Zeitschriftenartikel: „Modulation discrète“

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Nofal, Abdul-Nasser, Abdel-Nasser Assimi und Yasser M. Jaamour. „Joint Power Allocation and Bit-Loading for Multicarrier Systems with Discrete Modulation“. Mathematical Modelling of Engineering Problems 8, Nr. 4 (31.08.2021): 626–34. http://dx.doi.org/10.18280/mmep.080416.

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In this paper, we propose two algorithms for joint power allocation and bit-loading in multicarrier systems using discrete modulations. The objective is to maximize the data rate under the constraint of a suitable Bit Error Rate per subcarrier. The first algorithm is based on the Lagrangian Relaxation of the discrete optimization problem in order to find an initial solution. A discrete solution is found by bit truncation followed by an iterative modulation adjustment. The second algorithm is based on Discrete Coordinate Ascent framework with iterative modulation increment of one selected subcarrier at each iteration. A simple cost function related to the power increment per bit is used for subcarrier selection. A sub-optimal low complexity Discrete Coordinate Ascent algorithm is proposed that overcome the limitations of the Hughes-Hartogs algorithm. The Lagrangian Relaxation algorithm provides a suboptimal solution for non-coded system using M-QAM modulations, whereas the low complexity Discrete Coordinate Ascent algorithm provides a near optimal solution for coded as well as for non-coded system using an arbitrary modulation set. Numerical results show the efficiency of the proposed algorithms in comparison with traditional methods.

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JAMES, GUILLAUME. „NONLINEAR WAVES IN NEWTON'S CRADLE AND THE DISCRETE p-SCHRÖDINGER EQUATION“. Mathematical Models and Methods in Applied Sciences 21, Nr. 11 (November 2011): 2335–77. http://dx.doi.org/10.1142/s0218202511005763.

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We study nonlinear waves in Newton's cradle, a classical mechanical system consisting of a chain of beads attached to linear pendula and interacting nonlinearly via Hertz's contact forces. We formally derive a spatially discrete modulation equation, for small amplitude nonlinear waves consisting of slow modulations of time-periodic linear oscillations. The fully nonlinear and unilateral interactions between beads yield a nonstandard modulation equation that we call the discrete p-Schrödinger (DpS) equation. It consists of a spatial discretization of a generalized Schrödinger equation with p-Laplacian, with fractional p > 2 depending on the exponent of Hertz's contact force. We show that the DpS equation admits explicit periodic traveling wave solutions, and numerically find a plethora of standing wave solutions given by the orbits of a discrete map, in particular spatially localized breather solutions. Using a modified Lyapunov–Schmidt technique, we prove the existence of exact periodic traveling waves in the chain of beads, close to the small amplitude modulated waves given by the DpS equation. Using numerical simulations, we show that the DpS equation captures several other important features of the dynamics in the weakly nonlinear regime, namely modulational instabilities, the existence of static and traveling breathers, and repulsive or attractive interactions of these localized structures.

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Zhang, Hao Chi, Tie Jun Cui, Yu Luo, Jingjing Zhang, Jie Xu, Pei Hang He und Le Peng Zhang. „Active digital spoof plasmonics“. National Science Review 7, Nr. 2 (04.10.2019): 261–69. http://dx.doi.org/10.1093/nsr/nwz148.

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Abstract Digital coding and digital modulation are the foundation of modern information science. The combination of digital technology with metamaterials provides a powerful scheme for spatial and temporal controls of electromagnetic waves. Such a technique, however, has thus far been limited to the control of free-space light. Its application to plasmonics to shape subwavelength fields still remains elusive. Here, we report the design and experimental realization of a tunable conformal plasmonic metasurface, which is capable of digitally coding and modulating designer surface plasmons at the deep-subwavelength scale. Based on dynamical switching between two discrete dispersion states in a controlled manner, we achieve digital modulations of both amplitude and phase of surface waves with nearly 100% modulation depth on a single device. Our study not only introduces a new approach for active dispersion engineering, but also constitutes an important step towards the realization of subwavelength integrated plasmonic circuits.

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Ali, Weaam Talaat. „Performance of Discrete Wavelet Transform Based on OFDM with Adaptive Modulation“. International Journal of Engineering Research 4, Nr. 8 (01.08.2015): 419–25. http://dx.doi.org/10.17950/ijer/v4s8/804.

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Zheleznjak, V. K., S. V. Lavrov, M. M. Baranouski und A. G. Filipovich. „Mathematical model of speech signal leakage channels during discrete-quantified conversion“. Doklady BGUIR 18, Nr. 4 (25.06.2020): 89–95. http://dx.doi.org/10.35596/1729-7648-2020-18-4-89-95.

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The purpose of the article is to estimate the leakage channel of a discrete-quantized speech signal with amplitude-pulse modulation. Discrete-quantized analog-to-digital conversion of signals in the article is considered by the example of pulse-amplitude modulation. Development of mathematical model of speech signal leakage channels during discrete-quantified conversion is based on the spectral representation of periodic signals by Fourier series. A periodic pulse train of triangular shape as a measuring signal is proposed. Measuring signal of triangular shape has an advantage over a harmonic signal in the process of quantization noise extraction because it allows one to achieve higher accuracy during signal processing. To evaluate the channel security caused by amplitude-pulse modulation, a harmonic signal is used, which is generated from a periodic pulse sequence of a triangular shape by the Fourier transform method. As a result of constructing the spectrum of the amplitude-pulse modulated signal, it was found that for each harmonic component of the spectrum corresponding to the spectrum of the periodic sequence of pulses, side components corresponding to the spectrum of the modulating signal appear. This side components, together with the low-frequency component in the band of the speech signal, form an information leakage channel. The presence of source modulating signal in the amplitude-pulse modulated signal spectrum allows one to digest the security of the leakage channel of the speech signal with amplitude-pulse modulation by the low-frequency component of the modulating signal. The materials presented in the article are original and can be used in assessing the security of leakage channels of speech signals converted into digital form. In addition, the results obtained allow further studies of the security of speech signals during their inverse transformation from digital to the original signal.

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Zhou, Shiyi, Zhijun Zhang, Chuliang Zhou, Zhongpeng Li, Ye Tian und Jiansheng Liu. „A high-energy electron density modulator driven by an intense laser standing wave“. Laser and Particle Beams 37, Nr. 2 (30.04.2019): 197–202. http://dx.doi.org/10.1017/s0263034619000338.

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AbstractA high energy electron density modulator from a high-intensity laser standing wave field is studied herein by investigating the ultrafast motion of electrons in the field. Electrons converge at the electric field antinodes, and the discrete electron density peaks modulated by the field located at the corresponding laser phases of kx = nπ, (n = 0, 1, 2, …), that is, the modulation period is 1/2 the wavelength of the individual laser. We also discussed the influence of the laser parameters such as laser intensity and waist size on the beam modulator. It is shown that a long interaction length (waist) or sufficiently high field intensity is essential for relativistic electron density modulation.

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Xuhong Chu, Xuhong Chu, Liquan Dong Liquan Dong, Yuejin Zhao Yuejin Zhao, Xiaomei Yu Xiaomei Yu und and Yun Feng and Yun Feng. „Optical readout method based on time-discrete modulation for micro-cantilever array sensing“. Chinese Optics Letters 14, Nr. 10 (2016): 101102–6. http://dx.doi.org/10.3788/col201614.101102.

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Воловач, В. И. „Mathematical modeling of the correlation function and the energy spectra of the noise modulation function“. Informacionno-technologicheskij vestnik, Nr. 1(27) (15.03.2021): 77–92. http://dx.doi.org/10.21499/2409-1650-2021-27-1-77-92.

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Рассмотрены и проанализированы вопросы, связанные с математическим моделированием корреляционных функций и энергетических спектров функции помеховой модуляции. Показано, что при воздействии на сигнал узкополосной мультипликативной помехи в энергетическом спектре функции помеховой модуляции присутствует дискретная составляющая, мощность которой зависит от глубины фазовых искажений. При импульсно-флуктуационной модулирующей помехе с детерминированным тактовым интервалом энергетический спектр функции помеховой модуляции представляет собой сумму непрерывной и дискретной частей. The issues related to mathematical modeling of correlation functions and energy spectra of the noise modulation function are considered and analyzed. It is shown that when a signal is affected by a narrow-band multiplicative interference, a discrete component is present in the energy spectrum of the interference modulation function, the power of which depends on the depth of the phase distortion. In the case of pulse-fluctuating modulating interference with a deterministic clock interval, the energy spectrum of the interference modulation function is the sum of the continuous and discrete parts.

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Seetha, S., D. P. Sharma, V. N. Padmini, T. M. K. Marar, K. Kasturirangan, U. R. Rao und J. C. Bhattacharyya. „Periodic Modulations in the Optical Light Curves of EX Hydrae“. International Astronomical Union Colloquium 93 (1987): 193–96. http://dx.doi.org/10.1017/s0252921100104853.

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AbstractWe present here new results on the periodic modulations in the optical light curves of EX Hydrae observed during 1982–84. The period analysis has been done using synchronous summation and discrete Fourier transform methods. We report new periodicities at 34.7 min and 26.7 min apart from confirming the detection of 46.3 min modulation recently reported. We also include our data to derive the rate of decrease of the 67 min period.

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Zeng, Zhiyong, Xiaoliang Jin und Rongxiang Zhao. „Small-signal discrete-time modeling of digitally controlled three-phase PWM boost rectifier under balanced voltage“. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 36, Nr. 1 (03.01.2017): 18–47. http://dx.doi.org/10.1108/compel-03-2016-0113.

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Purpose The model for digitally controlled three-phase pulse width modulation (PWM) boost rectifiers is a sampled data model, which is different from the continuous time domain models presented in previous studies. The controller, which is tuned according to the model in continuous time domain and discretized by approximation methods, may exhibit some unpredictable performances and even result in unstable systems under some extreme situations. Consequently, a small-signal discrete-time model of digitally controlled three-phase PWM boost rectifier is required. The purpose of this paper is to provide a simple but accurate small-signal discrete-time model of digital controlled three-phase PWM boost rectifier, which explains the effect of the sampling period, modulator and time delays on system dynamic and improves the control performance. Design/methodology/approach Based on the Laplace domain analysis and the waveforms of up-down-count modulator, the small signal model of digital pulse width modulation (DPWM) in the Laplace domain is presented. With a combination of state-space average and a discrete-time modeling technique, a simplified large signal discrete time model is developed. With rotation transformation and feed-forward decoupling, the large-signal model is decoupled into a single input single output system with rotation transformation. Then, an integrated small signal model in the Laplace domain is constructed that included the time delay and modulation effect. Implementing the modified z-transform, a small-signal discrete-time model is derived from the integrated small signal model. Findings In a digital control system, besides the circuit parameters, the location of pole of open-loop transfer function is also related to system sampling time, affecting the system stability, and the time delay determines the location of the zero of open-loop transfer function, affecting the system dynamic. In addition to the circuit parameters discussed in previous literature, the right half plane (RHP) zero is also determined by the sampling period and the time delay. Furthermore, the corner frequency of the RHP zero is mainly determined by the sampling period. Originality/value The model developed in this paper, accounting for the effect of the sampling period, modulator and time delays on the system dynamic, give a sufficient insight into the behavior of the digitally controlled three-phase PWM rectifier. It can also explain the effect of sampling period and control delay time on system dynamic, accurately predict the system stability boundary and determine the oscillation frequency of the current loop in critical stable. The experimental results verify that the model is a simple and accurate control-oriented small-signal discrete-time model for the digitally controlled three-phase PWM boost rectifier.

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Dvornikov, Sergey, Sergey Dvornikov und Kirill Zheglov. „Noise Immunity of Single-Sideband Modulation Signals with a Controlled Carrier Level“. Informatics and Automation 22, Nr. 2 (17.03.2023): 261–88. http://dx.doi.org/10.15622/ia.22.2.2.

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Single-sideband modulation is actively used in the organization of communication through the ionospheric channel in the decameter range of radio waves. This is due to the fact that transmissions with single-sideband modulation make it possible to minimize the frequency band while maintaining the information transfer rate and at the same time increase the noise immunity of reception in relation to transmissions with amplitude and frequency analog modulation. At the same time, the widespread use of quadrature synthesis technologies has opened up new possibilities for the formation of transmissions with single-sideband modulation without the direct use of filtering procedures. An analysis of the implementation features of the method of quadrature synthesis of signals with single-sideband modulation showed that the introduction of an additional parameter into its procedures will allow you to control the residual level of the carrier wave, and thereby control the noise immunity of the reception. The opened opportunities made it possible to develop a method and a device for generating a single-sideband modulation signal with an adjustable level of the carrier wave that implements it. The technologies of quadrature synthesis of signals of amplitude modulation and single-sideband modulation with the suppressed carrier are considered both at the level of analytical modeling and using a standard quadrature modulator. The necessity of transition to the analytical form of representation of the modulating signal is substantiated. The role and place of the Hilbert converter in the formation of signals with single-sideband modulation are shown. Known technologies for generating single-sideband modulation signals with a stored pilot signal are considered. The possibility of controlling the value of the stored pilot signal at the level of quadrature synthesis procedures is substantiated. An analytical model and, based on it, a structural diagram have been developed that allow one to generate single-sideband modulation signals with an adjustable pilot signal level. The results of analytical modeling are demonstrated. The value of the provided energy gain as a result of regulation by the residual level of the carrier wave is calculated. Approaches to assessing the noise immunity of transmissions with single-sideband modulation are analyzed. An approach is proposed for calculating the bit error probability of SSB transmissions manipulated by discrete oscillations based on the results of energy redistribution between the carrier oscillation and the sideband, determined by the residual pilot signal level. Conclusions and proposals for the practical implementation of the results obtained are formulated.

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Lalas, Antonios X., Nikolaos V. Kantartzis und Theodoros D. Tsiboukis. „Piezoelectrically programmable electric-field driven LC (ELC) resonators acting as THz modulators“. COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 35, Nr. 4 (04.07.2016): 1460–67. http://dx.doi.org/10.1108/compel-12-2015-0480.

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Purpose – Metamaterials are artificially tailored complex media with extraordinary properties, not available in nature. Due to their unique performance, they are considered as a crucial component of modern radio-frequency technology, especially in the THz regime. However, their lack of wide spectral bandwidths introduce constraints for realistic applications. The purpose of this paper is to propose piezoelectric micro-electromechanical systems (MEMS) actuators to modify the shape of electric field-driven LC (ELC) resonators. A THz modulation capability is revealed by connecting/disconnecting the associated metal parts. Design/methodology/approach – Piezoelectric MEMS actuators are proposed to provide the desired bandwidth enhancement along with THz modulation. Two setups with different degrees of freedom in altering the behaviour of the novel modulator are investigated. A variety of numerical data, acquired via the finite element method, substantiate the advantageous characteristics of the proposed structures. Findings – The novel devices enable the modification of the structural features of an ELC-based complex medium, unveiling in this manner a significant THz modulation capability along with improved bandwidth tunability. Two discrete cases are presented involving different degrees of freedom to shape the overall performance of the metamaterial modulator. Originality/value – Development of a THz modulator, which utilises metamaterials as its fundamental component. Incorporation of tunable piezoelectric metamaterials into THz technology allowing increased reconfigurability. Bandwidth enhancement of metamaterial systems and alternative design via multiple controllable gaps enabling more degrees of freedom for design purposes.

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Khan, Jan Amir, Evan Heller und Faquir Jain. „Characterization of Ge Quantum Dot Optical Waveguides for High Speed Optical Modulators“. International Journal of High Speed Electronics and Systems 27, Nr. 01n02 (März 2018): 1840001. http://dx.doi.org/10.1142/s0129156418400013.

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Quantum Dot (QD) Optical Modulators can provide high speed modulation in low cost indirect bandgap materials. Si based optical modulators can be realized with the inclusion of self-assembled Ge QDs to provide low cost, high speed CMOS compatible optical devices. In this paper, we present the optical characterization of a novel Ge-QD Si-SiO2 based waveguide for use in as an optical modulator. Optical performance figures of merit are investigated including insertion loss (IL) measurements, and Wavelength dependent loss (WDL). We present a multimode waveguide fabricated with conventional CMOS processing. The waveguide provides 4.43dB/cm loss and individual discrete absorption regimes corresponding to the unique minibands produced by superlattice properties of the self-assembled Ge QDs in the IR regime. Absorption properties of the Ge QDs are demonstrated and verified against the QD superlattice bandgap model. Analysis and simulation is presented to qualitatively compare the QD bandgap energies with the reported optical properties. The QD functionalized structure demonstrates the fundamental optical principles of a QD waveguide, setting the foundation for a active modulation testing of this QD based optical modulator.

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Baig, Mirza Uzair, Anders Host-Madsen und Aria Nosratinia. „Discrete Modulation for Interference Mitigation“. IEEE Transactions on Information Theory 66, Nr. 5 (Mai 2020): 3026–39. http://dx.doi.org/10.1109/tit.2019.2953916.

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Blinc, R., A. Gregorovič und B. Zalar. „Deuteron NMR Lineshapes in the Antiferroelectric Liquid Crystalline Phase of MHPOBC“. Zeitschrift für Naturforschung A 55, Nr. 1-2 (01.02.2000): 298–300. http://dx.doi.org/10.1515/zna-2000-1-252.

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The deuteron NMR lineshapes in the tilted antiferroeelectric smectic liquid crystalline phases are evaluated for: i) the case of a discrete short pitch modulation P1 = N • d where N = 2,3,4, ii) for a superposition of two modulations p1 and p0 where p0 ≫p1 as well as iii) for the case where in addition rapid molecular exchange between adjacent layers takes place due to translational diffusion. The results are compared with the experimental deuteron NMR spectra of α-CD2 deuterated MHPOBC in the Sm C*A phase measured at different angles between the magnetic field direction and the normals to the smectic layers. The alternating tilt structure of the Sm C*A phase is confirmed

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Arantes, Gilberto, Luiz S. Martins-Filho und Adrielle C. Santana. „Optimal On-Off Attitude Control for the Brazilian Multimission Platform Satellite“. Mathematical Problems in Engineering 2009 (2009): 1–17. http://dx.doi.org/10.1155/2009/750945.

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This work deals with the analysis and design of a reaction thruster attitude control for the Brazilian Multimission platform satellite. The three-axis attitude control systems are activated in pulse mode. Consequently, a modulation of the torque command is compelling in order to avoid high nonlinear control action. This work considers the Pulse-Width Pulse-Frequency (PWPF) modulator which is composed of a Schmidt trigger, a first-order filter, and a feedback loop. PWPF modulator holds several advantages over classical bang-bang controllers such as close to linear operation, high accuracy, and reduced propellant consumption. The Linear Gaussian Quadratic (LQG) technique is used to synthesize the control law during stabilization mode and the modulator is used to modulate the continuous control signal to discrete one. Numerical simulations are used to analyze the performance of the attitude control. The LQG/PWPF approach achieves good stabilization-mode requirements as disturbances rejection and regulation performance.

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Yan, Shu Mei, und Hui Fang. „Digital Signal Modulation with Recognition Algorithm to Identify the Ability to Optimize the Wavelet“. Advanced Materials Research 1014 (Juli 2014): 413–16. http://dx.doi.org/10.4028/www.scientific.net/amr.1014.413.

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Large errors in the digital signal modulation recognition algorithm for the general wavelet transform, we propose a discrete optimization algorithm based on wavelet transform, which is generally improved algorithm based on wavelet transform algorithm, the original algorithm in order to avoid redundancy Yu phenomenon, discrete variable domain transform operation, the wavelet transform and then use the algorithm to improve the amplitude modulation of digital signals, quadrature amplitude modulated signal, a digital frequency-modulated signal and the digital phase modulated signal is identified. Simulation results show that the discrete wavelet transform algorithm optimization wavelet transform algorithm than the digital signal modulation recognition applications to identify errors in the proposed smaller, more accuracy.

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Dunham, J. „Optimal Discrete-Time Delta Modulation System“. IEEE Transactions on Communications 34, Nr. 5 (Mai 1986): 510–12. http://dx.doi.org/10.1109/tcom.1986.1096557.

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Perilloux, Bruce E. „Discrete thin-film layer thickness modulation“. Applied Optics 37, Nr. 16 (01.06.1998): 3527. http://dx.doi.org/10.1364/ao.37.003527.

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Rymarski, Zbigniew, und Krzysztof Bernacki. „Technical Limits of Passivity-Based Control Gains for a Single-Phase Voltage Source Inverter“. Energies 14, Nr. 15 (28.07.2021): 4560. http://dx.doi.org/10.3390/en14154560.

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Passivity-based control (PBC) seems to be predicted for the control algorithms in the voltage source inverters (VSI) for voltage backup systems. This paper presents limitations of the improved (IPBC) version of the PBC (directly measuring the output voltage) maximum voltage and current gains. In a microprocessor-controlled inverter, these depend on the PWM modulator dynamic properties, the switching frequency, the modulation index value (avoiding modulator saturation and enabling the rapid increase of the filter inductor current), and the parameters of the VSI output filter. A single switching period delay of the digital PWM modulator was considered in the theoretical calculations based on a discrete inverter model. The simulations for the standard nonlinear rectifier RC load enabled the initial adjustment of the IPBC border gains, which depended on the switching frequency. Some small harmonics oscillations of the output voltage were acceptable for the test rectifier RC load or dynamic load. However, oscillations of the inductor current increased the power losses in the coil core. Experimental verification of the simulation results using a laboratory VSI model is also presented.

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Hoxha, Julian, Wael Hosny Fouad Aly, Erdjana Dida, Iva Kertusha und Mouhammad AlAkkoumi. „A Novel Optical-Based Methodology for Improving Nonlinear Fourier Transform“. Mathematics 10, Nr. 23 (29.11.2022): 4513. http://dx.doi.org/10.3390/math10234513.

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The increasing demand for bandwidth and long-haul transmission has led to new methods of signal processing and transmission in optical fiber communication systems. The nonlinear Fourier transform is one of the most recent methods proposed, and is able to represent an integrable nonlinear Schrödinger equation (NLSE) channel in terms of its continuous and discrete spectrum, to overcome the limitation of the bandwidth imposed by the Kerr effect on silica fibers. In this paper, we will propose and investigate the Boffetta-Osburne method for the direct nonlinear Fourier implementation, and the Gel’fand-Levitan-Marchenko equation for the inverse nonlinear Fourier, as only the continuous part of the nonlinear spectrum will be used to encode information. A novel methodology is proposed to improve their numerical implementation with respect to the NLSE, and we analyze in detail how the improved algorithm can be used in a real optical system, by investigating three different modulation schemes. We report increased performance transmission and consistency in the numerical results when the proposed methodology is applied. Our results show that b-modulation will increase the Q-factor by 2 dB with respect to the other two modulations. The improvement results with our proposed methodology suggest that b-modulation applied only to a continuous part of the nonlinear spectrum is a very effective method for maximizing both the transmission bandwidth and distance in optical fiber communication systems.

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Veillon, Matías, Eduardo Espinosa, Pedro Melin, Galina Mirzaeva, Marco Rivera, Carlos R. Baier und Roberto O. Ramirez. „Improved Feedback Quantizer with Discrete Space Vector“. Sensors 24, Nr. 1 (03.01.2024): 287. http://dx.doi.org/10.3390/s24010287.

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The use of advanced modulation and control schemes for power converters, such as a Feedback Quantizer and Predictive Control, is widely studied in the literature. This work focuses on improving the closed-loop modulation scheme called Feedback Quantizer, which is applied to a three-phase voltage source inverter. This scheme has the natural behavior of mitigating harmonics at low frequencies, which are detrimental to electrical equipment such as transformers. This modulation scheme also provides good tracking for the voltage reference at the fundamental frequency. On the other hand, the disadvantage of this scheme is that it has a variable switching frequency, creating a harmonic spectrum in frequency dispersion, and it also needs a small sampling time to obtain good results. The proposed scheme to improve the modulation scheme is based on a Discrete Space Vector with virtual vectors to obtain a better approximation of the optimal vectors for use in the algorithm. The proposal improves the conventional scheme at a high sampling time (200 μs), obtaining a THD less than 2% in the load current, decreases the noise created by the conventional scheme, and provides a fixed switching frequency. Experimental tests demonstrate the correct operation of the proposed scheme.

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Meng, Wenwen, Dongfeng Shi, Wei Yang, Linbin Zha, Yuefeng Zhao und Yingjian Wang. „Multi-Object Positioning and Imaging Based on Single-Pixel Imaging Using Binary Patterns“. Sensors 22, Nr. 9 (22.04.2022): 3211. http://dx.doi.org/10.3390/s22093211.

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Single-pixel imaging (SPI) is a new type of imaging technology that uses a non-scanning single-pixel detector to image objects and has important application prospects and value in many fields. Most of the modulators currently used in SPI systems are digital micromirror device (DMD) modulators, which use a higher frequency for binary modulation than other alternatives. When modulating grayscale information, the modulation frequency is significantly reduced. This paper conducts research on multiple discrete objects in a scene and proposes using binary patterns to locate and image these objects. Compared with the existing methods of using gray patterns to locate and image multiple objects, the method proposed in this paper is more suitable for DMD-type SPI systems and has wider applicability and greater prospects. The principle of the proposed method is introduced, and the effectiveness of the method is experimentally verified. The experimental results show that, compared to traditional SPI methods, the number of patterns required by the proposed method is reduced by more than 85%.

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Guo, Rui, Jiang-Yan Song, Hong-Tao Zhang und Feng-Hua Qi. „Soliton solutions, conservation laws and modulation instability for the discrete coupled modified Korteweg–de Vries equations“. Modern Physics Letters B 32, Nr. 14 (20.05.2018): 1850152. http://dx.doi.org/10.1142/s021798491850152x.

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In this paper, the discrete coupled modified Korteweg–de Vries equations are systematically investigated. Based on the Lax pair, N-fold discrete Darboux transformation, discrete soliton solutions, conservation laws and modulation instability are analyzed and presented.

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Wang, Ziyu, Yinghua Wang, Longlong Wu, Qionghua Wu und Jian Shao. „Dynamic modulation of electromagnetically induced transparency in complementary graphene metamaterial“. AIP Advances 12, Nr. 6 (01.06.2022): 065231. http://dx.doi.org/10.1063/5.0093664.

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In this paper, we use a complementary graphene metamaterial to achieve dynamic modulation of electromagnetically induced transparency. The structure consists of a disk slot graphene and a strip slot graphene corresponding to bright and dark modes, respectively. A clear transparency window appears in the transmission spectrum. In contrast to metallic metamaterials, the transmission spectrum of the complementary graphene metamaterial can be controlled by changing the Fermi energy rather than reconstructing the structure. The complementary graphene metamaterial proposed in this paper modulates the gate voltage more simply than discrete structures of a graphene metamaterial. Active control of the slow-light effect can also be realized by modulating the Fermi energy. This work demonstrates potential applications in the design of terahertz modulators, environmental sensors, and slow-light devices.

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Yang, Wen Jie. „Study on Direct Torque Control of Brushless Doubly-Fed Machine Based on Discete Space Vector Modulation“. Applied Mechanics and Materials 615 (August 2014): 402–8. http://dx.doi.org/10.4028/www.scientific.net/amm.615.402.

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The paper introduces Working mode of brushless doubly-fed machine（BDFM） and mathematical model in the d-q coordinates for BDFM，a strategy of discrete space vector modulation in direct torque control for BDFM has been Proposed 。The paper uses Matlab / Simulink to model and simulate the system of the direct torque control for brush double-fed motor based on discrete Space Vector Modulation.Simulation results prove that the discrete space vector modulation technique can reduce the torque ripple of traditional direct torque control system for BDFM, and improve waveform of current and Flux of Control winding.

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Saxena, Indu. „General technique for discrete retardation-modulation polarimetry“. Applied Optics 32, Nr. 19 (01.07.1993): 3614. http://dx.doi.org/10.1364/ao.32.003614.

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Yuan-Pei Lin und See-May Phoong. „Perfect discrete multitone modulation with optimal transceivers“. IEEE Transactions on Signal Processing 48, Nr. 6 (Juni 2000): 1702–11. http://dx.doi.org/10.1109/78.845928.

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29

Moodie, D. G., M. J. Harlow, M. J. Guy, S. D. Perrin, C. W. Ford und M. J. Robertson. „Discrete electroabsorption modulators with enhanced modulation depth“. Journal of Lightwave Technology 14, Nr. 9 (1996): 2035–43. http://dx.doi.org/10.1109/50.536971.

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Lettington, A. H., und Q. H. Hong. „Measurement of the Discrete Modulation Transfer Function“. Journal of Modern Optics 40, Nr. 2 (Februar 1993): 203–12. http://dx.doi.org/10.1080/09500349314550221.

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31

Zakharchenko, Vladimir, und Sergey Zakharchenko. „Numeric Low-Altitude Altimeter Modeling with Computation of Additional Modulation Frequencies Using a Genetic Algorithm“. Mathematical Physics and Computer Simulation, Nr. 2 (Juli 2021): 18–26. http://dx.doi.org/10.15688/mpcm.jvolsu.2021.2.2.

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This study is concerned with the problem of increasing the accuracy of a low-altitude altimeter employing the frequency modulation principle. A way to suppress the “discrete error” of the altimeter by employing additional frequency modulation of the carrier wave and averaging the resulting counts is considered. The benefit of such approach is simplicity of technical implementation manifesting in minimal changes in the microwave path and the recording device, which needsto run in averaging count mode. This work presents a genetic algorithm for computing the array of additional modulation frequencies which can be used to reduce the mean square of the discrete error given a limited frequency band. Results of error calculations presented are obtained via mathematical modeling of the altimeter’s operation. It is shown that using additional modulation frequencies obtained by the genetic algorithm allows to reduce the average measurement error two times relatively to the linear modulation form without expanding the occupied frequency band.

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Matsuura, Takaya, Shinichiro Yamano, Yui Kuramochi, Toshihiko Sasaki und Masato Koashi. „Refined finite-size analysis of binary-modulation continuous-variable quantum key distribution“. Quantum 7 (29.08.2023): 1095. http://dx.doi.org/10.22331/q-2023-08-29-1095.

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Recent studies showed the finite-size security of binary-modulation CV-QKD protocols against general attacks. However, they gave poor key-rate scaling against transmission distance. Here, we extend the security proof based on complementarity, which is used in the discrete-variable QKD, to the previously developed binary-modulation CV-QKD protocols with the reverse reconciliation under the finite-size regime and obtain large improvements in the key rates. Notably, the key rate in the asymptotic limit scales linearly against the attenuation rate, which is known to be optimal scaling but is not achieved in previous finite-size analyses. This refined security approach may offer full-fledged security proofs for other discrete-modulation CV-QKD protocols.

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GAO, JIE, HAI LI, JIANXIONG WU, LINGYAN LI, ZHIJIE MAI und GUIHUA CHEN. „ELECTROMAGNETICALLY INDUCED QUANTUM LATTICE SOLITON“. Journal of Nonlinear Optical Physics & Materials 21, Nr. 01 (März 2012): 1250011. http://dx.doi.org/10.1142/s0218863512500117.

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An optical atomic discrete system through optical induction is proposed. A theoretical scheme to produce quantum discrete or lattice solitons (QLSs) in the system is presented with the use of the effects of enhanced self-phase modulation and cross-phase modulation through the giant kerr effect in the electromagnetically induced transparency. The power density and the photon flux can be tuned to a very low level by the coupling field and the soliton can propagate with very slow group velocity.

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Yu, Hao, Jiajun Wang und Zhuangzhuang Xin. „Model Predictive Control for PMSM Based on Discrete Space Vector Modulation with RLS Parameter Identification“. Energies 15, Nr. 11 (31.05.2022): 4041. http://dx.doi.org/10.3390/en15114041.

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Model Predictive Control (MPC) based on Discrete Space Vector Modulation (DSVM) has the advantages of simple mathematical model and fast dynamic response. It is widely used in permanent magnet synchronous motor (PMSM). Additionally, the control performance of DSVM-MPC is influenced by the accuracy of motor parameters and the select speed of optimal voltage vector. In order to identify motor parameters accurately, model predictive control for PMSM based on discrete space vector modulation with recursive least squares (RLS) parameter identification is proposed in this paper. Additionally, a method to preselect candidate voltage vectors is proposed to select the optimal voltage vector more quickly. The simulation model of RLS-DSVM-MPC is established to simulate the influence of different parameters on PMSM performance. The simulation results show that model predictive control for PMSM based on discrete space vector modulation with RLS parameter identification has a better control performance than that of without RLS parameter identification.

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Currie, Stephen P., Denis Combes, Nicholas W. Scott, John Simmers und Keith T. Sillar. „A behaviorally related developmental switch in nitrergic modulation of locomotor rhythmogenesis in larval Xenopus tadpoles“. Journal of Neurophysiology 115, Nr. 3 (01.03.2016): 1446–57. http://dx.doi.org/10.1152/jn.00283.2015.

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Locomotor control requires functional flexibility to support an animal's full behavioral repertoire. This flexibility is partly endowed by neuromodulators, allowing neural networks to generate a range of motor output configurations. In hatchling Xenopus tadpoles, before the onset of free-swimming behavior, the gaseous modulator nitric oxide (NO) inhibits locomotor output, shortening swim episodes and decreasing swim cycle frequency. While populations of nitrergic neurons are already present in the tadpole's brain stem at hatching, neurons positive for the NO-synthetic enzyme, NO synthase, subsequently appear in the spinal cord, suggesting additional as yet unidentified roles for NO during larval development. Here, we first describe the expression of locomotor behavior during the animal's change from an early sessile to a later free-swimming lifestyle and then compare the effects of NO throughout tadpole development. We identify a discrete switch in nitrergic modulation from net inhibition to overall excitation, coincident with the transition to free-swimming locomotion. Additionally, we show in isolated brain stem-spinal cord preparations of older larvae that NO's excitatory effects are manifested as an increase in the probability of spontaneous swim episode occurrence, as found previously for the neurotransmitter dopamine, but that these effects are mediated within the brain stem. Moreover, while the effects of NO and dopamine are similar, the two modulators act in parallel rather than NO operating serially by modulating dopaminergic signaling. Finally, NO's activation of neurons in the brain stem also leads to the release of NO in the spinal cord that subsequently contributes to NO's facilitation of swimming.

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Neumann, David L., und Ottmar V. Lipp. „The Independent Effects of Attention and Lead Stimulus Properties on the Acoustic Blink Reflex“. Journal of Psychophysiology 17, Nr. 3 (Januar 2003): 124–34. http://dx.doi.org/10.1027//0269-8803.17.3.124.

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Abstract The effects of attention to a lead stimulus and of its sensory properties on modulation of the acoustic blink reflex were investigated. Participants performed a reaction time task cued by an acoustic or a visual lead stimulus. In Experiment 1, half the participants were presented with sustained lead stimuli. For the remainder, the lead stimulus was discrete and consisted of two brief presentations that marked the onset and offset of a stimulus-free interval. In Experiment 2, sustained lead stimuli were presented at a low or high intensity. The attentional demands of the task enhanced blink latency and magnitude modulation during acoustic and visual lead stimuli, with blink modulation being largest at a late point during the lead stimulus. Independent of the attentional effects, blink latency and magnitude modulation were larger during sustained than during discrete acoustic lead stimuli, whereas there was no difference for visual lead stimuli. Increases in the intensity of the lead stimulus enhanced blink modulation regardless of lead stimulus modality. Attention to a lead stimulus and the properties of the lead stimulus appear to have independent effects on blink reflex modulation.

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Pan, Q., W. C. Chung und K. W. Chow. „The coupled Hirota system as an example displaying discrete breathers: Rogue waves, modulation instability and varying cross-phase modulations“. AIP Advances 8, Nr. 9 (September 2018): 095303. http://dx.doi.org/10.1063/1.5045532.

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38

Mann, James B., Yang Guo, Christopher Saldana, Ho Yeung, W. Dale Compton und Srinivasan Chandrasekar. „Modulation-Assisted Machining: A New Paradigm in Material Removal Processes“. Advanced Materials Research 223 (April 2011): 514–22. http://dx.doi.org/10.4028/www.scientific.net/amr.223.514.

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Modulation Assisted Machining (MAM), based on controlled superimposition of low-frequency modulation to conventional machining, effects discrete chip formation and disrupts the severe contact condition at the tool-chip interface. The underlying theory of discrete chip formation and its implications are briefly described and illustrated. Benefits such as improved chip management and lubrication, reduction of tool wear, enhanced material removal, particulate manufacturing and surface texturing are highlighted using case studies. MAM represents a new paradigm for machining in that it deliberately employs ‘good vibrations’ to enhance machining performance and capability.

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Li, Chen Wu, Jian Zhang, Qin Xie und Xiao Hong Zhang. „Carrier Modulation Technology Based on Orthogonal Frequency Division Multiplexing“. Advanced Materials Research 774-776 (September 2013): 1671–76. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.1671.

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This paper first analyzes the transmission characteristics of low-voltage power line channels with the focus on the study of carrier modulation technology regarding the power line communication part, then proposes the orthogonal frequency division multiplexing technology that serves for the digital communication of family network power line communication gateways, analyzes the OFDM system principle, actulizes OFDM modulation and demodulation through discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT), and build the OFDM simulation model. Finally, a specific plan of using power lines as the family network transmission media is proposed.

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Kivshar, Yuri S., und Michel Peyrard. „Modulational instabilities in discrete lattices“. Physical Review A 46, Nr. 6 (01.09.1992): 3198–205. http://dx.doi.org/10.1103/physreva.46.3198.

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41

Alexey L., Toropov. „A wall-mounted gas convection boiler with an atmospheric burner operating in the double modulation mode“. Stroitel'stvo: nauka i obrazovanie [Construction: Science and Education] 12, Nr. 2 (30.06.2022): 50–61. http://dx.doi.org/10.22227/2305-5502.2022.2.4.

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Introduction. Apartment heating requires the thermal capacity of no more than 1.0–2.5 kW; hot water preparation needs 15–25 kW. Convection gas boilers cannot operate efficiently, if a change in the range of smooth modulation reaches 20 times. Discrete modulation is triggered in the heating mode, which is also accompanied by a substantial increase in greenhouse gas emissions and a sharp decline in energy efficiency. The heating of such premises requires heat generators operating in the two ranges of thermal capacity. Materials and methods. The author analyzes the operation of a wall-mounted convection gas boiler with an atmospheric burner equipped with a three-section manifold that ensures a smooth modulation range of 2.4–6 kW, when the boiler is in the heating mode, and the modulation range of 15–24 kW, when the boiler is in the hot water supply mode (HWS). Results. The author made boiler efficiency diagrams for the heating and HWS modes during the steady boiler operation; the author also made boiler diagrams for discrete modulation modes and the regular on-off switching of the boiler. A direct method, that entailed the study of the flow rates of gas and heat conductor, as well as the boiler inlet and outlet temperatures, was employed to find the energy efficiency values. Conclusions. The use of conventional wall-mounted gas convection boilers as a source of heating for the 60 m2 premises entails discrete capacity modulation, that causes a substantial reduction in the energy efficiency of a heating system and rises greenhouse gas emissions. The application of efficiency indicators to different modes of operation of boilers does not convey the real mode of operation of a boiler during the heating period, since it entails a substantial overestimation, while wall-mounted convection boilers, having atmospheric burners with two ranges of smooth modulation, ensure highly efficient apartment heating.

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Saalfeld, Tobias, Tobias Piwczyk, Ralf Wunderlich und Stefan Heinen. „A digital receiver signal strength detector for multi-standard low-IF receivers“. Advances in Radio Science 16 (04.09.2018): 51–57. http://dx.doi.org/10.5194/ars-16-51-2018.

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Abstract. This paper presents a receiver signal strength detector based on a discrete Fourier transform implementation. The energy detection algorithm has been designed and measured using a custom multi-standard transceiver ASIC with a low-IF receiver at 0.5, 1 and 2 MHz IF. The proposed implementation directly processes the single bit ΔΣ modulator data and features a clear channel assessment for arbitrary modulation schemes without energy consuming demodulation. Continuous monitoring of the derivative of the RSSI takes advantage of faster coefficient convergence for higher power levels and reduces computation time. A dynamic range of 65 dB has been achieved in FPGA based measurements with a linearity error of less than 1.2 dB. Furthermore, synthesis results for an on-chip implementation for an 130 nm RF CMOS technology show an overall power consumption of 1.5 mW during calculation.

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Sumathi, Parasuraman, und Ksh Milan Singh. „Sliding discrete Fourier transform-based mono-component amplitude modulation–frequency modulation signal decomposition“. IET Communications 9, Nr. 9 (11.06.2015): 1221–29. http://dx.doi.org/10.1049/iet-com.2014.0643.

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44

Inan, Beril, S. C. Jeffrey Lee, Sebastian Randel, Ioannis Neokosmidis, Antonius M. J. Koonen und Joachim W. Walewski. „Impact of LED Nonlinearity on Discrete Multitone Modulation“. Journal of Optical Communications and Networking 1, Nr. 5 (18.09.2009): 439. http://dx.doi.org/10.1364/jocn.1.000439.

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Vaidyanathan, P. P., Yuan-Pei Lin, S. Akkarakaran und See-May Phoong. „Discrete multitone modulation with principal component filter banks“. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications 49, Nr. 10 (Oktober 2002): 1397–412. http://dx.doi.org/10.1109/tcsi.2002.803249.

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46

Muller, S., U. Ammann und S. Rees. „New Time-Discrete Modulation Scheme for Matrix Converters“. IEEE Transactions on Industrial Electronics 52, Nr. 6 (Dezember 2005): 1607–15. http://dx.doi.org/10.1109/tie.2005.858713.

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47

Ataullaev, N. O., A. A. Dziaruhina und K. S. Murodov. „Static Characteristics of Magnetic Modulation DC Converters with Analog Filter“. Science & Technique 22, Nr. 5 (11.10.2023): 428–32. http://dx.doi.org/10.21122/2227-1031-2023-22-5-428-432.

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The paper examines the most important requirements for current converters, the features of magnetic modulation converters, and identifies their fundamental and design features. The paper considers the principle of constructing converters for contactless DC measurement and their disadvantages of converters, methods of current measurement using magnetic modulation current converters, in which the magnetic permeability of a core made of ferromagnetic material is modulated. The influence of the parameters of the elements of a magnetic modulation current converter with an analog filter on their static characteristics and the influence of modulation on the static characteristics of the sensor have been determined. It has been revealed that the discrete operation of the magneto-modulation DC converter does not affect its static characteristics and the nonlinearity due to the type of modulation also does not affect the static characteristics of the sensor. The most important requirement for the operation of a magneto-modulation DC converter for autonomous power supplies with recharging buffer batteries is the formation of a static characteristic with the specified properties: linearity, sensitivity and the required range of operating currents. An analytical expression for the static characteristic is obtained in the form of the dependence of the output voltage on the values of T1 and T2 for the basic version of a magnetic modulation DC converter with an analog low-pass filter. Curves of the static characteristics of the magneto-modulation DC converter have been constructed for different values of the resistance of the ballast resistor R, as well as curves of the static characteristics of the magneto-modulation DC converter for different values of the supply voltage E. Analytical expressions for the static characteristics of a magneto-modulation DC converter based on magnetic transistor multivibrators with pulse-width modulation, curves of their characteristics and the output voltage of a magnetic modulation DC converter with a digital output and a discrete filter have been obtained.

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García, A. G., M. A. Hernández-Medina und G. Pérez-Villalón. „Filter banks on discrete abelian groups“. International Journal of Wavelets, Multiresolution and Information Processing 16, Nr. 04 (Juli 2018): 1850029. http://dx.doi.org/10.1142/s0219691318500297.

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In this work, we provide polyphase, modulation, and frame theoretical analyses of a filter bank on a discrete abelian group. Thus, multi-dimensional or cyclic filter banks as well as filter banks for signals in [Formula: see text] or [Formula: see text] spaces are studied in a unified way. We obtain perfect reconstruction conditions and the corresponding frame bounds in this particular context.

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Rahim Mammadzada, Kamala Alieva, Rahim Mammadzada, Kamala Alieva. „MODULATION FOR INFORMATION MEASUREMENT SYSTEM IN CONTEXT OF SOFTWARE DEVELOPMENT USING NODE-BASED GRAPHICAL EDITOR“. PIRETC-Proceeding of The International Research Education & Training Centre 24, Nr. 03 (14.05.2023): 143–51. http://dx.doi.org/10.36962/piretc24032023-143.

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In this paper information measurement system (IMS) modulation integrated with a graphical node editor (GNE) is carried out for engineering applications to build software capable of both editing and simulating different scenarios. A modulation characteristic measuring and classification system for classifying a discreet signal that includes a preprocessor, stage measuring system and modulation classifier. Preprocessor detects impulse begins and finishes, determines impulse time, and changes the discreet signal into digital signals. The stage measuring system determines short chip counts, long chip counts, stage jump magnitudes, number of stage states, and polynomial coefficients for stage modulation of the discreet signal. Modulation classifier identifies modulation type on base of measurements using both rules-based and similarity-based classification methods. The lack of educational-oriented software in the IMS field leads to a more challenging learning curve resulting in a drop in student motivation. Software integrated with GNE is purposed to minimize the overwhelming feeling in students in the IMS field by simultaneously providing understandable execution order for the machine. An application consisting of GNE with the addition of custom node architecture and their interaction logic is built to conduct laboratory work using this software. Executed laboratory work result shows that having GNE integrated into the software can significantly impact visual understanding, leading to higher motivation and interest in the subject in students. Keywords: Node, Graphical Editor, GPIOS, Information measurement system.

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Karimov, Timur, Vyacheslav Rybin, Georgii Kolev, Ekaterina Rodionova und Denis Butusov. „Chaotic Communication System with Symmetry-Based Modulation“. Applied Sciences 11, Nr. 8 (20.04.2021): 3698. http://dx.doi.org/10.3390/app11083698.

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Communication systems based on chaotic synchronization are gaining interest in the area of secure and covert data transmission. In this paper, a novel digital communication technique based on a coherent chaotic data transmission approach is proposed. In general, this technique resembles the well-known approach based on the modulation of nonlinearity parameters. The key idea of this study is to modulate a signal by varying not the system parameter but the symmetry coefficient in discrete chaotic models obtained by the special numerical integration method. For this purpose, the self-adjoint semi-implicit integration method of order 2 is used to obtain discrete master and slave models of the considered chaotic oscillator. The experimental results explicitly show that, like during parameter modulation, transmitting and receiving oscillators may completely synchronize only if the symmetry coefficients are equal in both systems. The architecture of the communication system based on the proposed modulation is presented. The practical applicability of the approach is confirmed by transmitting a test binary sequence between the transmitter and receiver models and preliminary benchmarking of the obtained communication system. Since the symmetry coefficient modulation does not significantly impact the chaotic behavior of the transmitting digital system, its better suitability for covert messaging was experimentally confirmed by comparing it with the parameter modulation technique.

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