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This article describes a master oscillator and power amplifier (MOPA) system with a single longitudinal mode (SLM) and high-repetition-frequency Pr3+:YLF active medium that was end-pumped by two 444 nm laser diodes. The Pr3+:YLF MOPA laser system produced a maximum pulse energy of 13.5 μJ with a pulse width of 130.2 ns at a pulse repetition frequency of 20 kHz, translating to a peak power of around 103.7 W. The Pr3+:YLF MOPA laser system’s output wavelength was 639.7 nm, and the line-width of its laser spectra was roughly 168 MHz. Additionally, at the highest output level, the laser beam quality did not decrease much due to amplification.

Successful operation of 4H-silicon carbide (SiC) MOSFET and integrated electronic circuit based on 4H-SiC MOSFET is reported at temperature up to $500~^{\circ }\text{C}$ in air. The high-temperature operation of the integrated circuit (IC) based on 4H-SiC MOSFET strongly depends on the reliability of metal/SiC contact. Based on the transfer length method (TLM), the Ni/Nb/n-type 4H-SiC junction exhibits ohmic behavior with specific contact resistance of $1.86\times 10^{-{4}}\,\, \Omega \cdot $ cm2 when operating at $500~^{\circ }\text{C}$. In contrast, the voltage gain of the amplifier is strongly governed by the variation of carrier mobility of the 4H-SiC MOSFET when temperature varies from room temperature to $500~^{\circ }\text{C}$. The experimental results show that, when the temperature is increased from $20~^{\circ }\text{C}$ to $300~^{\circ }\text{C}$ , the amplifier gain of the IC increased from 23.8 to 153.0. Though the voltage gain decreases when the temperature increases above $300~^{\circ }\text{C}$ , it is still higher than 50 at $500~^{\circ }\text{C}$. These results indicate that integrated electronic circuits based on this 4H-SiC MOSFET technology could be potentially used for harsh environment applications. [ABSTRACT FROM AUTHOR]

Six-port technology has been widely used in microwave systems, such as interferometric passive imaging. In this paper, an integrated Ka-band (32–36 GHz) six-port chip based on the 0.15-μm GaAs technology is designed and fabricated to simplify the circuit structure and miniaturize the volume of the imaging system. The designed chip integrates two amplifiers, two phase shifters, and a six-port circuit as part of an analog complex correlator. In this integrated chip, the crosstalk between the two amplifiers cannot be ignored. This paper analyzes the influence of the isolation between two amplifiers on the correlation results to guide the six-port chip design. In addition, considering that the radiometer system receives a broadband noise signal, the phase shifter needs to ensure that the phase shift range of each frequency point is the same under the same control conditions. Therefore, the phase shifter is designed with a high-pass and low-pass structure. The measurement results show that the isolation between the two amplifiers is greater than 20 dB, and the measured phase shift range and phase shift range error of the designed chip are 220° and 10°, respectively, with the control voltage varying from 0 to 1.5 V, which meets the requirements of the system. [ABSTRACT FROM AUTHOR]

This article presents two different classroom situations in which two pairs of students, one in grade 2 and the other in grade 6, attempted mathematically challenging problems through GeoGebra applets. Their reasoning, conjecture making, and argumentation is analyzed using Pea's (1985, 1987) theory of technology as amplifier and reorganizer and the notion of internal and external representations. GeoGebra played the role of amplifier and reorganizer in enabling students' explorations and led them to make conjectures. Furthermore, it was observed that students' static internal representations were enhanced to more dynamic external representations and this played a significant role in developing students' thinking. The three aspects of fidelity have been discussed with regard to the use of GeoGebra based applets and how such applets need to be critically designed and assessed in order to support students' learning. [ABSTRACT FROM AUTHOR]

"Nonstandard" equations (like a nonlinear Schrödinger one) that require very small steps in space and time in numerical computations are considered. Methods for time step increase via hyperbolization, i.e., adding the second time derivative multiplied by a small parameter, are studied. It is shown that the results can be improved by introducing an additional damping term associated with the same small parameter. The limiting values for the relation between the small parameter and the stepsizes in space and time are found. [ABSTRACT FROM AUTHOR]

Capacitance and inductance are fundamental electrical properties that play crucial roles in the operation and performance of antennas. In this comprehensive review, we delve into the principles, effects, and applications of capacitance and inductance in antennas. We explore how these properties influence antenna design, resonance, bandwidth, and radiation characteristics. Additionally, we discuss advanced concepts such as impedance matching, loading techniques, and tuning methods that leverage capacitance and inductance to optimize antenna performance. By gaining a deeper understanding of capacitance and inductance in antennas, engineers and researchers can unlock new possibilities for enhancing wireless communication systems and other electromagnetic applications. [ABSTRACT FROM AUTHOR]

This article presents a 135–155-GHz low-power and high-efficiency frequency multiply-by-9 (x9) frequency-modulated continuous-wave (FMCW) radar transmitter (TX). Starting from a 16-GHz frequency-chirping input signal, cascaded frequency triplers at $V$ -band (40–75 GHz) and $D$ -band (110–170 GHz) bring the signal to the $D$ -band, subsequently amplified and radiated via a power amplifier (PA) and an on-chip antenna at $D$ -band. The $D$ -band PA with a reduced gain of transistors at $f_{\max }$ /2 proposes a broadband gain-boosting technique, achieving a maximum achievable gain ($G_{\max }$) for broad frequency range with high-order embedding passives. The x9 chain proposes phase-controlled frequency triplers that align the phase of each harmonic contribution and boost the third harmonic output power, conversion gain, and dc-to-RF efficiency. Implemented in a 28-nm CMOS process, the TX achieves a measured effective isotropic radiated power (EIRP) of 9.4 dBm, a dc-EIRP efficiency of 16.6% while exhibiting an antenna gain de-embedded output power of 7.1 dBm, and a dc-to-RF efficiency of 9.7% with less than 77-mW dc power consumption. [ABSTRACT FROM AUTHOR]

In this paper, a new radial power combining method based on the vortex mode is proposed. The amplitude and phase distributions of the vortex mode in the circular waveguide and coaxial are analyzed. Besides, the excitation conditions of the vortex mode in the radial power combining/dividing network are analyzed by using the vector voltage transfer matrix. According to the theoretical analysis, a W-band 16-way radial power combiner/divider with equal amplitude and equal phase difference based on the circular waveguide vortex TE11 mode is designed and implemented. Compared to the conventional radial power combining methods, this design has great advantages in high-frequency expansion and interference mode suppression and can be applied to high-power systems. Moreover, by using 32 W-band GaN MMIC modules, a radial power combining amplifier is developed to achieve the active verification of the proposed power combiner/divider. The amplifier delivers an output power of about 67 W with the combining efficiency greater than 74% and power added efficiency close to 8% from 92 to 96 GHz. [ABSTRACT FROM AUTHOR]

All in all, clinical science characterizes anaemia disease as less tally of a red platelet. This illness is exceptionally successive in India and a few pieces of the entire world. This isn't straightforwardly influencing illness however the maker and initiator of numerous other blood-related issues. Biomedical has effectively built up a testing technique for the recognizable proof of such infection and sorted out the strategy for computing the quantity of check or scope of red platelets in human bodies. In view of a correlation of such information with ordinary human blood attributes specialists can distinguish the level of the pallor and its connected stage. This requires time like conventional blood revealing just as the precision of testing philosophy. With the help of this article, another method of recognizing similar information inside a brief timeframe is introduced. By processing the ordinary human platelet check with anaemia influenced blood through the bioelectronics circuit, it will be useful to sort out the presence of the illness. Rather than utilizing genuine blood, a substance blend comparable to human blood serum has been thought of and for sickness, synthetic creation has been modified. This may change results for genuine human blood however then circuit changes may assist us with improving the outcomes. The sugar meter and heart meter are as of now utilized in everyday life by normal individuals without the assistance of specialists. These commonsense outcomes may lead such instrument makers for building up the gadget for sickliness identification.

In order to reduce the loss of communication system based on orbital angular momentum (OAM), an Er3+-doped photonic crystal fiber (PCF) amplifier which can support amplification for 30 OAM modes is proposed. The structure of the PCF is optimized to obtain larger effective mode field area and effective refractive index difference. Then, the optimal PCF with a nonlinear coefficient lower than 0.002 m−1·W−1 is proposed, and it is used to setup an orbital angular momentum erbium-doped fiber amplifier (OAM-EDFA). Finally, an OAM-EDFA with a flat-high gain of about 28 dB, a DMG lower than 0.18 dB, and a NF no more than 4.4 dB is obtained. Compared with the existing OAM-EDFA, the gain of the proposed OAM-EDFA is increased by 6 dB. The OAM-EDFA based on the novel PCF designed in this work is of great interest to the OAM-based long-distance communication system.

Advances in the development of ultrahigh-frequency semiconductor electronics open wide opportunities for developing optimal schemes and designs of microwave power sources in the millimeter wavelength range providing high stability of the frequency and electromagnetic oscillation phase. Synchronized diode generators used in transmit/receive module for active phased array antennas, coherent low-power radar stations, etc. show great promise. The mode of external synchronization of semiconductor generators allows effectively implementing the task of creating output stages of the transmitters with high gain factor, low frequency noise and an output power level corresponding to the maximum power mode. This article presents the first of two parts of the study, which summarizes the results achieved so far in the development of synchronized oscillators based on impact ionization avalanche transit-time (IMPATT) diodes. The first part presents the electrodynamic designs of the oscillators, which are synchronized with an external source of microwave oscillations and contain a resonant oscillating system with a silicon IMPATT diode. The silicon two-drift IMPATT diode was chosen as an active element due to the fact that its use allows reaching significant levels of pulsed microwave power – an order of magnitude higher than those of the most well-known HEMT and pHEMT transistors in the millimeter wavelength range. It is shown that to reduce losses, the oscillating system should be made in the form of a radial resonator with a diode casing, which has distributed parameters. This eliminates the use of additional reactive inhomogeneities in the initial cross-section of the waveguide section of the generator. Due to the low quality factor of the resonant casing of the diode, the generalized quality factor of the microwave circuit takes the minimum value required to implement a stable generator synchronization process in the millimeter wavelength range. The second part of the work will be devoted to synchronized pulse generators with an output power of 20–150 W.

This paper presents a 160 GHz, D-band, low-noise amplifier (LNA) and a D-band power amplifier (PA) implemented in the Global Foundries 22 nm CMOS FDSOI. The two designs are used for the contactless monitoring of vital signs in the D-band. The LNA is based on multiple stages of a cascode amplifier topology with a common source topology adopted as the input and output stages. The input stage of the LNA is designed for simultaneous input and output matching, while the inter-stage-matching networks are designed for maximizing the voltage swing. The LNA achieved a maximum gain of 17 dB at 163 GHz. The input return loss was quite poor in the 157–166 GHz frequency band. The −3 dB gain bandwidth corresponded to 157–166 GHz. The measured noise figure was between 7.6 dB and 8 dB within the −3 dB gain bandwidth. The power amplifier achieved an output 1 dB compression point of 6.8 dBm at 159.75 GHz. The measured power consumptions of the LNA and the PA were 28.8 mW and 10.8 mW, respectively.

• Taking a commercial bismuth-doped fiber as an instance, we first measured the refractive index distribution of the BDF in the O-band using a self-developed fiber refractive index tester, and thereby obtained its actual mode-field area. Then, based on this we further propose an irregular Bragg bismuth-doped fiber with the refractive index growing layer by layer. • The results suggests that the effective mode-field area of this fiber reaches 401 um2 at 1320 nm, which is nearly 5.8 times that of a common single-mode BDF. Finally, we performed numerical simulations of the amplification performance based on this fiber. Under the condition of total pumping power of 8 W, the signal with −20 dBm input power obtains a gain of more than 54 dB and an NF of less than 5 dB at 1320 nm wavelength. • We believe this work demonstrates the great potential of this Bragg bismuth-doped fiber as an O-band high-gain amplifier and high-power laser. In recent years, O-band bismuth-doped fiber amplifier (BDFA) have been rapidly developed due to the fluorescence properties of bismuth-doped glass in the near-infrared (NIR) band, while there are still few studies on bismuth-doped fibers (BDF) with large mode fields as of now. In addition, although the use of a double-pass structure on the amplifier can lead to gain improvement, this also deteriorates the noise figure (NF). Therefore, the study of bismuth-doped fibers with large mode-field areas is a promising path to develop high-performance BDFA. In this work, taking a commercial bismuth-doped fiber as an instance, we first measured the refractive index distribution of the BDF in the O-band using a self-developed fiber refractive index tester, and thereby obtained its actual mode-field area. Then, based on this we further propose an irregular Bragg bismuth-doped fiber with the refractive index growing layer by layer. The results suggests that the effective mode-field area of this fiber reaches 401 um2 at 1320 nm, which is nearly 5.8 times that of a common single-mode BDF. Finally, we performed numerical simulations of the amplification performance based on this fiber. Under the condition of total pumping power of 8 W, the signal with −20 dBm input power obtains a gain of more than 54 dB and an NF of less than 5 dB at 1320 nm wavelength. This work demonstrates the great potential of this Bragg bismuth-doped fiber as an O-band high-gain amplifier and high-power laser. [ABSTRACT FROM AUTHOR]

[Display omitted] • A device responded to inert dsDNA without sequence restriction was proposed. • Any fragment of linear or circular dsDNA can be intercepted and transmitted. • The dsDNA-initiated circuits were supplemented. DNA molecules in life play a crucial role in various fields. However, DNA-based technologies confront significant difficulties in dealing with inert double-stranded DNA (dsDNA) with a blunt end without specific sequences. In this work, we utilized Thermus thermophilus Argonaute (TtAgo) and Vent DNA polymerase to construct an enzyme-driven device to convert and amplify arbitrary blunt-ended dsDNA into single-stranded DNA (ssDNA), thereby adapting to subsequent functional units. Based on the excellent performance of the dsDNA to ssDNA converter and amplifier (DSCA), inert dsDNA could be effectively identified. Additionally, DSCA accomplishes information interception and transmission, addressing the problem of dsDNA input response in DNA circuits and clinical diagnosis. Given these facts, this DSCA is expected to serve as a broad toolbox for the information transformation and amplification of inert dsDNA, prospering DNA circuit operations, and biosensing. [ABSTRACT FROM AUTHOR]

A high-attenuation wideband active common-mode filter (ACF) section is presented. Each section is composed of an active capacitor and a small common-mode (CM) inductor. The active capacitor is realized by using several coupling capacitors and a class-A bipolar-junction-transistor based amplifier for its low-cost, fast response, and good immunity to high voltage transients. The structure of the amplifier consists of a common-collector amplifier and a high-gain common-emitter amplifier with an active load. The working bandwidth of the ACF ranges from 150 kHz to 30 MHz. By cascading several ACF sections, a multistage structure that exhibits high filtering attenuation can be designed. The number of cascaded sections is optimized by considering the required filtering attenuation. The performance of single-stage and multistage ACFs is evaluated on two commercial power supplies with rated power of 90 and 1000 W, respectively. The CM noise of the power supplies with the proposed ACF and with the original passive filters is compared. The results show that the physical volume of the ACF is significantly smaller than that of the passive filter, and the power dissipation of the ACF is similar to that of the passive filter. [ABSTRACT FROM AUTHOR]

A wide variety of applications require high peak laser intensity in conjunction with a narrow spectral linewidth. Typically, injection-locked amplifiers have been employed for this purpose, where a continuous wave oscillator is amplified in a secondary external resonant amplifier cavity using a pulsed pump laser. In contrast, here we demonstrate a setup that combines a CW Ti:sapphire oscillator and pulsed amplifier in a single optical cavity, resulting in a compact system. Dichroic beam combination of blue wavelength semiconductor diodes and the green wavelength of a Nd:YAG laser allowed the simultaneous excitation of the Ti:sapphire crystal by both continuous wave and pulsed pump sources. A linewidth of <2 MHz is achieved in continuous wave operation, while the linewidth increases to about 10 MHz in the combined CW+pulsed mode with a pulse duration of 73 ns. A peak pulse intensity of 0.2 kW is achieved, which should enable efficient single-pass second harmonic generation in a nonlinear crystal. [ABSTRACT FROM AUTHOR]

IP3 is an important parameter of RF amplifiers. It is available from the datasheet and calculated from the interception between the line of the output power at fundamental frequencies and that of the power of the 3rd‐order intermodulation product conventionally measured from two‐tone tests. However, the measured output power at fundamental frequency will be affected by 3rd‐order intermodulation products. In this article, the impacts from 3rd‐order intermodulation products to the fundamental tones are analyzed. As an analytic formula‐based calibration solution, simple formulas that remove corresponding nonlinear effects are suggested. [ABSTRACT FROM AUTHOR]

Current and future wireless communication systems are designed to achieve the user’s demands such as high data rate and high speed with low latency and simultaneously to save bandwidth and spectrum. In 5G and 6G networks, a high speed of transmitting and switching is required for internet of things (IoT) applications with higher capacity. To achieve these requirements a semiconductor optical amplifier (SOA) is considered as a wavelength converter to transmit a signal with an orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM). It exploits the subcarrier’s power in conventional OFDM block in order to send additional bits beside the normally transmitted bits. In this paper, we optimized the SOA’s parameters to have efficient wavelength conversion process. These parameters are included the injection current (IC) of SOA, power of pump and probe signals. A 7 Gbps OFDM-SPM signal with a millimeter waves (MMW) carrier of 80 GHz is considered for signal switching. The simulation results investigated and analyzed the performance of the designed system in terms of error vector magnitude (EVM), bit error rate (BER) and optical signal-to-noise ratio (OSNR). The optimum value of IC is 0.6 A while probe power is 9.45 and 8.9 dBm for pump power. The simulation is executed by virtual photonic integrated (VPI) software. [ABSTRACT FROM AUTHOR]

In this research contribution, the electronically tunable first-order universal filter employing a single voltage differencing differential input buffered amplifier (VD-DIBA) (constructed from two commercially available integrated circuit (IC): the operational transconductance amplifier, IC number LT1228, and the differential voltage input buffer, IC number AD830), one capacitor and two resistors. The features of the designed first order universal filter are as follows. Three voltage-mode first-order functions, low-pass (LP), all-pass (AP) and high-pass (HP) responses are given. The natural frequency (w0) of the presented configuration can be electronically adjusted by setting the DC bias current. Moreover, the voltage gain of the LP and HP filters can be controllable. The phase responses of an AP configuration can be varied from 00 to −1800 and 1800 to 00 . The power supply voltages were set at ±5V. Verification of the theoretically described performances of the introduced electronically tunable universal filter was proved by the PSpice simulation and experiment. [ABSTRACT FROM AUTHOR]

Fin field-effect transistor (FinFET) based analog circuits are gaining importance over metal oxide semiconductor field effect transistor (MOSFET) based circuits with stability and high frequency operations. Comparator that forms the sub block of most of the analog circuits is designed using operational transconductance amplifier (OTA). The OTA is designed using new design procedures and the comparator circuit is designed integrating the sub circuits with OTA. The building blocks of the comparator design such as input level shifter, differential pair with cascode stage and class AB amplifier for output swing are designed and integrated. Folded cascode circuit is used in the feedback path to maintain the common mode input value to a constant, so that the differential pair amplifies the differential signal. The gain of the comparator is achieved to be greater than 100 dB, with phase margin of 65°, common mode rejection ratio (CMRR) of above 70 dB and output swing from rail to rail. The circuit provides unity gain bandwidth of 5 GHz and is suitable for high sampling rate data converter circuits. [ABSTRACT FROM AUTHOR]

IP3 is an important parameter of RF amplifiers. It is available from the datasheet and calculated from the interception between the line of the output power at fundamental frequencies and that of the power of the 3rd‐order intermodulation product conventionally measured from two‐tone tests. However, the measured output power at fundamental frequency will be affected by 3rd‐order intermodulation products. In this article, the impacts from 3rd‐order intermodulation products to the fundamental tones are analyzed. As an analytic formula‐based calibration solution, simple formulas that remove corresponding nonlinear effects are suggested. [ABSTRACT FROM AUTHOR]

The idea recommends a new class of optical amplifiers based on parametric a parametric instability in plasma known as stimulated Brillouin scattering (SBS). In SBS there is an exchange of energy between electromagnetic radiation and an ion acoustic wave (IAW) propagating through plasma. IAWs in plasmas are analogous to sound waves propagating through gases or solids. The proposed amplifier consists of two stages. In the first stage the input optical signal is amplified through stimulated emission in a gain medium. In the second stage this amplified signal undergoes further amplification parametrically through the process of SBS. [ABSTRACT FROM AUTHOR]

The design approaches of the overlapping-mode extended interaction klystrons (EIKs) are presented to satisfy the requirement for broadband terahertz power amplifiers. Since all the cavities are designed and tuned to operate in multiple-cavity modes, the overlapping-mode EIKs can provide high output power over a wider frequency band. The circuit characteristics of the overlapping-mode EIKs are studied, including the dispersion curve, the coupling coefficient, and the frequency interval between cavity modes. Moreover, a six-cavity EIK operating at 0.34 THz is designed to demonstrate the broadband output capability of the overlapping-mode EIKs. The $2\pi $ -mode and its adjacent axial mode, the $\pi $ /13-mode, are chosen as the operating modes of the designed EIK. The 3-D particle-in-cell (PIC) simulation predicts a 3-dB bandwidth of 2.9 GHz for the designed power amplifier at a small-signal level or in saturation. Driven by an input power of 10 mW, the amplifier can provide the output power of 3.9 W, and the corresponding gain is 25.9 dB. When the input power is 150 mW, the amplifier is partially saturated and can provide the output power of 33 W with a corresponding electronic efficiency of 1.23%. [ABSTRACT FROM AUTHOR]

A low voltage low power two-stage CMOS amplifier with high open-loop gain, high gain bandwidth product (GBW) and enhanced slew rate is presented in this work. The proposed circuit makes use of folded cascode gm-boosting cells in conjunction with a low voltage gain enhanced cascode mirror using quasi-floating gate (QFGMOS) transistors. QFGMOS transistors are also used in input pair and adaptive biasing, which facilitate large dynamic output current in the presented circuit. Consequently, the slew rate is enhanced without much increase in static power dissipation. The unity gain frequency (UGF) and dc gain of the circuit are 29.4 MHz and 132 dB, respectively. The amplifier is operated at 0.6 V dual supply with 89 μ W power consumption and has a nearly symmetrical average slew rate of 51.5 V/ μ s. All simulations including Monte Carlo and corner analysis are carried out using 180-nm CMOS technology for validating the design with help of spice tools. [ABSTRACT FROM AUTHOR]

In this article shows the results of an experimental study of the amplitude-frequency characteristics of the quasi-complementary emitter followers on three structural injection-voltaic transistors. [ABSTRACT FROM AUTHOR]

A pair of a scintillator and a Photomultiplier Tube (PMT) is often used as a Hard X-Ray (HXR) radiation detector in existing tokamaks such as JET, EAST, COMPASS or ASDEX-U. Future nuclear fusion reactors such as ITER or DEMO will use more powerful magnets and confine a larger volume of hot plasma. Placement of the detectors used for plasma diagnostic will be constrained by high temperatures, magnetic fields and ionizing radiation present near the tokamak vessel. It might be necessary to move detectors away from tokamak to a safer location. This might generate problems with pulse discrimination and transmission of the signal. In the case of the ITER tokamak, sensitive electronics such as digitizers cannot be installed close to the reactor due to harsh environmental conditions. A new approach to component placement is needed to protect those devices. The PMT signal will be transmitted via an over 100 m long coaxial cable to the digitizer located in the adjacent diagnostic building. The long cables will introduce additional signal attenuation. Also, the RF noise from the tokamak environment can couple into the signal. To improve the signal-to-noise ratio a dedicated PMT amplifier with a high output range (from + 1.5 to − 11 V) was proposed.The paper presents issues with signal transmission in HXR diagnostic systems and includes a discussion on the methodology of PMT signal transmission in the conditions of the future tokamaks. A proposal of guidelines for selection of the signal chain components and design of a dedicated PMT amplifier is part of this paper. [ABSTRACT FROM AUTHOR]

This article proposes a voltage-to-frequency converter (VFC) design using unipolar metal-oxide thin film transistor (TFT) technology. The proposed VFC has an integrator and Schmitt trigger based structure. This structure has the advantages of constant power consumption, full-swing output, and low circuit complexity compared to the early designs. To verify the proposed design, SmartSpice simulation based on a Rensselaer Polytechnic Institute (RPI) model whose parameters are turned to fix the measured characteristics of our indium tin oxide- (ITO-) stabilized ZnO TFTs is carried out. The ITO-stabilized ZnO TFT has a single-gate staggered structure. Its typical field-effect mobility, threshold voltage, on/off current ratio, and subthreshold-slope are 14.5 cm2/Vs, 0.5 V, $1.2{\mathrm {\times }} 10^{8}$ , and 77 mV/decade, respectively. Simulation results show that the proposed VFC has maximum linearity error less than 1.8%, tuning sensitivity about 1 kHz/V, and power consumption less than $130~{\mu }\text{W}$ even under device variations. These performances are competitive compared to the state-of-the-arts. When configured to an analog-to-digital converter (ADC), 6 bit resolution and 14 S/s sampling rate can be realized. These results indicate that the VFC can find potential applications in flexible large-area low-voltage sensor interfaces for quasi-static signals.

This paper proposes a simultaneous output power- and gain-matching technique in a sub-THz power amplifier (PA) design based on a maximum achievable gain ( $G_{max}$ ) core. The optimum combination of three-passive-elements-based embedding networks for implementing the $G_{max}$ -core is chosen considering the small- and large-signal performances at the same time. By adopting the proposed technique, the simultaneous output power- and gain-matching can be achieved, maximizing the small-signal power gain and large-signal output power simultaneously. A 150 GHz single-ended two-stage PA without power combining circuit is implemented in a 65-nm CMOS process based on the proposed technique. The amplifier achieves a peak power gain of 17.5 dB, peak power added efficiency (PAE) of 13.3 and 16.1 %, saturated output power ( $P_{sat}$ ) of 10.3 and 9.4 dBm, and DC power consumption of 86.3 and 52.4 mW, respectively, under the bias voltage of 1.2 and 1 V, which corresponds to the highest PAE, gain per stage and $P_{out}$ per single transistor among other reported CMOS D-band PAs.

This paper introduces a high-speed mixed-signal readout array in 130-nm CMOS for the amplification and digitization of picoampere-range signals. Its design is inspired by the needs of emerging DNA sequencing technologies based on biological nanopore sensors. To overcome switching and substrate noise this system adopts an in-pixel analog-to-digital converter (ADC) architecture and a novel readout technique while consuming 10x less power than similar designs described in the literature. The in-pixel ADC architecture is inherently scalable and immune to electrical interference which can be extended to 100s of channels. With a 5 pF input capacitance, the amplifiers achieve a maximum bandwidth of 100 kHz and demonstrate a noise floor as low as 4 fA/ $\sqrt {\text{Hz}}$ and a gain in the range of $\text{G}\Omega $ at 10 kHz. Circuit noise behaviour and theoretical maximum performance estimates using behavioural models are also discussed.

Global data traffic is continuously growing year by year. In this regard, telecom companies faced the problem of increasing data transmission rate, which is becoming more and more challenging. One of options that could help to increase optical links capacity is an expansion of the spectral range of DWDM systems used in telecom by inclusion of the O-band and/or the E-band. An ability to engage these spectral ranges directly related to the presence of suitable effective optical amplifiers. In this work, we studied different modifications of Bi-doped fiber amplifier operating in the O- and E-bands in order to obtain the widest gain spectrum in a single device. In particular, one- and two-wavelength pumping and gain-clamped schemes, as well as usage of a Bi:P $_\text {2}$ O $_\text {5}$ -SiO $_\text {2}$ and Bi:GeO $_\text {2}$ -SiO $_\text {2}$ fibers combination, were considered. As a result, an amplifier with 150 nm –6 dB bandwidth, $>$ 25 dB peak gain operating in the range from $\sim$ 1300 to $\sim$ 1450 nm was developed. To achieve the highest spectral width, we compare a gain-clamped at 1280 nm cavity pumped at 1180 nm with dual pump scheme at 1180 nm and 1270 nm along with a combination of active media composed of Bi:P $_\text {2}$ O $_\text {5}$ -SiO $_\text {2}$ and Bi:GeO $_\text {2}$ -SiO $_\text {2}$ fibers. [ABSTRACT FROM AUTHOR]

This study presents a modern concept of the amplifier that can be used in the vehicle–bridge interaction system to enhance the performance of vehicle scanning method by using the semi-analytical approach. Based on the sophisticated vehicle model, the vibration amplifier is introduced to the pinnacle of the vehicle model to compose an amplifier–vehicle–bridge (AVB) system. With this additional degree of freedom, the semi-analytical solutions have shown that the vehicular responses are amplified in comparison with those obtained by the vehicle–bridge interaction system without an amplifier. The proposed AVB system can be served as reference solutions when more parameters or complex situations are to be investigated in an AVB system using a simply supported bridge. [ABSTRACT FROM AUTHOR]

This article describes the basic principles and provides useful tips for recording event-related potentials (ERPs) in psychology experiments. The topics include: selection of electroencephalogram (EEG) amplifiers and choice of recording parameters, types and choice of electrodes, explanation of balanced non-cephalic electrode reference, a step-by-step procedure to determine electrode positions according to the International 10-20 system, techniques for secure placement of dish electrodes onto the scalp, explanation of what to observe in the EEG to monitor subject conditions during experiments, and many practical tips for reducing noise and artifacts in EEG data. The article is intended to be a desk-side guide for beginners and for those confronting difficulties in obtaining high-quality, artifact-free data in ERP experiments. [ABSTRACT FROM AUTHOR]

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The presented paper aims elaborate on and understand the motors and control of the propulsion systems. Motion control systems are the backbone of many applications in a wide range of industries. Their use ensures greater accuracy, reliability, and efficiency. Many of us already work with motion control systems. Others may encounter a motion control system in their workplace. Therefore, it is essential to understand each component of motion control. Motion control systems are generally divided into two types: opened circuits and closed circuits. Each system has its advantages and disadvantages. Open-circuit systems are usually more affordable, while closed-circuit systems can achieve greater accuracy and complexity. The motion controller is the brain of the system which controls the motion path, closing the servo circuit and executing the sequence. The controller sends a low-power command signal to the motor or amplifier in digital or analog form. Moving the motor amplifies the signal, produces torque and sets the load in motion, so that the motor drive controls the speed, torque, and direction, determining the power of the motor. Finally, the response sensors record the performance and send information to the controller of any change in engine position or speed. Choosing the right motion control components in relation to the system architecture is crucial as it determines the performance of the machine or the performance of the automated system. [ABSTRACT FROM AUTHOR]

The next generation of the wearable and implantable high-density neural signal sensing systems must be multi-channel and power efficient. The integrated instrumentation amplifier (IA) within such sensing system forms the critical element for signal detection and pre-processing. Inverter-based IA provides a low power consumption and a small die area. However, the conventional inverter yields a single-ended (SE) topology, which suffers from a poor common-mode rejection ratio (CMRR). In this paper, a pseudo-differential inverter is proposed. It provides an alternative solution to increase CMRR without the need for external control circuit. The pseudo input terminal is simply employed by equally splitting the input transistor of SE inverter into two and connected in parallel (reuses the active load), to provide a feedback path to dynamically reduce the common-mode interference. With respect to the SE topology, CMRR is much improved (approximately 75% higher) without any significant increasing of die area and power consumption. The proposed IA provides circa 117 dB CMRR, 1.5 $\text{G}\pmb \Omega $ input impedance at 100 Hz, and consumes $8.3~\pmb \mu \text{W}$. [ABSTRACT FROM AUTHOR]

High-performance single-transistor current source is crucial to analog design in advanced CMOS processes. Various approaches to enhance the output resistance of single-transistor current source are studied in this brief in the view of adaptive control. Then a novel compact implementation is proposed, and used to build a fully differential OTA with improved dc gain and common-mode rejection in a 55 nm CMOS with a supply of 1.1 V. [ABSTRACT FROM AUTHOR]

In this work, an experimental study was carried out about the construction of an amplification equipment based on the phenomenon of stochastic resonance (SR), which was initially thought to detect spikes and bursts from human and animal neuronal tissue, both in vitro (from microelectrode array, MEA) and in vivo, from electrodes in the cerebral cortex of mammals. The implemented equipment was called CADSR (Computer-Aided Digital Stochastic Resonator) and brings as innovation the fact of being controlled and monitored by the computer, through a graphical interface that allows an automatic tuning, making it possible to obtain the optimum level of noise to maintain SR in real-time. Experimental results show that for electrical signals from multi-electrode arrays with amplitude below 25 microvolts, the amplification system using stochastic resonance is better than conventional amplifier systems, which use operational amplifiers in linear configurations.

This article presents two methods, the block approach indefinite admittance matrix (BA-IAM) and the estimation-by-inspection, to analyse the effects of deterministic noise on single-stage, single-ended amplifiers by extending the indefinite admittance matrix. The proposed methods are used to develop a generalised two-port network analysis for the commonly used amplifier topologies, in the presence of the supply, ground, bulk, and input noise sources. Various illustrative case studies (common-source, common-gate, and push-pull amplifiers) are considered to validate the analytical method of different CMOS technology nodes (180 nm, 110 nm, and 28 nm) and foundries (Lfoundry, UMC, and TSMC). Both the proposed methods are compared with the relevant existing methods in terms of mean percentage error (MPE), and computational complexity. The mathematically derived expressions using two methods show less than 4% MPE when compared with the schematic simulation results, obtained by the SPICE based simulations. Also, the post-layout simulations (PLS) results for all the examples (designed in CMOS 180 nm Lfoundry technology) show excellent matching with schematic simulations. The proposed methods can be further applicable to antennas, complex circuits, digital circuits, etc.

Electromagnetic emissions from earthquakes are known as precursors and are of considerable importance for the purpose of early alarms. The propagation of low-frequency waves is favored, and the range between tens of mHz to tens of Hz has been heavily investigated in the last thirty years. This work describes the self-financed Opera 2015 project that initially consisted of six monitoring stations over Italy, equipped with electric and magnetic field sensors, among others. Insight of the designed antennas and low-noise electronic amplifiers provides both characterization of performance (similar to the best commercial products) and the elements to replicate the design for our own independent studies. Measured signals through data acquisition systems were then processed for spectral analysis and are available on the Opera 2015 website. Data provided by other world-known research institutes have also been considered for comparison. The work provides examples of processing methods and results representation, identifying many exogenous noise contributions of natural or human-made origin. The study of the results occurred for some years and led us to think that reliable precursors are confined to a short area around the earthquake due to the significant attenuation and the effect of overlapping noise sources. To this aim, a magnitude-distance indicator was developed to classify the detectability of the EQ events observed during 2015 and compared this with some other known earthquake events documented in the scientific literature.

Early heart disease detection could be vital and some other diagnostic ways are being developed. In this paper, a lowcost tool for a diagnostic that analyzes the digitized heartbeat sound is given. This can be used to detect heart anomalies. The instrument shows the heart sound and also keeps a patient's long-term record for future use. The signal from the heart provides a lot of knowledge about the heart and offers an initial diagnosis recommendation. The electronic stethoscope uses the condenser microphone, preamplifier circuit, and filter circuit. The optimum filter is Butterworth with a fourth-order Sallen key low pass filter topology with a gain of 0.707 volts, -3.01 dB, and a fourth-order high pass filter with a gain of 0.782 volts, -2.137 dB. The frequency of the heart sound is about 20 Hz – 120 Hz in general. Therefore, the lower cutoff frequency of the filter is set to 20 Hz, while the higher cutoff frequency set to 120 Hz. The evaluation used to measure the performance of an electronic stethoscope is to compare with a conventional stethoscope, the recorded sound is the same.

Entanglement distribution task encounters a problem of how the initial entangled state should be prepared in order to remain entangled the longest possible time when subjected to local noises. In the realm of continuous-variable states and local Gaussian channels it is tempting to assume that the optimal initial state with the most robust entanglement is Gaussian too; however, this is not the case. Here we prove that specific non-Gaussian two-mode states remain entangled under the effect of deterministic local attenuation or amplification (Gaussian channels with the attenuation factor/power gain κi and the noise parameter μi for modes i=1,2) whenever κ1μ22+κ2μ12<14(κ1+κ2)(1+κ1κ2), which is a strictly larger area of parameters as compared to where Gaussian entanglement is able to tolerate noise. These results shift the “Gaussian world” paradigm in quantum information science (within which solutions to optimization problems involving Gaussian channels are supposed to be attained at Gaussian states).

This article reports the concept of a double maximum achievable gain (double- $G_{\mathrm{ max}}$) core for the implementation of sub-terahertz high-gain amplifier design. The double- $G_{\mathrm{ max}}$ core is a $G_{\mathrm{ max}}$ core that adopts another linear, lossless, and reciprocal network that satisfies the $G_{\mathrm{ max}}$ condition onto an even number of cascaded transistor-level $G_{\mathrm{ max}}$ cores. It is shown that the double- $G_{\mathrm{ max}}$ core, due to its regenerative nature, can achieve much higher gain per stage than that of the same number of cascaded $G_{\mathrm{ max}}$ cores while satisfying the unconditional stability. Implemented in a 65-nm CMOS process, by adopting the proposed double- $G_{\mathrm{ max}}$ core, 247- and 272-GHz two-stage amplifiers achieve the peak gain of 18 and 15 dB, the gain per stage of 9 and 7.5 dB, and the PAE of 4.44% and 2.37%, respectively, while dissipating 21.5 mW. [ABSTRACT FROM AUTHOR]

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Satellite-cellular convergence promises to enable higher millimetre-wave bandwidth (data rate); beamformed better signal alignment (higher system efficiency); multi-connectivity (higher data rates); and new use cases (verticals). Harnessing these opportunities will depend on overcoming challenges spanning shorter distance/reduced coverage and component complexity; construction of antenna array and over-the-air testing; coexistence issues between multiple mobile communication connections; performance tests; cybersecurity. This paper presents a broadband Monolithic Microwave Integrated Circuit (MMIC) Low-Noise Amplifier (LNA) based on a 0.15 µm gate length Gallium Arsenide (GaAs) pseudomorphic high electron transistor (pHEMT) technology for satellite-cellular convergence use cases applications. The designed three-stage 23-28 GHz LNA demonstrates an industry-leading flat gain response of 30 dB, a noise figure of 1.70 dB and a very low power dissipation of 43 mW. The differential sensitivity response spans 0.01 µs to 0.04 dBm/Hz over the upper and lower ends of the channel bandwidths of the 5G New Release frequency range n258 band (24.25-27.58 GHz). Moreover, the millimetre-wave regenerative sensitivity analysis of the designed LNA holds a grand promise for real-time component-level reconfiguration applications. These applications include dynamic spectrum access; regenerative wireless transponder-transceiver technologies support; active spectrum resource usage; distributed sensing over a multi-standards wideband spectrum; and massive and complex timevarying spectrum datasets/features. [ABSTRACT FROM AUTHOR]