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In marine scientific research, ocean monitoring is crucial where the batterypowered sensor devices are placed under the water to collect different information like temperature, pressure, and turbidity in underwater sensor networks (UWSNs). Thus, keeping these devices active for longer periods is challenging. In the last decades, the piezoelectric transducer (PZT) material has been used widely for constructing more environmentally friendly energy harvesting systems. The PZT harvester offers a promising solution by eliminating the need for batteries for running devices in the future with less maintenance. The PZT harvester allows the system to generate higher voltage to run low-power devices. This paper designed and developed a new renewable energy harvester system using PZT transducers for running different types of underwater sensor devices like temperature, turbidity, and obstacle sensors. The proposed PZT-based energy harvester employs a twostage amplification model for generating higher voltage and current to run multiple devices. The sensing information collected from these sensors is transmitted to the cloud which is later utilized for analysis and decisionmaking. Experiment results show the proposed PZT-based energy harvester can generate a voltage of 13 volts (V) and a current of 43.3 milliampere (mA) equivalent to 562 milliwatt (mW) which is very good to run multiple low-power underwater sensor devices. [ABSTRACT FROM AUTHOR]

In this paper, we present an analysis of an operational trans-conductance amplifier (OTA) with two positive feedback. The direct current (DC) transfer function is obtained by analyzing the OTA using the drain current in the weak inversion region. The analysis results were verified through comparison with SPICE simulations, and the characteristics of the DC transfer function analysis for the OTA design are well matched with the simulation results. The designed OTA dissipates a low power of 41.4 nW, and features the slew rate is improved by 436% compared to a conventional OTA without two positive feedback. Additionally, a DC gain and a unity-gain bandwidth is improved by 36 dB and 6.7 times, respectively. The OTAs are designed for the 0.18 µm complementary metal-oxide-semiconductor (CMOS) process. [ABSTRACT FROM AUTHOR]

Background: Older adults with hearing loss struggle to communicate with care providers and experience higher mortality rates when hospitalized (Genther et al., 2015), even after controlling for age and comorbidities. Personal hearing amplifiers (PHAs), (e.g., Pocketalkers™), can improve communication with older patients. Methods: We conducted a scoping review to identify research gaps and summarize findings on the clinical use of PHAs with patients with hearing loss. After refining search terms relating to hearing loss and PHAs, we searched MEDLINE, Embase, PsycINFO, Cochrane Library, CINAHL Complete, Web of Science Core Collection, ERIC (Proquest), PubMed, ClinicalTrials.gov, International Clinical Trials Registry Platform, and the International Standard Randomised Controlled Trial Number Registry. We identified articles published in English between 1980 and 2022 that reported empirical outcomes relating to PHA use in clinical settings. Two reviewers independently extracted data from articles. We then organized data into an evidence map, and a narrative review summarizing outcomes. Results: From 4234 initially identified titles and abstracts, 12 met our criteria as full texts. These included three surveys on clinicians' awareness and use of PHAs, one evaluation of the acoustic output of a PHA, and eight interventions wherein PHAs were provided to patients with hearing loss. These papers used 10 different terms for PHAs and largely did not cite one another. Results showed high levels of satisfaction with PHAs, and consistently improved speech understanding. Despite this, care providers used devices inconsistently, with challenges around provider awareness, and device maintenance and location tracking. Conclusions: PHAs have a consistent positive effect on patients' ability to understand their care providers despite hearing loss. Barriers and facilitators to their use in clinical settings should be further explored. [ABSTRACT FROM AUTHOR]

The development of unique optical materials that provide amplification and lasing in new wavelength ranges is a major scientific problem, the solution of which is becoming the basis for the emergence of new optical technologies, which are primarily targeting the expanding of operating wavelengths in silica glass. In fact, one of the notable advances in the field of fiber optics over the past two decades has been the production of a new type of laser-active fibers (namely bismuth-doped fibers), which has made it possible to cover previously inaccessible (for rare-earth-doped fibers) spectral ranges, in particular O-, E-, S-, and U-telecom bands. The advance in this direction has led to further growth of the technological capabilities in the telecom industry for amplification and generation of optical radiation in various wavelength bands, which will result in the near future to overcoming the problem known as "capacity crunch" by means of expanding the data transmission range. Recently, bismuth-doped fibers have been actively studying in order to improve their characteristics, which would allow for efficient implementation of optical devices based on bismuth-doped fibers (BDFs) with deployed telecommunications systems. This is one of the dynamically developing areas, where progress has already manifested in form of emergence of new achievements, in particular commercially available various types of BDFs, as well as a series of novel fiber-optic amplifiers for the O- and E-bands. In this review, a number of scientific studies that have already led to a noticeable progress in the field of optical properties of BDFs and the practical implementation of optical devices (lasers and amplifiers) based on them are presented and discussed, with much attention to the achievements of recent years. [ABSTRACT FROM AUTHOR]

The sample and hold circuit (SHC), as a key module of the analog-to-digital converters (ADCs), directly affects the sampling speed and accuracy of the entire data acquisition system. Using TSMC 0.18 μm current-mode SHC for high-speed ADC was designed using CMOS technology. The proposed circuit combines a single amplifier and negative feedback structure to eliminate clock-feed through noise and high signal-to-noise distortion ratio (SNDR) from low power supply voltage and very low current consumption. Meanwhile, a differential structure is provided to reduce distortion caused by channel charge injection. Discussed design issues such as clock feedthrough noise, channel modulation effects, and power consumption. The design verification of the proposed current-mode SHC was completed through circuit layout simulation using CMOS model parameters. The results show that, from a 1.0 V supply and with a power consumption of 54.4 μW, the proposed circuit provides 71.2 dB SNDR, 11.53 bit effective number of bits, and a figure of merit of 1.8 fJ/conversion-step when the sampling frequency is 10 KS/S. [ABSTRACT FROM AUTHOR]

A vehicle–bridge system with a tunable amplifier is proposed to enhance the resolution of frequency identification in the vehicle scanning method (VSM), with a particular interest in the wheel-center spectra to account for pitching responses. Both semi-analytical and finite element formulations are established. The viability of the proposed amplifier–vehicle–bridge system is demonstrated in consideration of bridge types and boundary conditions, damping effect, and pavement irregularity. The major findings include the following: (1) The tunable feature of the amplifier enhances the visibility of higher-order bridge frequencies in its spectrum. (2) The vehicle responses can be removed in the cancellation conditions of the amplifier while the resonance conditions of the amplifier are not affected by vehicle damping under harmonic excitation. (3) The shifted higher-order bridge frequencies are distinctly shown in the wheel-center spectra, indicating the potential use of pitching responses in VSM. (4) The pitching responses have shown that the front-wheel spectrum has a higher resolution than the rear one, as influenced by the driving direction. [ABSTRACT FROM AUTHOR]

The present article presents critical aspects of RF system development process and its sequential phases along with associated challenges. It also discusses importance of active and passive components thermal behavior and their impact in overall system performance. The study on performance deviation of these components with temperature change has been reported. Potential issues for gain variation and frequency selectivity have been analysed and suitable solutions are explored accordingly. Implementation of temperature stabilization method in designed RF product has been carried out during prototype development. Practical achieved results are noted down during testing and measurement to monitor effectiveness of thermal stabilization mentioned in it. Finally, wideband flat gain response has been achieved by implementation of thermal stabilization for active and passive components to avoid any performance degradation. [ABSTRACT FROM AUTHOR]

Amplification of wideband high-frequency and microwave signals is a fundamental element within every high-frequency circuit and device. Ultra-wideband (UWB) sensor applications use circuits designed for their specific application. The article presents the analysis, design, and implementation of ultra-wideband differential amplifiers for M-sequence-based UWB applications. The designed differential amplifiers are based on the Cherry–Hooper structure and are implemented in a low-cost 0.35 µm SiGe BiCMOS semiconductor process. The article presents an analysis and realization of several designs focused on different modifications of the Cherry–Hooper amplifier structure. The proposed amplifier modifications are focused on achieving the best result in one main parameter's performance. Amplifier designs modified by capacitive peaking to achieve the largest bandwidth, amplifiers with the lowest possible noise figure, and designs focused on achieving the highest common mode rejection ratio (CMRR) are described. The layout of the differential amplifiers was created and the chip was manufactured and wire-bonded to the QFN package. For evaluation purposes, a high-frequency PCB board was designed. Schematic simulations, post-layout simulations, and measurements of the individual parameters of the designed amplifiers were performed. The designed and fabricated ultra-wideband differential amplifiers have the following parameters: a supply current of 100–160 mA at −3.3 V or 3.3 V, bandwidth from 6 to 12 GHz, gain (at 1 GHz) from 12 to 16 dB, noise figure from 7 to 13 dB, and a common mode rejection ratio of up to 70 dB. [ABSTRACT FROM AUTHOR]

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.

This study explores the pulse formation process in nuclear spectroscopy amplifier systems, with a focus on amplifier linearity analysis and bandwidth measurement. Nuclear spectroscopy is a crucial technique in nuclear physics studies, and the nuclear radiation detectors used must meet specific requirements, including the ability to differentiate the detected radiation energy levels. Pulse formation is a critical stage in this system, as these pulses carry important information about the interaction between radiation and its environment. Linearity testing of the amplifier and bandwidth measurement were conducted experimentally by adjusting input amplitude and frequency settings, as well as observing the amplifier's response to input signal variations. Measurement results indicate that adjustable pulse height and the amplifier system can produce Gaussian-shaped output pulses with appropriate rise times. However, potential issues arise due to limited pulse width and height, which can cause distortion and overload, thus disrupting the analysis of the generated pulses. [ABSTRACT FROM AUTHOR]

In the vehicle scanning method, using the amplifier as the tuned mass damper in the vehicle–bridge system has been shown to be able to scan the higher bridge frequencies clearly in the amplifier spectrum recently. To design a test vehicle enhanced by one or two amplifiers in practice, the analytical approach undoubtedly serves as the guideline. For this purpose, this study is aimed at deriving the analytical formulation for one amplifier-enhanced vehicle–bridge system and the semi-analytical formulation for two amplifier-enhanced vehicle–bridge system, while a miniature three-mass vehicle model is adopted. The correctness of the analytical formulations is verified by the finite element formulations through the dynamic responses of the amplifier, vehicle body, and bridge; good agreement is observed for all responses. The amplifier spectra are further provided to show the distinctly scanned bridge frequencies. [ABSTRACT FROM AUTHOR]

Chicken poultry business is becoming a crucial sector for sustainable food supply in the Philippines. To increase the health of chicken in coops and thus the output of chicken meat and eggs, several innovations and inventions have been made. The creation of an automated chicken feeding device might therefore be highly beneficial for the expansion of the poultry sector. This equipment may take the role of a worker in the chicken feeding process, introducing a semiautomatic procedure and thus solving the industry's labor shortage problem. The main processor of the automated chicken feeding system is a Raspberry Pi 3 Model B+. The machine consists of five main components: a Raspberry Pi with an amplifier that makes noise to draw the attention of free-range chicken; a Raspberry Pi with a pi camera that counts and detects the chickens; a Raspberry Pi with a servomotor that moves the food from storage to a container; a Raspberry Pi with a load cell that controls the number of feed to avoid food waste; and a Raspberry Pi with a temperature sensor that monitors the freshness of food. This enhances the coop's atmosphere while lowering labor costs, conserving food, and ensuring that the chicken are fed on time. [ABSTRACT FROM AUTHOR]

In this study, we have developed an amplifier waveguide module suitable for broadband communication in the sub-THz band. To achieve a waveguide module with excellent gain flatness characteristics, the effects of errors during the packaging procedures of the waveguide module and the space occupied by the bondwire were analyzed through an electromagnetic simulation. Furthermore, a photonics-based sub-THz wireless link with a carrier frequency of 288 GHz was established using a packaged amplifier module. The amplifier module was placed at the output of the sub-THz transmitter based on a uni-traveling-carrier photodiode and at the input of the sub-THz receiver. The maximum gain and 3 dB bandwidth of the amplifier module are 17.3 dB and 39 GHz, respectively. With this setup, we successfully transmitted a 100-Gbps 16-QAM modulated signal, employing a carrier frequency of 288 GHz, across a wireless distance of 100 m.

The development of unique optical materials that provide amplification and lasing in new wavelength ranges is a major scientific problem, the solution of which is becoming the basis for the emergence of new optical technologies, which are primarily targeting the expanding of operating wavelengths in silica glass. In fact, one of the notable advances in the field of fiber optics over the past two decades has been the production of a new type of laser-active fibers (namely bismuth-doped fibers), which has made it possible to cover previously inaccessible (for rare-earth-doped fibers) spectral ranges, in particular O-, E-, S-, and U-telecom bands. The advance in this direction has led to further growth of the technological capabilities in the telecom industry for amplification and generation of optical radiation in various wavelength bands, which will result in the near future to overcoming the problem known as “capacity crunch” by means of expanding the data transmission range. Recently, bismuth-doped fibers have been actively studying in order to improve their characteristics, which would allow for efficient implementation of optical devices based on bismuth-doped fibers (BDFs) with deployed telecommunications systems. This is one of the dynamically developing areas, where progress has already manifested in form of emergence of new achievements, in particular commercially available various types of BDFs, as well as a series of novel fiber-optic amplifiers for the O- and E-bands. In this review, a number of scientific studies that have already led to a noticeable progress in the field of optical properties of BDFs and the practical implementation of optical devices (lasers and amplifiers) based on them are presented and discussed, with much attention to the achievements of recent years.

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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.

Underwater sensor networks (UWSNs) are an emerging field in the research area as they have potential applications starting from pollution monitoring to defense and ocean exploration. Ocean monitoring is of great importance in marine scientific research. However, battery-operated devices utilized in such systems have limited power and maintenance is difficult. So, devices used underwater suffer from many research challenges and energy issues. Apart from all the problems, harvesting energy underwater is the main limiting factor. Nonrenewable energies come from sources that may not be replenished in our lifetime. Hence, it is very much essential to use renewable energy sources. Ocean has an unlimited amount of energy like wind energy, solar power, and tidal energy. Obtaining sufficient energy is sort of difficult since devices are underwater. Researchers are continuously working on it. Water energy is quite environmentally friendly, and it is a sustainable solution for a secure energy system. This paper implements a renewable energy system using piezoelectric (PZT) sensor, which generates sufficient power for lowpower underwater devices by employing two stage amplifier circuits. Experimental outcome shows the proposed energy harvesting system can generate a maximum voltage of 10.6 V and current of 10.1 mA which is sufficient to run low power underwater device. [ABSTRACT FROM AUTHOR]

A branched DNA-based electrochemical biosensor was designed to sensitively detect specific nucleic acids. On this platform, novel a branched DNA with three sticky ends could be used as a biosensor to sensitively and specifically detect nucleic acids. Meanwhile, we also employed branched DNA-modified AuNPs as a signal amplifier to further improve the sensitivity. Branched DNA sensors, target DNA, and DNA-modified AuNPs formed a sandwich structure to produce an electronic signal for target DNA detection. The reaction primarily involved DNA hybridization without bulky thermal cyclers and enzymes. We proved that the hybridization reaction easily occurred under different conditions, such as the NaCl concentration, reaction time, pH, and temperature, except for a pH lower than 4. The limit of detection could go as low as 0.09 pM (S/N = 3) with excellent specificity and selectivity. There was a correlation curve relationship between the peak current and the logarithm of the target DNA concentration (0.10 pM to 10 nM). The correlation coefficient reached 0.987. The electrochemical platform enables a branched DNA nanostructure to determine nucleic acids for disease diagnosis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A low-power common-mode detector (LPCMD) with process, supply voltage and temperature (PVT)-compensation technique for the dynamic amplifier in delta-sigma modulator (DSM) is proposed. By adopting the varying supply voltages to compensate the variation of the transistors' threshold voltage, the proposed LPCMD improves the robustness of the dynamic amplifier (DA). Additionally, the auxiliary circuit providing the varying supply voltages is realized by the low-power regulator, which has the advantage of low power and low complexity. To demonstrate the feasibility of the proposed LPCMD with the PVT-compensation technique, a second-order 2-bit quantization-based DSM is designed in 180 nm CMOS technology and the postlayout simulation is performed. The DSM achieves a signal-to-noise-and-distortion ratio (SNDR) and spurious-free-dynamic range (SFDR) of 93 dB and 95 dB at the sampling frequency of 204.8 kHz, respectively, with the power consumption of 11 µW, leading to a 171.6 dB SNDR-based Schreier figure-of-merit (FoMSNDR). Furthermore, the SNDR degradation of the DSM under all process corner and temperature from − 40 to 125 ℃ is less than 3 dB. The postlayout simulation result of the DSM verifies the feasibility and effectiveness of the proposed LPCMD and PVT-compensation technique. [ABSTRACT FROM AUTHOR]

This paper proposes a FINFET (Fin Field Effect Transistor)-based Voltage Difference Transconductance Amplifier (VDTA). This paper aims to provide an amplifier that will enable VDTA to achieve its desired characteristics. The circuit proposed for FINFET-based VDTA operates with a bias current order of 150μA and a source voltage of 0.9V. The active element makes the amplitude electronically tuneable with bias current. The designed circuit was implemented in both GPDK 180nm technology and FINFET technology using the Cadence Virtuoso tool. Various factors, including technology node components and the operating voltage provided by FINFET VDTA structures, are compared. A Monte Carlo simulation is conducted for the suggested circuit, which dissipates 187.53μW of power. In comparison to the standard VDTA, it exhibits notably low power dissipation. [ABSTRACT FROM AUTHOR]

Penelitian ini bertujuan untuk memudahkan dalam penimbangan sebuah objek dengan tampilan data digital menggunakan outseal PLC sebagai pusat kontrol. Penimbangan yang dilakukan dengan konvensional memerlukan pembacaan hasil yang berulang sehingga membutuhkan waktu lama dan hasil yang bervariasi disebabkan oleh faktor luar seperti pembacaan yang tidak tepat akibat sudut pandang yang berbeda. Dengan adanya timbang digital akan memudahkan pembacaan nilai dari hasil yang ditimbang. Metode yang digunakan dalam penelitian yaitu metode eksperimen dimana pada penelitian terdiri dari perancangan hardware, elektrikal, dan software. Dalam penelitian, outseal PLC yang berfungsi sebagai pusat kontrol. Input yang digunakan yaitu sensor load cell untuk mendeteksi berat. HMI weintek MT8071iP untuk membaca hasil penimbangan secara digital. Serial komunikasi antara HMI dengan outseal PLC menggunakan serial RS485. Pada penelitian ini dilakukan dua macam pengujian, pertama pengujian penimbangan berat yang berbeda dengan mengukur tegangan output load cell dari setiap massa yang ditimbang. kedua, Pengujian penimbangan dengan berat yang sama sebanyak sepuluh kali percobaan. Objek yang digunakan dalam pengujian timbangan digital ini yaitu granule cat litter yang diletakan dalam sebuah wadah. Dari pengujian pertama didapatkan hasil grafik perbandingan antara tegangan keluaran load cell dengan nilai berat yang ditimbang. Pada pengujian, didapatkan hasil pengukuran yang memiliki akurasi yang tinggi dan kesalahan yang rendah. Pada pengujian dari hasil penimbangan dengan berat yang sama sebanyak sepuluh kali percobaan didapatkan error rata rata 0.04% dan tingkat akurasi 99.96%.

The effect of load-pull on 3rd order intermodulation (IM3) radiation characteristics of a transmitting active phased array is studied and a general model for predicting the spatial distribution of fundamental tones and intermodulation products is introduced. The used data is obtained from a load pull measured amplifier prototype and a simulated linear antenna array, which are used in co-simulation of the system behavior. The system is optimized for maximum main tone beam powers with a two-tone excitation while satisfying a signal-to-IM3 ratio (SI3R) of 40 dB. In this paper, we demonstrate the case, where two separate beams are scanned independently from each other. The used load-pull system model achieves on average an improvement of 10.4 dB for SI3R, when compared to traditional small-signal modelling, while decreasing the main beam power densities by only 0.3 dB when compared to traditional small-signal modelling. Optimizing for SI3R degrades beam pattern by increasing beamwidths and decreasing sidelobe levels (SLL).

Amplification of wideband high-frequency and microwave signals is a fundamental element within every high-frequency circuit and device. Ultra-wideband (UWB) sensor applications use circuits designed for their specific application. The article presents the analysis, design, and implementation of ultra-wideband differential amplifiers for M-sequence-based UWB applications. The designed differential amplifiers are based on the Cherry–Hooper structure and are implemented in a low-cost 0.35 µm SiGe BiCMOS semiconductor process. The article presents an analysis and realization of several designs focused on different modifications of the Cherry–Hooper amplifier structure. The proposed amplifier modifications are focused on achieving the best result in one main parameter’s performance. Amplifier designs modified by capacitive peaking to achieve the largest bandwidth, amplifiers with the lowest possible noise figure, and designs focused on achieving the highest common mode rejection ratio (CMRR) are described. The layout of the differential amplifiers was created and the chip was manufactured and wire-bonded to the QFN package. For evaluation purposes, a high-frequency PCB board was designed. Schematic simulations, post-layout simulations, and measurements of the individual parameters of the designed amplifiers were performed. The designed and fabricated ultra-wideband differential amplifiers have the following parameters: a supply current of 100–160 mA at −3.3 V or 3.3 V, bandwidth from 6 to 12 GHz, gain (at 1 GHz) from 12 to 16 dB, noise figure from 7 to 13 dB, and a common mode rejection ratio of up to 70 dB.

Mathematical models of nonlinear parametric processes in THz devices based on a graphene metamaterial (multilayer graphene–dielectric structure) have been constructed. The models are based on the solution of nonlinear boundary value problems of diffraction for the system of Maxwell's equations with electrodynamic boundary conditions, where the graphene conductivity has a nonlinear dependence on the electric field strength approximated by a polynomial. A projection model in the integral form is constructed for the systems of nonlinear Maxwell's equations at combination frequencies. Mathematical simulation of the regimes of regenerative parametric amplification and parametric generation due to wave instability has been carried out. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction/Aims: Low‐amplitude compound muscle action potential (CMAP) suggests a neuromuscular pathology. Low amplitude will also result from a defective E1 electrode or its lead, that is, a technical artifact. The aim of this study was to investigate the effect of a defective E2 electrode lead on the CMAP. Methods: The CMAP was recorded using standard nerve conduction methodology and all electrode leads connected properly. Signals were then recorded when either the E1 or the E2 electrode lead was disconnected from the amplifier. This simulated a defective electrode lead. Studies were performed in four nerves of a healthy subject. Results: CMAP amplitude was reduced as expected when E1 was disconnected. Surprisingly, the amplitude fell by more than 65% when the E2 lead was disconnected, although E1 was properly connected. Discussion: E1 and E2 electrodes contribute to the CMAP. A defective recording electrode lead to E1 or E2 results in a low‐amplitude CMAP. The amplitude drop observed with a disconnected E2 lead was far greater than the signal recorded by the E2 electrode. This occurs due to the amplifier's inherent property to reduce the voltage difference between the E1 and E2 inputs. When E2 lead is defective, the CMAP will be an attenuated version of the signal recorded by the E1 electrode, and vice versa. When low‐amplitude CMAP amplitude is observed in all conduction studies, technical artifact should be considered before exploring the pathological basis for the abnormal results. [ABSTRACT FROM AUTHOR]

Features of high-energy and high-contrast imaging in a bistatic laser active optical system (laser monitor) are considered. A system is designed, where a brightness amplifier has a larger volume than a lighting source, which provides for high-contrast imaging of microobjects. The influence of the time shift between a superradiance pulse of the amplifier and the time of signal arrival at its input on the contrast and energy of images formed by one pulse is ascertained for the first time. It is shown that artifacts resulted from the superluminous radiation "parasitic" reflection and scattering from optical circuit elements significantly reduce the contrast and power of signals generated. This effect can be suppressed by means of generation of an amplifier input signal before the generation of amplified spontaneous emission; the optimal delay is 1 ns. [ABSTRACT FROM AUTHOR]

Although tremendous efforts have been devoted to investigating planar single-conductor circuits, it remains challenging to provide tight confinement of electromagnetic field and compatibility with active semi-conductor components such as amplifier, harmonic generator and mixers. Single-conductor spoof surface plasmon polariton (SSPP) structure, which is one of the most promising planar single-conductor transmission media due to the outstanding field confinement, still suffers from the difficulty in integrating with the active semi-conductor components. In this paper, a new kind of odd-mode-metachannel (OMM) that can support odd-mode SSPPs is proposed to perform as the fundamental transmission channel of the single-conductor systems. By introducing zigzag decoration, the OMM can strengthen the field confinement and broaden the bandwidth of odd-mode SSPPs simultaneously. More importantly, the active semi-conductor amplifier chip integration is achieved by utilizing the intrinsic potential difference on OMM, which breaks the major obstacle in implementing the single-conductor systems. As an instance, an amplifier is successfully integrated on the single-conductor OMM, which can realize both loss compensation and signal amplification. Meanwhile, the merits of OMM including crosstalk suppression, low radar cross section (RCS), and flexibility are comprehensively demonstrated. Hence, the proposed OMM and its capability to integrate with the active semi-conductor components may provide a new avenue to future single-conductor conformal systems and smart skins.

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. [ABSTRACT FROM AUTHOR]

Bismuth-doped fiber amplifiers offer an attractive solution for meeting continuously growing enormous demand on the bandwidth of modern communication systems. However, practical deployment of such amplifiers require massive development and optimization efforts with the numerical modeling being the core design tool. The numerical optimization of bismuth-doped fiber amplifiers is challenging due to a large number of unknown parameters in the conventional rate equations models. We propose here a new approach to develop a bismuth-doped fiber amplifier model based on a neural network purely trained with experimental data sets in E- and S-bands. This method allows a robust prediction of the amplifier operation that incorporates variations of fiber properties due to manufacturing process and any fluctuations of the amplifier characteristics. Using the proposed approach the spectral dependencies of gain and noise figure for given bi-directional pump currents and input signal powers have been obtained. The low mean (less than 0.19 dB) and standard deviation (less than 0.09 dB) of the maximum error are achieved for gain and noise figure predictions in the 1410–1490 nm spectral band. [ABSTRACT FROM AUTHOR]

In this paper, a new set of lorenz-like hyper-chaotic equation set is obtained using the anti-control procedure. The chaoticity of the system is verified by MATLAB simulations using mathematical analysis methods. A new OTA-C circuit is designed for the new equation set. In the difference term addition technique, synchronizing the OTA-C circuit with a memristor rather than a resistor is proposed. Circuit design and synchronization are performed in PSpice simulation. The fact that the transconductance of the OTA element can be easily adjusted with a bias current provides the parameters that will make the proposed dynamic circuit a chaotic oscillator. The advantage of the proposed synchronization method is that the memristor automatically reaches the value that will provide the required weight of the differential term required for synchronization, rather than the computational methods used to determine the weight. [ABSTRACT FROM AUTHOR]

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 κ i and the noise parameter μ i for modes i = 1 , 2 ) whenever κ 1 μ 2 2 + κ 2 μ 1 2 < 1 4 (κ 1 + κ 2) (1 + κ 1 κ 2) , 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). [ABSTRACT FROM AUTHOR]