Showing 31 results for Amp
A. Hamidi, S. Karimi, A. Ahmadi,
Volume 19, Issue 2 (6-2023)
Abstract
One of the problems in digital control of power converters is calculation time in each sampling instant which effect on cost and complexity of digital controller. In this paper, a formula is introduced for calculating the number of clock cycles in each sample then interaction between sampling frequency and implementation cost (number of functional units and word length) of FPGA-based digital controller of DC-AC converter (three-phase four-legs inverter) is verified. The digital architecture is built on finite set model predictive control, and implemented on the FPGA board based on fixed-point calculations. We consider two digital architectures for design the controller in this study. One with four functional units and another with six functional units. This study aims to develop a mathematical equation for the number of clock cycles in each time instant to select the best switching state in the control algorithm, which affects the sampling frequency and clock frequency. Based on the obtained results, the number of functional units, word-length, and the number of switches determine the maximum clock cycles. By knowing maximum clock cycles the maximum sampling frequency is determined. In structure with four functional units, the maximum sampling frequency is 71 kHz for WL=8 bits and 17.7 kHz for WL=32 bits, and in structure, with six functional units, the maximum sampling frequencies are 97.6 and 24.4 kHz for WL=8 and WL=32 bits, respectively. In architecture with more functional units, we have greater sampling frequency with more accuracy and cost. The results obtained from this paper can be a reference for digital controller design.
S. Tidjani, Z. Hammoudi,
Volume 19, Issue 2 (6-2023)
Abstract
This paper describes a spectrum observatory (SO) performed outdoor in two locations in Algeria and highlights the importance of the SO in the improvement
of spectrum management in cognitive radio networks. These measurements were achieved in conjunction with the ANF (Agence Nationale des Fréquences), between January and February 2020. It surveys second, third, and fourth-generation mobile networks and DVB-T frequency bands. A comparative study of two measurement campaigns (in urban & rural) that were carried out via identical setup and equipment is presented. Some major short-duration measurement campaigns are cited and summarized for the state-of-the-art. Additionally, Different statistics are imputed and 3D graphics of the spectrum occupancy are plotted to highlight the spectrum opportunities in this region. This work aims to analyze the radio environment in Algeria and identify frequency bands that could be invested for the integration of new wireless systems and Cognitive Radio opportunistic networks. The evaluation of measurement results reveals low resource occupation, lower than 30.27%, for Constantine and 8.43% for Ouargla. The final part of the study inspects the effect of specific SO features upon the management strategy parameters’ selection. Via a meaningful SO, an efficient spectrum management strategy can achieve the safest users access to the idlest channels with the minimum costs and risks.
B. Dorostkar Yaghouti,
Volume 19, Issue 2 (6-2023)
Abstract
By increasing the transceiver devices within the 3.1 to 10.6 GHz frequency band, the interferers and strong blockers from different equipment degraded the main received signals, so linearity performance becomes more notable. In this paper, a two-path low noise amplifier (LNA) is proposed for satisfying the overall efficiency of the Ultra-wideband (UWB) radar used in vital sign detection, precise indoor localization, and high data rate wireless communications. A novel high linear circuit is recommended based on Complementary Derivative Superposition (CDS) and Post Distortion (PD) techniques. High pass filter and inductive source degeneration structured input impedance matching. Post layout results of the designed UWB-LNA in 180-nm CMOS represented the average of third-order Intercept Point (IIP3) is 8.1 dBm, S21 is 11 dB and, S11 is below -10 dB. The minimum noise figure (NF) is 3.11 dB. The circuit draws 12.7 mA at 1.4-V. The chip area is 930 µm × 1090 µm. The proposed design in this work exhibits higher FOM compared to similar LNAs, It is clear, high-linearity performance in total bandwidth is an advantage compared to recent articles.
E. Y. Burkin, F. A. Gubarev, V. V. Sviridov, D. V. Shiyanov,
Volume 19, Issue 3 (9-2023)
Abstract
A two-channel pulsed power supply for an imaging system with brightness amplification and independent synchronous laser illumination is designed. The power supply generates synchronized high-voltage pulses with a frequency of 16–24 kHz, an average electrical power of up to 1.2 kW, and an adjustable amplitude of up to 6.2 kV to pump copper bromide gas discharge tubes with independent control of the temperature parameters of the active medium. To generate pumping pulses for laser media, we used a two-channel thyratron circuit with a common source of stabilized voltage provided by a step-down pulse stabilizer and a bridge inverter-based circuit for the pulsed charge of storage capacitors. The voltage equalization on the storage capacitors is carried out by means of magnetic coupling of the charging inductances wound on a common core. Adjustable delay lines based on variable inductances provide synchronous operation of two brightness amplifiers with a synchronization accuracy of lasing pulses of ±1 ns. The power supply demonstrated stable operation with two gas discharge tubes having different characteristics, including those with different types of electrodes. It has been integrated into a laboratory facility for the study of high-energy materials combustion.
Godday Biowei, Sulaiman Adeniyi Adekola, Kamoli Akinwale Amusa,
Volume 20, Issue 3 (9-2024)
Abstract
Presented in this paper is an evaluation of human tissue penetration by millimeter wave (mmW) energy, particularly at 30, 35, 40 and 45 GHz. Numerical simulations show that the penetration depths in the tissue are (0.1000, 0.0937, 0.08869 and 0.08882) mm at the aforementioned frequency, respectively. It is also demonstrated that all mmW at those frequencies attenuate to zero at the epidermis which is the layer adjacent to the skin surface, without getting into the dermis which is the next layer. Crucially, these discoveries present fresh, previously unmentioned data within the current research literature. Furthermore, at the lower frequency of 24 GHz, computer simulations presented show that the propagating wave penetrates deeper (depth of 0.12 mm) and attenuates to zero at the dermis. This shows that the depth of penetration increases further at lower frequencies which strongly conforms to the principles of physical reasoning, thereby bolstering the reliability of the findings presented in this paper. The results collectively indicate that the absorption of mmW into the human tissue have limited significance when assessing compliance with electromagnetic field standards at mmW frequencies. It is reinforced in this paper why the human skin reduces the harmful effects of ultra-violet radiation. To lend credence to our formulation, certain aspects of the results obtained in this investigation when compared with similar results in the literature, show good agreements.
Elahe Moradi,
Volume 20, Issue 4 (11-2024)
Abstract
With the intricate interplay between clinical and pathological data in coronary heart disease (CHD) diagnosis, there is a growing interest among researchers and healthcare providers in developing more accurate and reliable predictive methods. In this paper, we propose a new method entitled the robust artificial neural network classifier (RANNC) technique for the prediction of CHD. The dataset CHD in this paper has imbalanced data, and in addition, it has some outlier values. The dataset consists of information related to 4240 samples with 16 attributes. Due to the presence of outliers, a robust method has been used to scale the dataset. On the other hand, due to the imbalance of CHD data, three data balancing methods, including Random Over Sampling (ROS), Synthetic Minority Over Sampling Technique (SMOTE), and Adaptive Synthetic Sampling (ADASYN) approaches, have been applied to the CHD data set. Also, six artificial intelligence algorithms, including LRC, DTC, RFC, KNNC, SVC, and ANN, have been evaluated on the considered dataset with criteria such as precision, accuracy, recall, F1-score, and MCC. The RANNC, leveraging ADASYN to address data imbalance and outliers, significantly improved CHD diagnostic accuracy and the reliability of healthcare predictive models. It outperformed other artificial intelligence methods, achieving precision, accuracy, recall, F1-score, and MCC scores of 95.57%, 96.90%, 99.70%, 97.59%, and 93.42%, respectively.
Mohamed Hussien Moharam, Aya W. Wafik,
Volume 20, Issue 4 (11-2024)
Abstract
High peak-to-average power ratio (PAPR) has been a major drawback of Filter bank Multicarrier (FBMC) in the 5G system. This research aims to calculate the PAPR reduction associated with the FBMC system. This research uses four techniques to reduce PAPR. They are classical tone reservation (TR). It combines tone reservation with sliding window (SW-TR). It also combines them with active constellation extension (TRACE) and with deep learning (TR-Net). TR-net decreases the greatest PAPR reduction by around 8.6 dB compared to the original value. This work significantly advances PAPR reduction in FBMC systems by proposing three hybrid methods, emphasizing the deep learning-based TRNet technique as a groundbreaking solution for efficient, distortion-free signal processing.
Nabiollah Ramezani, Mohsen Shahnazdoost Kilvaei,
Volume 21, Issue 1 (3-2025)
Abstract
In this paper, a novel method is presented that can accurately estimate the Thevenin equivalent circuit parameters of an external power system by RTUs. The presented method is based on the simultaneous measurements of the desired points in the boundary system, which includes the bus voltage amplitude, the current amplitude of the boundary transmission lines, as well as active and reactive power, and is continuously active until the Thevenin equivalent circuit model would be available online. The practical application of the proposed method is related to online monitoring and control of wide-area power systems as well as their development design. Also, the innovation of the method is the accurate estimation of the Thevenin equivalent circuit model from part of the power network where information is not available. In the proposed method, an additional measurement and the least squares method are used to eliminate measurement errors in order to accurately estimate the parameters of the equivalent circuit model. In order to avoid providing the wrong equivalent circuit model due to external system changes, a method is presented that can track the correct system changes to continuously monitor the disturbances. The proposed method performance has been implemented and validated by DigSILENT software.
Gholamreza Khademevatan, Ali Jalali,
Volume 21, Issue 3 (8-2025)
Abstract
A novel simplified EKV model base analog/RF CMOS design pre-SPICE tool is presented in this paper. Addition to facilitating the sizing process, this CAD tool can also optimize circuit characteristics. By having a web address, users can access it without installing any software. Using a graphical and a numerical view, the designer can select degrees of freedom and observe the MOS circuit performance. Through the use of charts versus IC, the graphical view can show tradeoffs in circuit performance in real-time. Charts can be displayed simultaneously in both linear and logarithmic scales. IC CRIT , is also available and can be displayed on the charts. This tool is not limited to one process and it is possible to select different processes. It is efficient for pre-SPICE designs, enhancing intuitive understanding and the designer's experience for future projects while eliminating the need for trial-and-error simulations. Furthermore, the predicted results align well with simulation outcomes, demonstrating the effectiveness of the design and optimization method presented. Two methodologies for selecting optimum ICs are presented by this tool. These are illustrated by the study of linearity indices, AIP3 and IIP3, in one-stage and two-stage differential amplifiers and the design of a single-ended OTA.
Zahra Emami, Abolfazl Halvaei Niasar,
Volume 21, Issue 3 (8-2025)
Abstract
Multiphase electric motors are useful for industrial and military applications that need high power, fault tolerance control, smooth torque, and the ability to share power and torque compared to conventional three-phase electric motors. One type of Multiphase electric machine is Brushless DC Motors (BLDCM) which uses conventional strategies such as hysteresis current controllers. It has important challenges such as high torque ripple, low efficiency, vibrations, and noise that are undesirable for high power applications such as submarines. This paper proposes a new finite control set model predictive control (FCS-MPC) approach with reduction of computational for diode-clamped three-level (DC3L) inverter fed to dual three-phase BLDCM (DTP-BLDCM) by selecting optimal vectors to solve the above problems. Also, an approach of balancing the voltage of the capacitors in two of the DC3L inverters to reduce torque ripple has been proposed. The results of the suggested MPC method are contrasted and verified with the multiband hysteresis current (MHC) method through simulation. The simulation results specify that the suggested MPC controller works superior than the MHC controller. Also, due to the simplicity and low complexity of the suggested MPC strategy used, the real implementation possibility and performance of the controller are checked by simulations for a 4125-V/2.7-MW/350-RPM DTP-BLDCM.
M.e. S.m Mehzabeen , Phd R Gayathri, Pattunnarajam Paramasaivam , Phd Ramya A,
Volume 21, Issue 4 (11-2025)
Abstract
Hepatitis C virus (HCV) detection is a critical aspect of early intervention and effective management of the disease. This paper presents a comprehensive study focused on enhancing the detection accuracy of HCV through the integration of advanced techniques - SMOTE, Optuna, and SHAP - alongside extensive exploratory data analysis (EDA). The study addresses class imbalance using Synthetic Minority Over-sampling Technique (SMOTE), optimizes model performance with Optuna for hyperparameter tuning, and provides model interpretability using SHAP (SHapley Additive exPlanations). EDA is leveraged to gain valuable insights into the dataset's characteristics, ensuring robust data preprocessing and feature engineering. The results show 97% improved HCV detection performance, highlighting the efficacy of the proposed methodology in medical diagnostics and aiding healthcare professionals in making informed clinical decisions.
