSR) method has been used in stego architecture to hide the information in the image. The LFSRs are utilized in this approach as address generators. Different LFSR arrangements using different connection unit have been implemented at the hardware level for hiding/extracting the secret data. Multilayer embedding is implemented in parallel manner with a three-stage pipeline on FPGA.This work showed attractive results especially in the high throughputs, better stego-image quality, requires little calculation and less utilization of FPGA area. The imperceptibility of the technique combined with high payload, robustness of embedded data and accurate data retrieval renders the proposed Steganography system is suitable for covert communication and secures data transmission applications.

Soliton-induced relativistic-scattering and amplification

Solitons are of fundamental importance in photonics due to applications in optical data transmission and also as a tool for investigating novel phenomena ranging from light generation at new frequencies and wave-trapping to rogue waves. Solitons are also moving scatterers: they generate refractive index perturbations moving at the speed of light. Here we found that such perturbations scatter light in an unusual way: they amplify light by the mixing of positive and negative frequencies, as we describe using a first Born approximation and numerical simulations. The simplest scenario in which these effects may be observed is within the initial stages of optical soliton propagation: a steep shock front develops that may efficiently scatter a second, weaker probe pulse into relatively intense positive and negative frequency modes with amplification at the expense of the soliton. Our results show a novel all-optical amplification scheme that relies on soliton induced scattering.

Reconfigurable Design of Rectangular to Polar Converter using Linear Convergence

In recent years, the growth of multimedia services and applications in digital data transmission has led to ever increasing demands of effective data transmission over the wired as well as wireless communication systems. Since digital communication systems need to deal with multimode and multiband operations on complex signals many-a-times, there is always a requirement of an efficient method for rapid phase and magnitude extraction. The proposed Rectangular to Polar Converter (RPC) has been implemented using fully parallel CORDIC, a Linear Convergence Algorithm, in vectoring mode. The design is synthesized with ISE 10.1 software, and implemented on 2v3000fg676-4. Synthesis results show that the design is able to work at 177.620 MHz with less hardware requirements. General Terms A rectangular to polar conversion is required so that transmitters must accommodate constant envelop signals as well as non-constant envelop signals to achieve multimode and multiband operations. In burst-mode communication systems, a rapid carrier is crucial. Hence a fast rectangular-topolar conversion is needed. Delay-matching of phase as well as amplitude is crucial so that the restoration of the transmitted data at the receiver may be not be imperfect if the delays are unmatched.

Experiment of substrate integrated waveguide interconnect measurement for high speed data transmission application

AbstractSubstrate integrated waveguide (SIW) has been used as a high speed interconnect for digital applications. The output eye diagram is an important indicator for evaluating the performance of the interconnect and the design of the driver and receiver units. This article studies the effect on eye diagrams based on improved driver and receiver design for a SIW interconnect system. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2012

3-D transponder antennas for future SHF RFID applications

Abstract. The radio frequency identification (RFID) technology is omnipresent since a few years. Some of the most popular fields of application are the use for security tasks, for logistics and for the consumer segment. For example, chip card or key ring sized RFID transponders can allow wireless access to secured rooms. The number of applications for wireless data transmission for the identification and tracking of objects increases every year. There is a large development need for highly functional and inexpensive RFID transponders due to the ever-increasing demand on improved reliability, higher data rates and read and write ranges of the RFID systems. Therefore, research was performed on new 3-D transponder antennas for the Super High Frequency Band around 5.8 GHz. Additionally, wave propagation effects and the influence of different dielectric environments were considered. Parallel to the design of the novel antenna structures, the printing process for inexpensive manufacturing was investigated. The gained results are the basis for prospective RFID applications.

Drift Correction Modulation scheme for digital signal processing

The article describes a new method of embedding and extracting the digital watermark in an acoustic signal, which operates in the frequency domain and uses a drift correction modulator of the watermark’s phase angle, as well as a precise correction procedure of the watermark signal to the minimum masking threshold. The Drift Correction Modulation (DCM) has been worked out for the needs of the watermarking system with a large data payload and robustness against degrading factors which occur during signal processing. The digital watermark embedded in the original signal using the DCM method is inaudible and robust against the majority of degrading factors. The DCM method may be used in Digital Signal Processing applications, e.g. for a hidden authentication of subscribers in telecommunication channels or for determining the output phase mistuning of devices. DCM is characterized by a high normalized data payload of the watermark signal and may be implemented in applications of hidden and secure data transmission. The paper presents the results of auditory tests according to the ITU-R 1116-1 standard; moreover, results of the watermark extraction tests in a VHF radio link, with the use of military tactical radio stations have been presented.