Digital Modulation Research Articles

Effect of Line-of-sight Channels on DC-biased Optical Filter Bank Multicarrier Visible Light Communication with Multiple LED Arrays

This paper investigates the impact of propagation delay and channel loss due to the use of multiple LED arrays in visible light communication (VLC) systems based on filter bank multicarrier (FBMC) modulation. FBMC offers greater spectral efficiency, and asynchronous transmission and is a promising alternative scheme to orthogonal frequency division modulation (OFDM). The proposed FBMC model is based on 4-quadrature amplitude modulation (QAM) and 16-QAM formats and uses 100 symbols and 600 input bits per symbol. In this paper, the VLC-FBMC system is designed based on the line-of-sight (LOS) model under the additive white Gaussian noise (AWGN) channel. Comparison analyses between different bit rates in terms of bit error rate (BER), best sampling point, and signal-to-noise ratio (SNR) requirement have been carried out to show the delay and loss effect on communication quality and system performance. The results demonstrate that the proposed FBMC model achieves a bit rate of up to 29.296 Mbit/s with a low BER of 10-3 and less SNR penalty in high QAM formats, demonstrating its potential as a viable alternative to OFDM for future VLC systems.

Progressive Pattern Interleaver with Multi-Carrier Modulation Schemes and Iterative Multi-User Detection in IoT 6G Environments with Multipath Channels.

Sixth-generation (6G) wireless networks demand a more efficient implementation of non-orthogonal multiple access (NOMA) schemes for severe multipath fading environments to serve multiple users. Using non-orthogonal multiple access (NOMA) schemes in IoT 6G networks is a promising solution to allow multiple users to share the same spectral and temporal resource, increasing spectral efficiency and improving the network's capacity. In this work, we have evaluated the performance of a novel progressive pattern interleaver (PPI) employed to distinguish the users in interleaved division multiple access (IDMA) schemes, suggested by 3GPP guidelines as a NOMA scheme, with two multi-carrier modulation schemes known as single-carrier frequency-division multiple access (SC-FDMA) and orthogonal frequency-division multiplexing (OFDM), resulting in SC-FDMA-IDMA and OFDM-IDMA schemes. Both schemes are multi-carrier schemes with orthogonal sub-carriers to deal against inter-symbol interference (ISI) and orthogonal interleavers for the simultaneous access of multiple users. It has been suggested through simulation outcomes that PPI performance is adequate with SC-FDMA-IDMA and OFDM-IDMA schemes in terms of bit error rate (BER) under multipath channel conditions. Moreover, regarding bandwidth requirement and the implementation complexity of the transmitted interleaver structure, PPI is superior to the conventional random interleaver (RI).

Front-end electronics development of large-area SiPM arrays for high-precision single-photon time measurement

TRopIcal DEep-sea Neutrino Telescope (TRIDENT) plans to incorporate silicon photomultipliers (SiPMs) with superior time resolution in addition to photomultiplier tubes (PMTs) into its detection units, namely hybrid Digital Optical Modules (hDOMs), to improve its angular resolution. However, the time resolution significantly degrades for large-area SiPMs due to the large detector capacitance, posing significant challenges for the readout electronics of SiPMs in hDOM. We analyzed the influences of series and parallel connections when constructing a large-area SiPM array and designed a series-parallel connection SiPM array with differential output. We also designed a high-speed pre-amplifier based on transformers (MABA-007159) and radio frequency amplifiers (BGA2803), and an analog multi-channel summing circuit based on operational amplifiers (LMH6629). We measured the single photon time resolution (SPTR) of a 4 × 4 SiPM (Hamamatsu S13360-3050PE) array (12 × 12 mm2) of approximately 300 ps FWHM. This front-end readout design enables the large-area SiPM array to achieve high-precision single photon time measurement in one readout channel.

Analysis of Students’ Needs and Characteristics toward Science to Support Differentiated Learning of Kurikulum Merdeka

The problem that occurs in the implementation of Kurikulum Merdeka is the limited of differentiated and integrated Computational Thinking (CT) teaching materials provided by the government which can be used by teachers to direct students to think computationally thinking while focus to students' learning needs, especially in science learning which is a developmental milestone of science development. The aims of the research are to analyze students’ needs and character mapping of students toward the development of differentiated digital modules integrated CT in science subject. The method used in this research is a qualitative descriptive method involving 10 junior high schools that have implemented Kurikulum Merdeka. The population in this study was 19,034 students of 101 junior high schools in Bireuen District. Meanwhile, the sample used in this research was 260 junior high school students from 10 schools in Bireuen District. From the results of data analysis, it was found that the proportion of learning styles for junior high school students in Bireuen District is dominated by auditory learning styles. Furthermore, the distribution of multiple intelligences is dominated by students with logical/mathematic intelligence. Lastly, the student perceives that science learning is enjoyable

Centralized full-duplex seamless photonic mmW fronthaul link based on phase modulation

We experimentally demonstrate a photonic full-duplex seamless millimeter wave fronthaul link, based on phase modulation, to address the challenges arising from the increased demands on the mobile fronthaul capacity and network densification toward 5G and beyond. The proposed system relies on phase modulation techniques, implemented at both the central office (CO) and remote radio head (RRH), to achieve optical frequency up-conversion of the downlink (DL) signal and optical modulation of the down-converted uplink (UL) signal. Furthermore, our approach includes the frequency down-conversion of the 40 GHz UL signal through an optically generated local oscillator (LO) signal in the RRH, while the laser employed for UL data transmission is situated at the CO, simplifying the remote site’s equipment. An optical waveshaper serves here as a programmable optical filter to provide signals for DL frequency up-conversion, LO generation, and also the optical carrier for UL transmission. In our experimental validation, we have tested our proposed system using 64-quadrature amplitude modulation (64-QAM) for the DL at a frequency of 41 GHz and quadrature phase shift keying (QPSK) for the UL at a frequency of 40 GHz. Notably, our results demonstrate the successful transmission of up to 200 MHz bandwidth for both digital modulation schemes, all while maintaining the error vector magnitude (EVM) well below the specified threshold. Additionally, when employing 5G new radio (NR) orthogonal frequency-division multiplexing (OFDM) signals with the same modulation formats for both links in full-duplex communication, we achieved EVM values as low as 5.2% for the DL and 6.9% for the UL, further highlighting the efficacy and robustness of our proposed solution.

Jobco Digital Module to Improve Student Learning Outcomes

This research aims to develop a product in the form of a digital module with the Canva platform and flipbook maker to improve student learning outcomes in cost accounting courses on the topic of cost of orders. Digital modules make it easy for students to access and increase students' interest in learning. This development research uses the ADDIE research design and development model. The research results found that the feasibility level in terms of media was very good with a score of 94%, while in terms of feasibility the digital module material developed received a score of 95% with very feasible criteria. The effectiveness results show that the digital module is able to improve student learning outcomes on the topic of cost of goods ordered. Educators are required to be creative in developing teaching materials, so digital modules are a form of creativity in teaching materials by presenting audio, visuals, animation and flexibility in use.

The Effect of Digital-Based Interactive Modules to Improve Student’s Critical Thinking Skills and Learning Motivation on Biology Learning

Biology learning is learning that requires teaching materials that can facilitate the delivery of abstract and complex material. This research aims to determine the effect of digital-based interactive modules on students' critical thinking skills and learning motivation at SMA Negeri 9 Bengkulu City. This research is a type of Quasi-Experimental research. The sample used in collecting research data was 65 students taken from class X MIPA 2 as the experimental class and X MIPA 3 as the control class. The instruments used were critical thinking skills test sheets and student learning motivation questionnaires. The results showed that students' critical thinking skills and learning motivation were better compared to the control class. This is shown by the significance value for these two variables, namely 0.00 0.05. The results of this research confirm that the use of teaching materials in the form of interactive digital modules in biology learning is effective in facilitating students to develop their thinking skills. The use of teaching materials that utilize technology will foster students' learning motivation because they are considered relevant to students' learning needs in the current technological era.

The Power Board of the KM3NeT Digital Optical Module: Design, Upgrade, and Production

The KM3NeT Collaboration is building an underwater neutrino observatory at the bottom of the Mediterranean Sea, consisting of two neutrino telescopes, both composed of a three-dimensional array of light detectors, known as digital optical modules. Each digital optical module contains a set of 31 three-inch photomultiplier tubes distributed over the surface of a 0.44 m diameter pressure-resistant glass sphere. The module also includes calibration instruments and electronics for power, readout, and data acquisition. The power board was developed to supply power to all the elements of the digital optical module. The design of the power board began in 2013, and ten prototypes were produced and tested. After an exhaustive validation process in various laboratories within the KM3NeT Collaboration, a mass production batch began, resulting in the construction of over 1200 power boards so far. These boards were integrated in the digital optical modules that have already been produced and deployed, which total 828 as of October 2023. In 2017, an upgrade of the power board, to increase reliability and efficiency, was initiated. The validation of a pre-production series has been completed, and a production batch of 800 upgraded boards is currently underway. This paper describes the design, architecture, upgrade, validation, and production of the power board, including the reliability studies and tests conducted to ensure safe operation at the bottom of the Mediterranean Sea throughout the observatory’s lifespan.

Accuracy of pace-mapping using an automated template matching module for site of origin identification of idiopathic outflow tract premature ventricular contractions

Abstract Background Activation mapping (AM) is the preferred approach to identify the premature ventricular complexes (PVC) site of origin (SOO) but it is limited when PVCs are infrequent. Pace-mapping (PM) is often used in combination with AM. Yet, relying on PM as sole guide for ablation requires a high accuracy for detecting the PVC SOO. Limited data exists on the accuracy of automated PM using PASO™ for identifying the SOO of idiopathic PVCs, particularly in the left ventricular outflow tract (LVOT). In two cohorts with both idiopathic and non-idiopathic PVCs, a PASO™ >94% was associated with ablation success. Purpose This study evaluated the accuracy of PM using the automated digital pace-matching module integrated in the CARTO mapping system for identifying the SOO of idiopathic outflow-tract PVCs. It also compared its accuracy in the LVOT versus the right ventricular outflow tract (RVOT). Methods Consecutive patients undergoing successful ablation of idiopathic outflow-tract PVCs were prospectively included. AM and PM were performed with a 3.5mm tip catheter. PM was conducted at 2mA, 5mA, or 10mA output, selecting the lowest output that captured at each site. Ablation was performed at the site of earliest bipolar local activation time. The PVC SOO was defined as the site of acute ablation success. The distance between the best PM (BPM) and the SOO and the areas defined by PM ≥98%, ≥96%, and ≥94% were measured. Long-term success was defined by a ≥80% reduction in PVC burden at 3-month follow-up. Results In total, 27 patients were included; 18 had PVCs from the RVOT and 9 from the LVOT. All procedures were acutely successful after a median of 2 (IQR 1-3) radiofrequency applications (RFA) in the RVOT and one (IQR 1-2) RFA in the LVOT. In the RVOT, the median BPM was 98.1% (98.0-98.6), the median distance from the BPM to the SOO was 3.5 mm (IQR 0–8.5mm) and the areas of PM ≥98%, ≥96%, ≥94% were 1.2cm2 (0.5 – 1.8), 3.4cm2 (1.5-4.7) and 7.1cm2 (4.9-11.1). In the LVOT, the median BPM was 95.5% (IQR 94.9 – 97.8%) and the median distance from the BPM to the SOO was 8 mm (IQR 2–15mm). Only 3/9 patients with LVOT PVCs had a BPM ≥96% (1/9 ≥98%) and in all 3, the PVC SOO was coincident with the BPM site. From the remaining 6 patients, 5 had a BPM ≥94% but only in 2/5 the PVC SOO was within the area defined by the BPM site. In 26/27 (96%) patients, no PVC recurrence was documented after 3 months (median burden 0% [IQR 0-0]). Conclusions The accuracy of using the best pace-match provided by PASO™ for identifying the PVC SOO in the RVOT is high, making it a suitable target for limited ablation when activation mapping is not possible because of insufficient PVCs. In the LVOT, the best pace-match is frequently lower than in the RVOT and it misses the PVC SOO in almost half of the patients. The previously suggested PM >94% cut-off seems to be insufficient to identify the PVC SOO in both the RVOT and LVOT.TablePacemap

Tourism Platforms and the Digital Biopolitics of Nature: An Interface Analysis of TripAdvisor in Patagonia-Aysén, Chile

This article investigates how digital platforms are implicated in the neoliberalization of conservation by turning nature and protected areas into tourism commodities. We mobilize Ash et al.’s (2018) heuristic of unit, vibration, and tone to analyze TripAdvisor’s interfaces for contributing, exploring, and reviewing nature-based points of interest in Patagonia-Aysén, Chile. We contend that digital tourism platforms express what we term digital environmental biopower, which designates these platforms’ capacities to enlist digital users as agents who engage in biopolitical practices such as classifying, scoring, and raking natural areas as objects whose value is reliant on their tourism attributes. We argue that these digital modulations both sustain and are sustained by an environmental biopolitical regime in which “pristine” natural areas are “made to live” or “allowed to die” in the global digitally mediated (eco)tourism marketplace.

Towards malaria elimination: a reflection about digital notification modules to improve malaria cases notification speed and follow-up in the Brazilian Amazon region

BackgroundHealth information systems (HIS) are a pivotal element in epidemiological surveillance. In Brazil, malaria persists as a public health challenge, with 99% of its occurrences concentrated in the Amazon region, where cases are reported through the HIS Sivep-Malaria. Recent technological advancements indicate that case notifications can be expedited through more efficient systems with broader coverage. The objective of this study is to analyse opportunities for notification within Sivep-Malaria and explore the implementation of mobile electronic devices and applications to enhance the performance of malaria case notifications and use.MethodsThis descriptive study analyses data on malaria-positive cases in the Brazilian Amazon from 2004 to 2022. Malaria Epidemiological Surveillance System (Sivep-Malaria) data were used. The Brazilian Amazon region area is approximately 5 million km2 across nine different states in Brazil. Data entry opportunities were assessed by considering the time difference between the 'date of data entry' and the 'date of notification.' Descriptive statistics, including analyses of means and medians, were conducted across the entire Amazon region, and for indigenous population villages and gold mining areas.ResultsBetween 2004 and 2022, 6,176,878 new malaria cases were recorded in Brazil. The average data entry opportunity throughout the period was 17.9 days, with a median of 8 days. The most frequently occurring value was 1 day, and 99% of all notifications were entered within 138 days, with 75.0% entered within 20 days after notification. The states with the poorest data entry opportunities were Roraima and Tocantins, with averages of 31.3 and 31.0 days, respectively. For indigenous population villages and gold mining areas, the median data entry opportunities were 23 and 15 days, respectively.ConclusionsIn malaria elimination, where surveillance is a primary strategy for evaluating each reported case, reducing notification time, enhancing data quality and being able to follow-up cases through computerized reports offer significant benefits for cases investigation. Technological improvements in Sivep-Malaria could yield substantial benefits for malaria control in Brazil, aiding the country in achieving disease elimination and fulfilling the Sustainable Development Goals.

Simulation design for Ro-FSO communications system by digital modulation schemes

Abstract The Ro-FSO system was designed using Opti System software (version 20), and its efficiency is evaluated in this study using two distinct digital modulators (PSK and DPSK). The proposed system consists of four transmission channels, each with its own wavelength (193.1, 193.2, 193.3, and 193.4 THz). The system was utilized to transmit data at three different rates (10, 20, and 40 Gbit/s) under four different levels of dust attenuation. Because of the large quantity of data retrieved, only results from two specific wavelengths (193.1 and 193.4 THz) were disclosed, as they exhibited the highest Q-factor and lowest bit error rate (BER). The study observed that the (DPSK) modulator surpassed the (PSK) modulator in multiple attenuation scenarios and had superior performance when transmitting data at speeds of 10 and 40 Gb/s. The wavelength of 193.4 THz performed optimally with both modulators in terms of wavelengths.

English Language Teaching Digital Module for Android-Based Food and Beverage Services

The Covid-19 pandemic forced the schools to conduct e-learning. The challenges are even greater for vocational schools since the students do practices using specific instruments. Thus, this study aimed to develop an Android-based digital module for teaching English for food and beverage services to help students learn English effectively through online learning. This study followed the 4D model of research and development study. The data of the study were collected through observation, documentation, expert judgment, and questionnaire. The data were analysed both qualitatively and quantitatively. This study successfully developed the final format of the module in the form of an electronic book consisting of eight units. In addition, the quality of the module can be categorized as very good material based on the questionnaire results, which were given to the related students, lecturers, and expert judges. The exercises provided in the module provide many opportunities for students to practice and learn. The implication of this finding has a potential to revolutionize the way that English is taught and learned. By providing students with access to high quality digital modules can help students to achieve the student’s English language learning in Food and Beverage Services. This research merely evaluates the module in the formative process.

Voltage balancing for active power filter using dual-frequency multicarrier modulation with balanced H-bridge control

In this paper, a switching control method integrated with voltage balancing feature is presented to manage operation of single-phase 5-level cascaded H-bridge (CHB) inverter as parallel-connected active power filter (PAPF), and at the same time maintain its voltage balance. CHB inverters are always preferred for PAPF due to their dominating features of modularity, flexibility and least components count. However, inherent voltage unbalance issues of CHB inverter which is due particularly to unequal switching operation across its individual H-bridge module have always been the most troublesome when handling CHB inverter. For consistent voltage balance across each H-bridge module, proportional-integral (PI) controller for voltage balancing control and multicarrier sinusoidal pulse-width modulation (MCSPWM) for switching control have commonly been integrated together. However, these conventional approaches do not directly address the issue of unequal switching. Hence, in this work, effort is performed to allow each individual H-bridge module to operate with balance switching pattern, by evenly distributing the PWM switching signal to them. Design concept of the proposed method is modeled in MATLAB-Simulink platform. To critically assess its effectiveness, comparative analysis involving two types of highly nonlinear rectifier loads and distorted grid is performed. The presented simulation findings confirmed effectiveness of the proposed method in maintaining voltage balance of the 5-level CHB inverter when mitigating harmonics under adverse grid.

ОДНОВИМІРНА ЗГОРТКОВА МОДЕЛЬ НЕЙРОННОЇ МЕРЕЖІ ДЛЯ ОБРОБЛЕННЯ СИГНАЛІВ З АМПЛІТУДНОЮ МОДУЛЯЦІЄЮ БАГАТЬОХ СКЛАДОВИХ

The processing of radio signals using artificial neural networks (ANNs) has great potential for research, which can be explained by the adaptability of ANNs to various transmission conditions and the ability to detect abstract patterns of changes in signal parameters. The article reviews the works of other authors devoted to different ways of using ANNs for processing radio signals. Taking into account the information in the reviewed works, the research task was formed, which consists in developing an optimized ANN model for radio signal processing. Signals with amplitude modulation of many components (AMMC) were chosen to form training samples for ANN. The choice of modulation type is justified by greater energy efficiency compared to other widely used digital modulation types, such as quadrature amplitude modulation. Mathematic basis of AMMC signal generation is described. The process of finding the coordinates of three component 8-AMMC signal constellation is explained, the formation of signals in the time plane based on the found coordinates is explained as well as their discretization and the addition of white noise. An iterative algorithm for generating initial data for ANN based on the described ratios is proposed. The general structure of one-dimensional convolutional neural network is considered. Functions of individual neurons, connections between them, the formation of layers and the convolution operation are described mathematically. On the basis of the previously given ratios, a final display of the network was formed. Specific dimensions and activation functions for layers are selected. The use of convolutional layers is justified by time invariance. Based on the reviewed mathematical models, selected activation functions and dimensions, a neural model was formed. The process of validating the effectiveness of the formed neural model is described, which is based on comparing the symbolic error probabilities of the proposed and reference models at different signal-to-noise ratios. The validation results are presented. The advantages of the obtained model over the previously proposed purely recurrent model and the AMMC reference receiver are explained.

Using cumulant analysis to recognize digital types of radio signal

Problem statement. Recognition of types of modulation of radio signals is an important task solved in radio engineering systems for various purposes. In radio monitoring tools, information about the type of modulation is used to identify unauthorized sources of radio emission and measure their parameters, in electronic warfare systems - when choosing a more effective type of interference, etc. The article substantiates the relevance of improving methods for recognizing digital types of modulation. It is shown that mixed cumulants of higher orders can be used as modulation features for recognizing types of modulation. Analytical expressions are given for calculating mixed cumulants up to the tenth order inclusive through the values of mixed moments and the value of mixed cumulants for radio signals with the most common types of digital modulation. Recommendations have been developed for the synthesis of algorithms for recognizing the type of modulation based on cumulant analysis. Goal. Obtain mathematical expressions for calculating mixed cumulants up to the tenth order inclusive and determine the values of mixed cumulants to recognize the most common digital types of modulation. Results. A general methodology has been developed for the synthesis of algorithms for recognizing the type of modulation based on cumulant analysis. Practical significance. Application of the developed approach in the design of radio-electronic systems makes it possible to obtain a high probability of correct recognition of digital types of modulation with a relatively low design complexity.

Design of Laser-Powered Opto-Electrical Current Transformer and Its Application in Electrical Automation of Substations

The novel power equipment represented by the Opto-Electrical Current Transformer (OECT) possesses unparalleled advantages compared to traditional Current Transformers (CTs), rendering it with vast potential in power systems. In the design of OECT, this study employs laser power supply and focuses on the overall perspective, particularly the design of the laser power supply module and the optical fiber digital transmission module. The laser power supply module selects a high-power semiconductor laser to provide power to the circuit, incorporating line filters, thermistor resistors, and a laser overcurrent protection circuit. An automatic temperature control circuit based on PI regulation is utilized to stabilize the working temperature of the laser diode (LD). The photoelectric conversion device PPC-6E achieves a maximum photoelectric conversion efficiency of 40%, and the MAX639 DC–DC conversion chip ensures stable output voltage. The optical fiber digital transmission module adopts a circuit composed of multiple NOR gate logic for electro-optical conversion, a low-power driving circuit based on the 74LVC1G07 chip, and the HFBR-2412 photoelectric converter to simplify the circuit board design. To achieve a higher communication baud rate, a quartz multimode optical fiber with a diameter of 62.5 μm is chosen. In the experimental phase, a simulation of high-power AC power with equal turns is conducted. The linearity/temperature test results demonstrate that the designed OECT in this study meets expectations. In the electrical automation test of substations, a comparison between traditional CTs and the designed OECT is carried out using traditional protection algorithms and optical differential protection algorithms. The results indicate that, compared to traditional protection algorithms, the optical differential algorithm using the designed OECT achieves faster protection times.

The PMT system of the TRIDENT pathfinder experiment

Next generation neutrino telescopes are highly anticipated to boost the development of neutrino astronomy. A multi-cubic-kilometer neutrino telescope, TRopIcal DEep-sea Neutrino Telescope (TRIDENT), was proposed to be built in the South China Sea. The detector aims to achieve ∼ 0.1 degree angular resolution for track-like events at energy above 100 TeV by using hybrid digital optical modules, opening new opportunities for neutrino astronomy. In order to measure the water optical properties and marine environment of the proposed TRIDENT site, a pathfinder experiment was conducted, in which a 100-meter-long string consisting of three optical modules was deployed at a depth of 3420 m to perform in-situ measurements. The central module emits light by housing LEDs, whereas the other two modules detect light with two independent and complementary systems: the PMT and the camera systems. By counting the number of detected photons and analyzing the photon arrival time distribution, the PMT system can measure the absorption and scattering lengths of sea water, which serve as the basic inputs for designing the neutrino telescope. In this paper, we present the design concept, calibration and performance of the PMT system in the pathfinder experiment.

DEVELOPMENT OF PROFILE DEVIATION ANALYSIS METHODOLOGY BLADE PEN OF RESEARCH LOT USING COMPRESSION AND INFORMATION CONVERSION METHODS

As part of the implementation of the concept of the “digital twin” of the Gas Turbine development, a methodology for analyzing deviations in the profile of the fan blade using the example of a research batch using compression and information conversion methods has been proposed. This approach allows detecting incorrectly measured blades, comparing the coordinates of the manufactured profile with those specified in the drawing simultaneously for all controlled sections of the blade, conducting an operational analysis and deciding on the need to take into account the actual geometry of the blades in the calculation models “as manufactured” transmitting the results to the digital platform module for creating digital twins for virtual tests of the actual configuration of the assembly or GTE as a whole.

Multisampling Digital Pulse-Width Modulator Based on Asymmetric Dual-Edge Carrier

Multisampling Digital Pulse-Width Modulator Based on Asymmetric Dual-Edge Carrier