Parameters Of Amplifier Research Articles

Switching-mode audio amplifier based on a ΔΣ A/D converter

The article describes the design and implementation of a modular hardware platform intended for testing and measuring various configurations of switching-mode audio amplifiers based on sigma-delta modulation. Two single-channel power amplifier modules were designed and manufactured, along with a stereophonic module serving as the basic source of modulated signals. Additionally, measurements were conducted on the fundamental parameters of the completed amplifier, such as harmonic distortion level, dynamic range, and output power. The developed platform serves as a foundation for modifications and further advancement in the technology of building switching-mode audio amplifiers.

Reduce the effect of the nonlinear distortion in 16-APSK OFDM system by pilot-based automatic phase shift

The paper proposed a method to reduce the effect of nonlinear distortion in 16-APSK OFDM system, which is a pilot-based automatic phase shift at the receiver. Transmitted pilot is inserted during the OFDM modulation process in the transmitter. When the pilot passes through the HPA, information about the nonlinear distortion of the HPA will be carried. In the receiver, the phase angle is rotated automatically based on the phase difference between the received pilots and the transmitted pilots, without depending on the HPA amplifier or system parameters. When the OFDM system uses the APS-pilot method, the nonlinear distortion reduction performance is approximately the same as in the OAPS method, the empirical formula to calculate OAPS, as well as the preset of OAPS manually at the receiver, is not needed.

Operation of colpitts oscillator based on wide band gap operational amplifiers

ABSTRACT The present work is concerned with studying and analysing the operation of the Colpitts oscillator based on operational amplifier with different technologies. During the study, two different operational amplifier types, TLV2374IEN and TL084ACN were used. First, the different operational amplifier parameters including; input offset voltage, input bias current, offset current, voltage gain, input impedance, and output impedance, as well slew rate were measured. Second, the effect of oscillator circuit inductance values (L) on the circuit parameters including; quality factor, signal frequency, inductor impedance, oscillator output impedance, amplification factor and output voltage gain were investigated, whenever the two proposed operational amplifiers were used. The quality factor, signal frequency, inductor impedance, and oscillator output impedance were observed to be affected by L variation. While, both the attenuation and amplification factors were shown to be affected by L till the value of around 860 µH, after this value a semi-saturation for the parameter values wasobserved.

Local and global optimization methods for optical line control based on quality of transmission

The ever-increasing demand for data traffic in recent decades has pushed network operators to give importance to the aspect of infrastructure control to facilitate its scalability and maximize its capacity. A generic lightpath (LP) is deployed starting from a traffic request between a given pair of nodes in a network. LPs are operated in the network based on an estimate of the quality of transmission (QoT), which is derived from the physical layer characteristics of a selected route. Regardless of the model used to estimate QoT, it is necessary to calibrate the model to maximize its accuracy and define minimum design margins. The model calibration process depends significantly on the type of data that can be collected in the field (i.e., type of metric, resolution) and therefore on the available monitoring devices. In this work, a systematic evaluation of the QoT estimation is carried out on a multi-span erbium-doped-fiber-amplified optical line system (OLS) using in the first case only total power monitors and in the second experimentally emulating optical channel monitors (OCMs). Given the type of monitoring devices available, three different physical models are calibrated, and six optimization methods are used to define the optimal configuration of the target gain and tilt parameters of the optical amplifiers, jointly optimizing the working point of all amplifiers (global approach) or proceeding span by span (local approach). Subsequently, the OLS was set in each configuration obtained, and the generalized signal-to-noise ratio (GSNR) profile was measured at the end.

Increasing the accuracy of electrostatic fields strength measurement by using an improved differential transimpedance amplifier circuit

An electrostatic field mill (EFM) is widely used to measure the strength of electrostatic fields, the main drawback of which is the occurrence of large measurement errors (up to 15 % in the range from 0 to 1 kV/m). This paper examines the aspects of using transimpedance amplifiers (TIAs) for the tasks of converting the current received from the EFM sensor into voltage, which will make it possible to reduce the instrumental error and ensure the linearity of the atmospheric electrostatic field strength measurement. In the general case, for the functional circuits of the electrostatic field mill, which include a differential transimpedance amplifier, there is the use of two TIA circuits, which are connected in parallel. Despite the simplicity of implementation, such a configuration contains a number of disadvantages and is not optimal. In the paper, a comparative analysis of a typical circuit of a differential TIA and a circuit of an ungrounded differential transimpedance amplifier with zero voltage drop proposed by the authors is carried out. As a result of the analysis, it was established that the designed authentic circuit of the ungrounded differential transimpedance amplifier with zero voltage drop has better parameters of linearity and interference resistance, in contrast to the generally accepted one. The value of the signal-to-noise ratio for the proposed scheme improved by 42 % on average compared to the typical one. The main difference of the proposed scheme is that the stability of the amplification factor is ensured, the influence of the bias parameters of the operational amplifier is leveled, and the overall noise level is reduced. The use of the designed scheme of an ungrounded differential transimpedance amplifier with zero voltage drop could make it possible to increase the accuracy of the measurement of the electrostatic field strength

A low-power low-noise amplifier with high CMRR for wearable healthcare applications

Low-noise and low-power operation are important parameters of amplifier intended for wearable healthcare applications. However, along with these parameters the amplifier must be able to deliver high Common Mode Rejection Ratio (CMRR) for mitigating the effect of 50/60 Hz interference. This paper reports capacitively coupled-capacitive feedback amplifier based on Self Cascode Current Mirror-II (SCCM-II) Operational Transconductance Amplifier (OTA). The obtained results for proposed SCCM-II OTA based amplifier shows gain of 39.79 dB, input referred noise of 2.64 μVrms, bandwidth of 0.794-343.4 Hz, area consumption of 0.154 μm2, power consumption of 2.54 μW with ±0.9 V supply. The noise efficiency factor and CMRR values for proposed amplifier are 3.87 and 122.1 dB, respectively. In-depth theoretical interpretations and mathematical modeling of amplifier are validated in 0.18μm standard CMOS process using BSIM3V3 MOS device models. The Gaussian distribution plots of proposed amplifier for 200 Monte-Carlo iterations infer mean values for gain and CMRR are 39.79 dB and 112.96 dB which are very close to their nominal values. The proposed amplifier has been compared with conventional approach as well as with literature and improvement in results is observed in terms of input referred noise, power and CMMR. These advantages of the proposed amplifier make it suitable for non-invasive wearable healthcare applications.

Gain flattened S+C+L-band bidirectional thulium doped fiber/multi-section fiber optical parametric hybrid amplifier

This article demonstrates the achievement of optical amplification across the S, C, and L-bands. A hybrid amplifier is proposed that utilizes a combination of bidirectional thulium-doped fiber amplifier (TDFA) and multi-section fiber optical parametric amplifier. With careful selection of TDFA and parametric amplifier parameters, gain can be achieved over complementary bandwidth regions. Resultantly, better gain flatness is achieved over the whole effective bandwidth of 170 nm. The amplifier being proposed is evaluated for a system consisting of 18 wavelength division multiplexed channels, each with a capacity of 100 Gb/s, and a channel spacing of 10 nm. By setting the input power per channel to an optimal value of –30 dBm, the parameters are adjusted to attain a flat gain exceeding 23.52 dB, accompanied by a gain ripple of only 2.09 dB. These parameters are optimized over a wavelength range between 1460 nm and 1630 nm.

Experimental Characterization of Separate Absorption–Multiplication GaAs Staircase Avalanche Photodiodes under Continuous Laser Light Reveals Periodic Oscillations at High Gains

In this work, we experimentally analyze the periodic oscillations that take place in staircase APDs with separate absorption and multiplication regions when operating under continuous laser light. These oscillations increase in frequency when the APD gain increases. We have verified that they are not affected by the parameters (gain and bandwidth) of the transimpedance amplifier, and thus originate inside the APD. The phenomenon is analyzed systematically by considering devices with different thicknesses of the absorption region. Possible physical interpretations related to the flux of holes generated by impact ionization are provided.

Power Amplifier Design for Ultrasound Applications.

A design analysis of the power amplifiers developed for ultrasound applications was conducted because ultrasound applications require different types of power amplifiers, which are one of the most critical electronic components in ultrasound systems. To generate acoustic signals using transducers, which are among the most important mechanical devices in ultrasound systems, an appropriate output voltage, current, or power signal must be produced by a power amplifier. Therefore, an appropriate design analysis of the power amplifier must be conducted to obtain the optimal performance from a transducer. In addition, because of new ultrasound research trends, such as ultrasound systems with other imaging modalities and wireless ultrasound systems, the selection of an appropriate power amplifier could improve the performance of an ultrasound system with other imaging and therapy modalities. This paper describes the design parameters of a power amplifier, including the gain, bandwidth, harmonic distortion, and efficiency. Each power amplifier has specific applications and limitations. Therefore, this review will assist design engineers and ultrasound researchers who need to develop or use power amplifiers in ultrasound applications.

Cable Capacity and Cost/Bit Modeling of Submarine MCF Systems With MC-EDFA Alternatives

We model and examine various amplification options for trans-oceanic repeatered submarine systems using multicore fiber (MCF) transmission in the context of relative cable capacity and relative system cost/bit. First, we compare the optical performance of various configurations of parallel standard single-core erbium-doped fiber amplifiers (SC-EDFAs) and multicore erbium-doped fiber amplifiers (MC-EDFAs), including both the C/L-bands and core/cladding pump designs. Key amplifier parameters governing expected capacity and cost/bit performance include noise figure, amplifier bandwidth, relative electrical-to-optical conversion efficiency, and relative amplifier cost. We make our best estimates of these parameters through modeling, analysis, and component cost estimates and assess the sensitivity of the results to the nominal values. We find that MC-EDFAs using either core- or cladding-pumping might offer lower cost/bit than parallel SC-EDFAs but cladding-pumping may reduce cable capacities due to the higher noise figure and potentially smaller amplifier bandwidth.

Two proposed BiCMOS inverters with enhanced performance

The BiCMOS technology finds wide applications when driving heavy loads such as those associated with off-chip loads or long runs within the chip. In this paper, two novel BiCMOS inverters that depend on using Darlington BJT pairs are presented. Also, the operation of the two proposed BiCMOS inverters as amplifiers is discussed. We present closed-form analytical expressions for the low-to-high propagation delay, the high-to-low propagation delay, and the inverter-based amplifier parameters such as the gain and bandwidth under arbitrary load capacitance and transistors’ parameters. The operation of these two inverters is verified by simulation using the 45 nm CMOS predictive-technology model (PTM) with a power supply voltage, VDD, equal to 1 V. The proposed inverters show superior performance compared with the CMOS inverter, the conventional R-circuit BiCMOS inverter, and the full-swing CMOS/bipolar inverter when driving heavy loads even at low supply voltages.

Fiber-Coupled Diamond Magnetometry with an Unshielded Sensitivity of 30pT/Hz

Ensembles of nitrogen-vacancy centers (NVCs) in diamond can be employed for sensitive magnetometry. In this work, we present a fiber-coupled NVC magnetometer with an unshielded sensitivity of $(30\ifmmode\pm\else\textpm\fi{}10)\phantom{\rule{0.2em}{0ex}}\mathrm{pT}/\sqrt{\mathrm{Hz}}$ in a (10--500)-Hz frequency range. This sensitivity is enabled by a relatively high green-to-red photon conversion efficiency, the use of a [100] bias-field alignment, microwave and lock-in amplifier (LIA) parameter optimization, as well as a balanced hyperfine-excitation scheme. Furthermore, a silicon carbide ($\mathrm{SiC}$) heat spreader is used for microwave delivery, alongside low-strain 1-${\mathrm{mm}}^{3}{\phantom{\rule{0.2em}{0ex}}}^{12}$$\mathrm{C}$ diamonds, one of which is placed in a second magnetically insensitive fluorescence-collecting sensor head for common-mode noise cancellation. The magnetometer is capable of detecting signals from sources such as a vacuum pump up to 2 m away, with some orientation dependence but no complete dead zones, demonstrating its potential for use in remote-sensing applications.

Adjustment of the axial load on the bit when hole deepening by using the screw mechanism

The object of the research is a screw mechanism for adjusting the axial load on the bit during a hole deepening. Mathematical modeling of dynamic processes that occur in the drill string during the hole deepening in deep wells is considered. It is shown that in the process of hole deepening, the longitudinal oscillations are proportional in their intensity to the torsional ones. Obtained boundary conditions for mathematical models of the column with the use of a shock absorber or a screw amplifier. In the course of research, it was found that the screw working mechanism of the axial load creates a relationship between the axial load on the bit and the torque on the screw. This makes it possible to install safety devices that limit the torque of the drive shaft (reciprocating engine, rotor). It is shown that various types of energy supplied to the punch, which are transformed by the punching motor and amplified due to the axial (screw) amplifier installed above the bit, ensure the rotary-progressive movement of the ball bit and increase the drilling performance. It was determined that the obtained dependencies take into account the change in time of the axial load and torque depending on the parameters of the axial amplifier and the geological and technical conditions of drilling and the arrangement of the bottom of the drill string. The research results will be useful to scientists and specialists of the oil and gas industry during the physical modeling of the processes of adjusting the axial load on the bit during a hole deepening by using a screw mechanism.

Enhanced phase sensitive amplification towards improving noise immunity

Quantum states are essential resource for quantum-enhanced applications. Loss incurred in the distribution channel, however, dissipates the high signal-to-noise ratio advantage enjoyed by the squeezed state. Here, we first demonstrate noise immunity enhancement by using phase-sensitive amplifier (PSA) with measurement-based noiseless linear amplifier (MB-NLA). We explore the signal transfer capability with the amplifier in a noisy channel. The MB-NLA enhanced PSA has obvious suppression effect on channel noises, especially it has improvement for the noise contaminated signal. Better performance can be achieved by flexibly adjusting amplifier parameters. With the amplifier, it is promising to overcome the entanglement-distribution loss and show its superiority in squeezing based quantum sensing.

Dynamic Behavior and Stability Analysis of Automatic Voltage Regulator with Parameter Uncertainty

This research article describes a novel optimization technique called simulink design optimization (SDO) to compute the optimal PID coefficients for an automatic voltage regulator (AVR). The time-domain performance of the proposed controller was analyzed using MATLAB/Simulation, and its performance was compared with that of water cycle algorithm, genetic algorithm, and local unimodal sampling algorithm-based PID controllers. The robustness of the proposed controller was verified by applying the disturbances to the generator field voltage and the amplifier parameter uncertainty. The studies presented in literature were discussed the AVR loop stability using the Bode plot which will not give the minimum stability margins. This study proposes a novel stability analysis called disk-based stability analysis to authenticate the stability of the AVR loop which is obtained by the classical analysis. This stability was compared with the proposed stability analysis. The MATLAB results reveal that the SDO-PID controller regulates the terminal voltage of the generator precisely, is more robust to parameter uncertainty, and is more stable than the other controllers. The maximum allowable parameter uncertainty of the amplifier model was identified as 102% of its nominal parameters. The stability margins are recognized as DGM = 10.40 dB and DPM = 56.50° for the AVR stability.

Unapređenje pneumo-hidrauličkog pojačala za mašine za presovanje - projektovanje i proračun parametara

Pneumohydraulic pressure amplifiers are widely used in mechanical engineering. Using a pneumohydraulic amplifier makes it possible to minimize the size of the presses while simultaneously multiplying their technological effort. A significant disadvantage of the classical method of force multiplication is the low speed of movement of the working bodies of technological equipment under a hydraulic drive. The article proposes a fundamentally new design of a pneumohydraulic amplifier, in which a high-speed pneumatic cylinder carries out the idling of the technological tool, and force multiplication is carried out only at the stage of the working stroke, which allows many times to increase the performance of the amplifier. This effect is achieved by using a movable hydraulic chamber. The engineering formulas and diagrams presented in the article for calculating the parameters of a new pneumohydraulic amplifier allow engineers to adapt the amplifier to various technological conditions. The economic effect when using the proposed amplifier design is achieved by multiplying the productivity of the press equipment.

ПРОСТИЙ МЕТОД ПІДВИЩЕННЯ ВИСОКОЧАСТОТНОЇ ПОЗАСМУГОВОЇ СТАБІЛЬНОСТІ РАДІОЧАСТОТНИХ ПІДСИЛЮВАЧІВ

Subject and Purpose. Methods for determining and ensuring the stability of radio frequency (RF) amplifiers have been progressing quite actively over the past decades. However, most of them are not convenient for practical use. Combining analytical and graphical techniques widely accepted at the moment requires a highly skillful user and licensed software. Also, a bad point is the lack of clear algorithms for increasing the out-of-band high-frequency stability of amplifiers, sending us to the procedure of successive approx- imations when an optimal solution for an individual scheme is sought. The present work seeks for a simple method that effectively increases the out-of-band high-frequency stability of RF amplifiers and improves the reliability of signal amplification systems, espe- cially those complex structures that incorporate low-frequency radio telescopes. Methods and Methodology. The parameters of the RF amplifiers and passive circuits are obtained by computer modeling upon the S-parameters given by the manufacturer. The amplifier stability is determined by the K-factor for stability. Results. A simple universal method has been developed to improve the out-of-band high-frequency stability of RF amplifiers. In this method, a stabilization RstabLstab circuit is connected to the amplifier in series with the load. An original procedure has been designed to calculate the stabilization circuit. Also, a metric has been proposed that evaluates the practical margins of the out-of-band high-frequency stability of RF amplifiers and makes it possible to compare them one to another. Finally, the proposed method offers freedom from the licensed software. Conclusions. The proposed method significantly increases the high-frequency stability of RF amplifiers beyond the operating fre- quency range and simplifies the technological requirements for the design. The employment of RF amplifiers is more available almost without compromising their performance in the operating frequency range. The method is simple and easy to apply.

МОДЕЛЮВАННЯ РОЗПОДІЛЕНОГО НЕЛІНІЙНО-ОПТИЧНОГО ПІДСИЛЕННЯ У ТЕЛЕКОМУНІКАЦІЙНИХ ВОЛОКНАХ TRUEWAVERS ТА G.652

Common techniques for modeling of the nonlinear optical amplifiers, specifically based on the effect Raman effect, despite the simplicity of its technical implementation, are quite complex and cumbersome due to the necessity of theoretically describing the nonlinear interaction of many pump and signal optical waves using the corresponding systems of high-order differential equation. The fundamental limitations of such methodologies lie not only in the number of equations but also in the existence of special points in each equation describing the dynamics of signal waves (these points correspond to threshold values of pump power). Under these conditions, the solutions instabilities of the differential equations and their ambiguity sometimes have a detrimental impact on modeling results. An alternative modeling approach using the specified pump approximation requires particular investigations of its practical applicability to the analysis of distributed optical amplification in telecommunications fibers. Therefore, there is a need to determine the criterion for the applicability of the specified pump approximation for the development of a simplified model of nonlinear optical signal amplification under the conditions of their propagation along standard silica fibers. Among the undeniable advantages of analytical solutions obtained based on the simplified model there is the elimination of the mentioned constraints of solving systems of many differential equations. This article is devoted to modeling the dynamics of distributed Raman amplification, as function the length of standard single-mode optical fiber (SMF) and pump power. In justifying the proposed modeling methodology, it is shown that the parameters of active fibers and fiber Raman amplifier (hereinafter referred to as FRA) schemes correspond to the criterion for the applicability of the specified pump approximation. The paper presents an analytical expression for the criterion of the applicability of the specified pump approximation in the form of an upper limit of the signal power, which cannot exceed the amplified signal. Comparative analysis results of the distributed FRA parameters depending on the length of active fibers, such as G.652 and TrueWaveRS, are presented.

Spectral Analysis and Gain Modeling and Numerical Simulation of Bismuth-doped Fiber Amplifier

Fiber optic amplifier is an important component of fiber optic communication and the use of the properties of rare earth ions to dope the fiber core is an important way to obtain greater amplification and reduce loss. Because of the unique light-emitting properties of Bismuth ions, the Bismuth doped fiber amplifier (PDFA) has a wide range of applications in the field of fiber amplifier. This paper focuses on the spectral analysis of Bismuth-doped ( ) fiber amplifiers under different parameters by referring to the absorption spectrum of . And the energy level structure of was selected for a wide range of amplification windows → pumping scheme corresponding to the pumping wavelength of 950 nm, and the rate propagation equation and power transmission equation were established based on the previous work. The numerical simulations were also carried out by MATLAB programming. The effects of doping concentration, fiber length, and pump power on gain, noise index, and output power were analyzed and summarized by MATLAB plotting. In the future, researchers can use neural network algorithms to obtain the combination of Bismuth-doped fiber amplifier parameters that will achieve maximum gain, thus enabling advances in information transmission rates and distances in real-world communications.

Improving source-in-the-middle continuous-variable quantum key distribution using a heralded hybrid linear amplifier

A hybrid linear amplifier is inserted at the output of the source-in-the-middle distribution protocol to overcome the shortcomings of the transmission distance. The modified protocol aims to maintain a high key rate for long-distance transmission under high noise. It has the potential to significantly broaden the application range of the continuous variable quantum key distribution protocol. The effects of amplifier parameters and noise on the modified protocol are analyzed in detail with regard to applying it to a practical system. To make the simulation more realistic, the effect of finite size on the new protocol is taken into account. It will serve as a guideline for the future use of hybrid linear amplifiers. Different parameters can be adjusted to achieve the best performance for key rates of different quantum channels.