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A numerical model describing a magnonic active ring oscillator (MARO) based on a microscopic spin-wave delay line is proposed. The model considers excitation, propagation, and reception of the magnetostatic surface waves in a yttrium iron garnet (YIG) magnetic film with a thickness in the nanometer range. The waves are excited and received with a microscopic coplanar antenna. We employed the model to analyze the influence of the YIG-film thickness and the distance between the antennas on the MARO performance characteristics. We showed that an increase in the delay time inserted by the delay line reduces the phase noise of the MARO and increases the auto-oscillation threshold. In addition, we found a relation between the auto-oscillation threshold, the thickness of the YIG film, and the distance between the antennas. The relation helps design miniature MAROs and suggests a way to reduce the phase noise of the device. The model predicts a phase noise level of −115 dBc/Hz at a 10 kHz offset from an oscillation frequency in the vicinity of 5 GHz for the MARO based on a 100 nm-thick YIG film and 56 μm of distance between the coplanar nano-antennas of the YIG-film based delay line. We believe that this is a clear way forward to microminiaturize the time-delay feedback microwave auto-oscillators. A further reduction in the phase noise down to −125 dBc/Hz at a 10 kHz offset is found in a model of cascaded connection of several microscopic spin-wave delay lines. [ABSTRACT FROM AUTHOR]

We demonstrate an approach to two-dimensional electronic spectroscopy (2DES) that combines the benefits of shot-to-shot detection at high-repetition rates with the simplicity of a broadband white light continuum input and conventional optical elements to generate phase-locked pump pulse pairs. We demonstrate this through mutual synchronization between the laser repetition rate, the acousto-optical deflector, the pump delay stage, and the CCD line camera, which allows for rapid scanning of pump optical delay synchronously with the laser repetition rate, while the delay stage is moved at a constant velocity. The resulting shot-to-shot detection scheme is repetition rate scalable and only limited by the CCD line rate and the maximum stage velocity. Using this approach, we demonstrate the measurement of an averaged 2DES absorptive spectrum in as much as 1.2 s of continuous sample exposure per 2D spectrum. We achieve a signal-to-noise ratio of 6.8 for optical densities down to 0.05 with 11.6 s of averaging at 100 kHz laser repetition rate. Combining rapid scanning of mechanical delay lines with shot-to-shot detection as demonstrated here provides a viable alternative to acousto-optic pulse shaping approaches that is repetition-rate scalable, has comparable throughput and sensitivity, and minimizes sample exposure per 2D spectrum with promising micro-spectroscopy applications. [ABSTRACT FROM AUTHOR]

Microring resonators (MRRs), typically comprising straight and ring waveguides, have played pivotal importance in recent years as far as integrated on-chip systems are concerned. The evanescent coupling in such MRR or solid microdisk resonators is very sensitive to the coupling gap between two waveguides, which affects the resonator's performance. To overcome the stringent requirement of the gap between two waveguides, we propose a coupling-gap-free, on-chip ellipsoid microresonator. The theoretical framework has been deduced to attain the modal properties of such integrated microresonator geometry, which shows an excellent agreement with the finite difference time domain simulations and experimental results. The absence of a coupling region makes the device uniquely compact and robust, with an insertion loss of ∼ 5 dB. The resonator's geometrical dimensions can also be conveniently scaled within certain constraints. The proposed device can be a potential alternative to MRRs and could help in applications such as optical filters, delay lines, on-chip sensing, and many more. [ABSTRACT FROM AUTHOR]

In this study, delay line surface acoustic wave devices were prepared using a 128° Y-cut LiNbO3 piezoelectric substrate. Pure MoS2 and composite materials of MoS2 and SiO2 with various morphologies were sprayed to form sensitive layers. By adjusting the amount of NH4OH catalyst in the precursors, the particle sizes of SiO2 nanospheres were successfully controlled at 70, 200, and 300 nm by the sol-gel method. SiO2 nanospheres were then added to the precursor for preparing rosette-shaped MoS2, and nanocomposites were synthesized by the hydrothermal method. As a result, two types of composite material were obtained, namely, the S-M structure and the M-S structure. As ammonia gas sensors, the results showed that all the sensors exhibited negative frequency shifts as the NH3 gas concentration increased. Surface area and pore size distribution analyzer (BET) analysis showed that the highest specific surface area of 115.57 m²/g occurred on the S-M structural composite material. The sensor using the S-M structural composite material has a sensitivity of 1932 Hz/ppm to NH3 gas. The sensing linearity R-squared value is approximately 0.99, with continuous dynamic sensing at NH3 gas concentrations of 5-50 ppm. Finally, we revealed that decorating MoS2 with SiO2 nanospheres can improve the adsorption of ammonia molecules and significantly enhance sensitivity. [ABSTRACT FROM AUTHOR]

Background Aims Methods Results Conclusions Connecting an infusion line to a closed stopcock results in pressurization of fluid within the syringe infusion pump assembly leading to flow irregularities when opening the stopcock and activating the pump.It was the purpose of this study to assess the extent of pressurization under different conditions and its impact on start‐up fluid delivery.Intraluminal pressures and start‐up fluid delivery at 1 mL/h flow rate were assessed with connection of the infusion line 1 min (delayed connection) or immediately after purging (immediate connection) using two different infusion lines made from polyvinylchloride (PVC) or polyethylene (PE).Delayed connection resulted in an increase of intraluminal pressures from zero to 5.1 [4.5 to 5.7] mmHg with the PVC line and from zero to 47.1 [44.8 to 49.3] mmHg with the PE line (mean difference 42.0 [95% CI 39.3–44.7] mmHg; p < .0001). Immediate connection resulted in an increase of intraluminal pressures from zero to 44.3 [41.8–46.8] mmHg with the PVC line and from zero to 61.3 [57.2–65.4] mmHg with the PE line (mean difference 17.0 [95% CI 11.8–22.2] mmHg; p < .0001). The increase in intraluminal pressures was significantly higher with PE lines for both delayed and immediate connection when compared to the PVC lines (mean difference 29.5 [95% CI 19.3–39.7] mmHg; p < .0001). Related fluid volumes delivered at 10 s and 360 s after starting the pump ranged from −252% to 1321% (10 s) of expected infusion volumes and from 59% to 129% (360 s), respectively.Both, timing of infusion line connection after purging and infusion line characteristics considerably affect intraluminal pressures and start‐up fluid delivery when connecting a new syringe infusion pump assembly to a closed stopcock. Consecutive alterations in drug administration can have considerable hemodynamic consequences when dealing with catecholamine infusions in critically ill patients. [ABSTRACT FROM AUTHOR]

Optical encryption technology attracts considerable attention in the field of information encryption, information storage, and anti‐counterfeiting. However, optical encryption based on conventional on/off mode still faces issues such as low scalability, ease of cracking, and poor storage capacity; multi‐dimensional and high storage capacity information encryption systems are thus needed. Herein, a programmable information encryption circuit system is demonstrated by constructing a delay light‐emitting diode (LED) array using multi‐color phosphorescent carbon nanodots (CNDs) with versatile lifetimes. The CNDs show adjustable luminescence wavelength and lifetime from 192 to 1148 ms. The programmable delay luminescent circuit provides an intricate framework for meticulously integrating an LED array, enabling the creation of intricate patterns or alphanumeric codes. These intricate designs are engineered to serve as a component of an encryption system, which can be deciphered and unveiled under a specific delay time range. This study demonstrates the feasibility and superiority of the system as a new type of information anti‐counterfeiting encryption technology, providing a new concept for exploring the field of integrated circuit anti‐counterfeiting and encryption. [ABSTRACT FROM AUTHOR]

This paper presents the design, implementation, and validation of a femtosecond timing system aimed at achieving precise time control and phase synchronization for large particle accelerators. A prototype system utilizing a continuous wave laser was developed, focusing on minimizing timing jitter and long-term phase drift. Key components include an optical delay line for coarse adjustments and a fiber stretcher for fine-tuning, achieving an adjustment precision of 1 femtosecond. The system incorporates a phase detection module with a non-In-phase/Quadrature downconversion approach, enabling high-accuracy phase measurements. A collaborative algorithm was designed to optimize the interplay between the optical delay line and the fiber stretcher, utilizing a proportional-integral-derivative (PID) control algorithm to enhance adjustment precision. A Field Programmable Gate Array (FPGA) served as the core interface converter, facilitating data communication and real-time phase information acquisition. Experimental results demonstrated significant improvements in phase stability, with average phase deviation reduced from 1374.104 fs to 15.782 fs, showcasing the effectiveness of the proposed system in achieving high precision and stability in phase control. This research provides a solid foundation for future advancements in timing systems for high-frequency reference signals. [ABSTRACT FROM AUTHOR]

Wind farms with type IV wind turbines from various manufacturers are being massively put into operation. These wind turbines comply with the requirements of the grid codes of the countries where they are designed and/or manufactured, but do not factor in the specific features of the distribution networks of other countries to which they are connected. The study at issue involves a comparative analysis of the requirements of grid codes of different countries for the stable operation of wind turbines under standard disturbances. The low voltage ride through (LVRT) characteristic makes it possible to prevent wind turbine shutdowns in case of short-term voltage dips of a given depth and duration. The calculations of transient processes indicate that wind turbines may not meet the requirements of the grid code of a particular country for their stable operation. As a result, standard disturbances will block the reactive current injection and the wind turbine will be switched off. This is often caused by the relay protection devices with a time delay of 1–2 s, which are used in distribution networks and implement the functions of long-range redundancy. Excessive shutdowns of wind turbines lead to emergency rises in the loads for the generating units of conventional power plants, aggravating the post-accident conditions and disconnecting consumers of electricity. This article presents a method for checking the LVRT characteristic settings for compliance with the technical requirements for wind turbines. To prevent wind turbine outages, one should either change the configuration of the LVRT characteristic, upgrade the relay protection devices in the distribution network adjacent to the wind farm, or implement group or individual technical solutions at the wind farm. The performance of the proposed technical solutions is confirmed by the calculations of transient processes. [ABSTRACT FROM AUTHOR]

We focus on dual-user operation, where two users control a single remote robot equipped with a force sensor using haptic interface devices. We employ a cooperative work in which the two users control the remote robot to collaborate with remote robot systems with force feedback to carry an object. By measuring the force acting upon the object, we aim to better understand the underlying mechanisms by which the user with lower network latency can help the other user, as observed in our previous work. We notice that with increasing network delays, the force exerted on the object tends to intensify, indicating that it becomes more challenging for users to operate the remote robot effectively as network delays increase. We also measure the force applied to the object by changing the network delays between the remote robot and the two users to clarify why the user with the lower network delay can assist the other user. We find that when the total network delay is the same, the average force magnitude and the average maximum force magnitude remain nearly identical. This is because, despite the challenges faced by the user with the larger network delay, the user with the smaller delay can operate the remote robot more easily and assist the other user. In order to reduce the force acting upon the object, we propose an enhancement method for the robot position control, which determines the position of the remote robot arm while accounting for network delay, and investigate the effects by experiment. Experimental results demonstrate that our proposed method is effective and can reduce the applied force. This is because the proposed method adjusts the ratio between the user with the lower delay and the user with the higher delay. The user with the lower delay can operate the remote robot more easily and respond to it more quickly. Our findings and proposed method can be useful in improving work accuracy and operability when designing a remote robot system with force feedback for applications. [ABSTRACT FROM AUTHOR]

This study comprehensively assesses various recurrent neural networks (RNNs) for decoding the elbow angle from electromyogram (EMG) signals, a crucial aspect in myoelectric interfaces. EMG signals from the shoulder girdle and arm were recorded during goal-directed reaching movements, and linear envelopes were continuously mapped to the elbow angle by three RNN architectures: nonlinear autoregressive exogenous (NARX), Elman, and long-term short memory (LSTM). All three approaches effectively captured the complex dynamics of the multi-input to a single-output regression problem. Regarding within-subject variability, the NARX, Elman, and LSTM demonstrated superior accuracy and robustness compared to dynamic feedforward neural networks like time-delay neural networks. Notably, there was no statistically significant distinction among NARX, Elman, and LSTM estimation performances. Elman and LSTM exhibited an advantage in decoding latent information dependencies through their context layers, leading to improved estimation performance in inter-subject variability analysis, particularly with increased training data volume and variability. Furthermore, the LSTM, with its complex architecture capable of learning long-term temporal dependencies, exhibited the highest performance among the considered RNNs. Consequently, selecting the optimal RNN structure is recommended based on the complexity of the data at hand. The RNN-based decoding model holds potential applications in prosthetics, robotic assistants, and exoskeletons, enabling intention detection and real-time assessment of active rehabilitation progress. [ABSTRACT FROM AUTHOR]

Over the past few decades, extensive research has been devoted to the design of artificial reverberation algorithms aimed at emulating the room acoustics of physical environments. Despite significant advancements, automatic parameter tuning of delay-network models remains an open challenge. We introduce a novel method for finding the parameters of a feedback delay network (FDN) such that its output renders target attributes of a measured room impulse response. The proposed approach involves the implementation of a differentiable FDN with trainable delay lines, which, for the first time, allows us to simultaneously learn each and every delay-network parameter via backpropagation. The iterative optimization process seeks to minimize a perceptually motivated time-domain loss function incorporating differentiable terms accounting for energy decay and echo density. Through experimental validation, we show that the proposed method yields time-invariant frequency-independent FDNs capable of closely matching the desired acoustical characteristics and outperforms existing methods based on genetic algorithms and analytical FDN design. [ABSTRACT FROM AUTHOR]

Summary: Despite the performed progressive research work, the interpretation of the negative group delay (NGD) function remains not familiar to non‐specialist design and fabrication circuit engineers. The functionality misunderstanding limits the NGD circuit applications compared to other classical electronic functions. The present paper deals with the design of a tunable circuit by operating with positive and negative delay behaviors. The topology of the tunable circuit by using a low‐pass (LP) type NGD circuit is described. The design formulas for calculating the circuit resistor and capacitor parameters from the desired delay are expressed. The design feasibility of the tunable circuit composed of LP‐NGD cell and RC‐circuit is validated with a proof‐of‐concept (PoC) implemented on a test board. Two different signals with pulse and arbitrary waveforms having tens‐milliseconds duration were considered during the validation tests. As expected by tuning a varistor from 0.4 kΩ to 1 kΩ, the negative delay behavior varying from about −0.4 ms was verified thanks to the time‐advanced effect due to the LP‐NGD property. Then, the output signal delay was observed to become positive when the varistor was tuned from 1 kΩ to 3 kΩ. [ABSTRACT FROM AUTHOR]

For ultra-high-speed digital transmission, required by 5G/6G communications, ultra-wideband common-mode rejection (CMR) structures with autonomous phase-balancing capability are proposed. Common-mode noise, caused by phase and amplitude unbalances, is one of the most undesired disturbances affecting modern digital circuits. According to the circuit design guides with a typically used differential line (DL) for high-speed digital transmission, common-mode rejection is achieved using CMR filters, and the unbalanced phase, caused by a length difference between the two signal lines of a DL, is compensated by inserting an additional delay line. However, due to nonlinear phase interactions between the two DLs and unbalanced electromagnetic (EM) interferences, the conventional compensation method is frequency-limited at around 10 GHz. To significantly enhance the common-mode rejection level and extend the phase recovery bandwidth, the proposed CMR structure utilizes a planar balanced line (BL), such as a coplanar stripline (CPS) or a parallel stripline (PSL), along with additional conductor strips arranged laterally near the BL. To demonstrate the performance of the proposed BL-based CMR structures, various types of CMR structures are fabricated, and the measurement results are compared with the 3D EM simulation results. As a result, it is proven that the proposed BL-based CMR structures have the capability to reject the common-mode noise with suppression levels of more than 10 dB and to simultaneously recover the phase balance from near DC to over 40 GHz. [ABSTRACT FROM AUTHOR]

Outbreaks of viral infectious diseases in humans and animals remain one of the global problems of our time. Therefore, one of the most popular areas in applied microbiology is the development of fast and sensitive methods for determining viruses, including those based on biosensor analysis methods. The promise of acoustic sensor systems for detecting viruses is described in this work. The optimal capabilities of electroacoustic sensors in detecting viruses, the possibility of conducting analysis in the presence of interfering factors (viral particles and microflora), and the repeated use of sensors are shown. The promise of using acoustic sensors to determine viruses in microbiology, medicine, and veterinary medicine is demonstrated. [ABSTRACT FROM AUTHOR]

Aiming at the issues of control delay and circuit parameter mismatch in three-phase modular multilevel converters (MMCs), this paper proposes a model assisted extended state observer-based deadbeat predictive current control (MAESO-based DPCC) strategy to regulate the AC-side current and internal circulating current. The model assisted ESO (MAESO) is employed to estimate the predicted values of the d- and q-axis components of the AC-side current, the internal circulating current, and system disturbance caused by the other certain and uncertain factors (including circuit parameter changes) of MMC at the time instant k + 1, and the required control input at the time instant k + 1 is then calculated based on the deadbeat control principle. The proposed control strategy not only maintains excellent steady-state performance and fast dynamic response characteristics similar to those of the traditional deadbeat predictive current control (DPCC) strategy but also has stronger robustness in the case of circuit parameter changes. The proposed control strategy was ultimately compared with the traditional DPCC strategy via experiments, and the experimental results verify the feasibility and effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

The sound produced by vehicles driving on roadways constitutes one of the dominant noise sources in urban areas. The impact of traffic noise on human activities and the related investigation on modeling, assessment, and abatement strategies fueled the research on the simulation of the sound produced by individual passing vehicles. Simulators enable in fact to promote a perceptual assessment of the nature of traffic noise and of the impact of single road agents on the overall soundscape. In this work, we present TrafficSoundSim, an open-source framework for the acoustic simulation of vehicles transiting on a road. We first discuss the generation of the sound signal produced by a vehicle, represented as a combination of road/tire interaction noise and engine noise. We then introduce a propagation model based on the use of variable length delay lines, allowing to simulate acoustic propagation and Doppler effect. The proposed simulator incorporates the effect of air absorption and ground reflection, modeled via complex-valued reflection coefficients dependent on the road surface impedance, as well as a model of the directivity of sound sources representing the passing vehicles. The source signal generation and the propagation stages are decoupled, and all effects are implemented using finite impulse response filters. Moreover, no recorded data is required to run the simulation, making the framework flexible and independent on data availability. Finally, to validate the framework capability to accurately simulate passing vehicles, a comparison between synthetic and recorded pass-by events is presented. The validation shows that sounds generated with the proposed method achieve a good match with recorded events in terms of power spectral density and psychoacoustics metrics as well as a perceptually plausible result. [ABSTRACT FROM AUTHOR]

This paper aims to formulate a class of nonlinear hybrid stochastic time-delay neural networks (STDNNs) with Lévy noise. Specifically, the coefficients of networks grow polynomially instead of linearly, and the time delay of given neural networks is non-differentiable. In many practical situations, nonlinear hybrid STDNNs with Lévy noise are unstable. Hence, this paper uses feedback control based on discrete-time state and mode observations to stabilize the considered nonlinear hybrid STDNNs with Lévy noise. Then, we establish stabilization criteria of H ∞ stability, asymptotic stability, and exponential stability for the controlled nonlinear hybrid STDNNs with Lévy noise. Finally, a numerical example illustrating the usefulness of theoretical results is provided. [ABSTRACT FROM AUTHOR]

The combination of speed and resolution is a fundamental figure of merit for Fourier transform spectroscopy. Here, we show that, by combining a fast rotational delay line with a strongly modulated quantum cascade laser (QCL), it is possible to perform broadband spectroscopy over a range of 175 cm−1, with a total effective integration time of about 6 s and a resolution of 0.03 cm−1. Remarkably, even though the resolution of the measurement is limited by the source, the interleaving technique can still be applied when the QCL is not in a frequency comb regime, considerably broadening the bandwidth of the instrument. [ABSTRACT FROM AUTHOR]

In this paper we investigate the application of phase-shifting digital holography for the real-time characterization of electromagnetic sources in the THz frequency range. We use an off-the-shelf terahertz detector array composed of 64 × 64 power-sensitive pixels, over an area of 96 mm × 96 mm , to record intensity interferograms cast between the coherent radiation emitted from a reference source and an unknown antenna under test. This approach parallelizes the acquisition process with respect to conventional near-field point scanning methods, reducing the measurement time by orders of magnitude. In our system, the measurement time is limited only by the refresh rate of the detector array and the speed of a delay line stage that is used to phase-shift the reference wave. As a proof-of-principle demonstration, we map the 2D near-field distribution and estimate the far-field radiation pattern emitted by a plano-convex PTFE spherical lens antenna illuminated by a diagonal horn at 290 GHz frequency with ∼ 1 Hz refresh rate. [ABSTRACT FROM AUTHOR]

A fundamental aspect in the evolution of Time-to-Digital Converters (TDCs) implemented within Field-Programmable Gate Arrays (FPGAs), given the increasing demand for detection channels, is the optimization of resource utilization. This study reviews the principal methodologies employed for implementing low-resource TDCs in FPGAs. It outlines the foundational architectures and interpolation techniques utilized to bolster TDC performances without unduly burdening resource consumption. Low-resource Tapped Delay Line, Vernier Ring Oscillator, and Multi-Phase Shift Counter TDCs, including the use of SerDes, are reviewed. Additionally, novel low-resource architectures are scrutinized, including Counter Gray Oscillator TDCs and interpolation expansions using Process–Voltage–Temperature stable IODELAYs. Furthermore, the advantages and limitations of each approach are critically assessed, with particular emphasis on resolution, precision, non-linearities, and especially resource utilization. A comprehensive summary table encapsulating existing works on low-resource TDCs is provided, offering a comprehensive overview of the advancements in the field. [ABSTRACT FROM AUTHOR]

This paper describes a study on speaker recognition using the ECAPA-TDNN architecture, which stands for Extended Context-Aware Parallel Aggregations Time-Delay Neural Network. It utilizes X-vectors, a method for extracting speaker features by converting speech into fixed-length vectors, and introduces a squeeze-and-excitation block to model dependencies between channels. In order to better explore temporal relationships in the context of speaker recognition and improve the algorithm's generalization performance in complex acoustic scenarios, this study adds input gates and forget gates to the ECAPA-TDNN architecture, combining them with CIFG (Convolutional LSTM with Input and Forget Gates) modules. These are embedded into a residual structure of multi-layer aggregated features. A sub-center Arcface, an improved loss function based on Arcface, is used for selecting sub-centers for subclass discrimination, retaining advantageous sub-centers to enhance intra-class compactness and strengthen the robustness of the network. Experimental results demonstrate that the improved ECAPA-TDNN-CIFG in this study outperforms the baseline model, yielding more accurate and efficient recognition results. [ABSTRACT FROM AUTHOR]

Model order reduction technique provides an effective way to reduce computational complexity in large-scale circuit simulations. This paper proposes a new model order reduction method for delay circuit systems based on Hermite expansion technique. The presented method consists of three steps i.e., first the delay elements are approximated using the recursive relation of Hermite polynomials, then in the second step, the reduced order is estimated for the delay circuit system using a delay truncation in the Hermite domain and in the third step, a multi-order Arnoldi process is computed for obtaining the projection matrix. In the following, the reduced order delay circuit model is obtained by the projection matrix. Moment matching and passivity properties of the reduced circuit system are also analyzed. Two circuit examples with delay components are performed to verify the effectiveness of the proposed MOR approach. [ABSTRACT FROM AUTHOR]

Summary: This letter presents a design method for dual‐band filtering phase shifters, which is based on E‐type networks. The dual‐band filtering function and different predetermined phase shift values are realized by E‐type networks and two delay lines. The dual‐band bandwidth and frequency ratio can be adjusted. Moreover, the dual‐band phase‐shift bandwidth has been extended. Finally, a dual‐band filtering phase shifter with simple structure and good filtering characteristics is fabricated and measured, which can provide 90 ± 5° and 225 ± 5° phase shifts at 1.75–2.58 GHz and 4.38–5.78 GHz, respectively. All results exhibit a good agreement between the electromagnetic (EM) simulation and measurement results. [ABSTRACT FROM AUTHOR]

Here, we report on a simplified laser frequency noise measurement technique employing an acousto-optic modulator, a delay line, and a real-time oscilloscope. The technique is a slight modification of the typical delayed heterodyne method. Instead of using a swept frequency spectrum to analyze the laser emission spectrum, the waveform captured on a real-time oscilloscope is used to directly calculate the laser frequency noise. The oscilloscope bandwidth and sampling requirements can be kept modest by choosing a modulator driven at a few hundred megahertz, making this technique attractive for a large number of laboratories. We show the frequency noise measurements of two different lasers with linewidths at 2.7 kHz and 2 MHz. We took the opportunity to investigate the noise floor of the frequency noise measurement system, and we found that the noise floor of the frequency noise measurement depends on the power level of the laser that is being characterized, with the kilohertz linewidths laser requiring more power to reduce the noise floor to acceptable levels. [ABSTRACT FROM AUTHOR]

As a new planar electrostatic (or, in a better word, quasi-electrostatic) waveguide, the characteristics of electrostatic bulk waves guided by a slab of metallic nanowire-based hyperbolic metamaterials are studied. The dispersion relation of the waves is obtained using the zig-zag ray approach based on the stationary-phase method which is the same as the result obtained from the field analysis. Also, we present a description for the investigation of the group velocity and associated group delay time of electrostatic bulk modes of the system. The analytical results based on the zig-zag ray approach show the group delay is produced partly at the boundaries of the slab and partly inside the slab. The former is not dependent on the order of the mode and can be neglected compared with the latter in the neighborhood of the frequency of resonance where electrostatic wave devices are usually operated. [ABSTRACT FROM AUTHOR]

We provide a comprehensive technical analysis of the data acquisition process with oscillating delay lines for Terahertz-time domain spectroscopy. The utilization of these rapid stages, particularly in high-repetition-rate systems, is known to enable an effective reduction of noise content through averaging. However, caution must be exercised to optimize the data averaging process, with the goal of significantly optimizing the dynamic range (DR) and signal-to-noise ratio (SNR). Here we discuss some pitfalls to avoid and the effect of improper data handling on the dynamic range obtainable. A free and open-source program, called parrot (Processing All Rapidly & Reliably Obtained THz-traces), is provided alongside this publication to overcome the discussed pitfalls and facilitate the acceleration of experimental setups and data analysis, thereby enhancing signal fidelity and reproducibility. [ABSTRACT FROM AUTHOR]

A novel flat negative group delay circuit is proposed. The flatter negative group delay is achieved, and the insertion loss is reduced. The circuit structure consists of a resistor R1 series connected with a capacitor C1 and inductor L1 in parallel, followed by a capacitor C2 and inductor L2 in parallel, and finally connected in series with a capacitor C3 and inductor L3. The analysis design equation is provided. The effects of different component values on circuit flatness and bandwidth are analyzed. According to this design method, a flat negative group delay circuit is designed and fabricated. The simulation and measurement results are basically consistent. It has good flat negative group delay characteristics, with a group delay fluctuation of 3%, a group delay value of −1.02 ns, and an insertion loss of 7 dB. The feasibility of the design method is verified. [ABSTRACT FROM AUTHOR]

Necessity of bandwidth requires the effective use of it for high speed data transmission and faster read/write operation in memory cells. In this paper the transfer function expressions for RC interconnect line is presented for resistive load. The line delay, bandwidth and step response for current and voltage mode signalling is formulated. The current mode and voltage mode signalling provides the 3-dB bandwidth of 6.8 GHz and 3.1 GHz, respectively. An interconnect line modelled as either RLC or RC line depending upon input signal rise time, damping, and range of interconnect length with significant inductance effect is investigated for global interconnect lines. Low swing for column bit line in memory architectures is very important and estimated in terms of dc coefficients. For RC global interconnect of 10 mm, a swing of 0.382 V is obtained for current mode signalling, when a power supply of 1.8 V is applied to the network. DC coefficient and steady state value has been obtained which is significant for power computation on column bit line. It is also analytically validated by SPICE and MATLAB simulations. [ABSTRACT FROM AUTHOR]

To realize transparent monitoring and resilience improvement of low- voltage distribution network, both the data acquisition scope and frequency have been greatly expanded. Cloud-edge collaboration leverages the edge server's real-time response capabilities and the cloud server's robust data processing power to enhance the performance of high-frequency data acquisition processing. Nonetheless, it continues to confront challenges such as the entanglement of optimization variables, the presence of uncertain information, and a lack of awareness regarding acquisition frequencies. In this paper, we propose a machine learning-based cloud-edge collaborative data processing optimization algorithm to minimize the weighted sum of data processing delay and device energy consumption for distribution network resilience improvement. The joint optimization problem is decoupled into device-edge data offloading subproblem and edge-cloud data splitting subproblem, which are solved by the proposed upper confidence bound (UCB) based frequency-aware device-edge data offloading optimization algorithm and the exponential-weight algorithm for exploration and exploitation (EXP3) based edge-cloud data splitting optimization algorithm, respectively. Simulation results show that the proposed algorithm is superior to existing algorithms in performances of energy consumption and total processing delay. [ABSTRACT FROM AUTHOR]

Aiming to address the timing skew mismatch in the time‐interleaved analog‐to‐digital converter (TIADC) system, this paper presents a timing skew mismatch calibration method based on a back propagation (BP) neural network optimized by an adaptive genetic algorithm (AGA). In this paper, a trained BP neural network is used to detect the timing skew mismatch in the TIADC system, and the variable delay line is used to calibrate it. In this paper, AGA is used to optimize the BP neural network, accelerating its training speed and improving the detection accuracy of timing skew mismatch in the system. The proposed approach boasts superior detection speed and accuracy compared to other methods. In this paper, an 18‐bit 1GS/S 4‐channel TIADC system is simulated and the timing skew mismatch in the system is corrected. Simulation results show that the proposed calibration method has fast detection speed, high detection accuracy, and calibration accuracy. After completing the timing skew mismatch correction, the performance of the TIADC system is dramatically improved. The effective number of bits (ENOB) of the system increases by 9.5 bits, and the spurious‐free dynamic range (SFDR) increases by 59.9 dB. [ABSTRACT FROM AUTHOR]

Phase alignment of periodic events between multiple systems is required in multiple fields and applications. Most of the existing solutions focus on either low frequency and relatively low accuracy or high complexity, high accuracy and precision. In contrast, this work aimed to develop an intermediate solution, supporting high frequencies and relatively high accuracy and precision, with relatively low complexity. A hypothetical concept and mathematical model is presented with a hardware test implementation based entirely on FPGA resources. Deliberate resource selection and utilization enables a significant simplification of calculations and, as a result, a reduction in logic resource utilization. The proposed concept was implemented and verified using the AMD/Xilinx Artix 7 35T FPGA platform. [ABSTRACT FROM AUTHOR]

This work demonstrates the use of an erbium-doped fiber amplifier (EDFA), a tunable bandpass filter (TBF), and a tunable delay line interferometer (TDLI) to form a ring laser that produces multi-format, multi-wavelength laser beams. The TDLI serves as the core of the proposed laser generation system. TDLI harnesses the weak Fabry–Pérot (FP) interferences generated by its built-in 50/50 beamsplitter (BS) with unalterable filtering characteristics and the interferences with free spectral range (FSR) adjustable from each of its two outputs with nearly complementary phases to superpose and generate a variable interference standing wave. The interferometric standing wave and weak FP interferences are used to form a spatial-hole burning to promote the excitation of multi-format and multi-wavelength lasers. The proposed system enables dual-wavelength spacing ranging from 0.3 nm to 3.35 nm, with a switchable wavelength position at approximately 1527 nm to 1535 nm, providing flexible tunability. [ABSTRACT FROM AUTHOR]

The time-to-digital converter (TDC) implemented in a field-programmable-gate-array has garnered widespread attention due to its flexibility and high-performance capabilities. However, issues such as non-uniformity, the bubble in the tapped delay line, and the presence of certain ultra-wide delay units can significantly compromise the precision and nonlinearity of the TDC. In this paper, we propose a high-precision TDC in an Elitestek Ti60 FPGA, effectively eliminating the adverse effects of non-uniformity, the bubble, and certain ultra-wide delay units. The TDC is constructed with a 318-stage delay chain and operates at a low system clock frequency of 150 MHz. The least significant bit (LSB) of the TDC is 21.92 ps. The differential nonlinearity (DNL) is between (−0.976, 1.615) LSB and the integral nonlinearity (INL) is between (−1.446, 2.678) LSB. The TDC achieves a root-mean-square error of 14.783 ps when utilized for measuring various time intervals. [ABSTRACT FROM AUTHOR]

In this study, a high-gain broadband circularly polarized crossed dipole antenna is designed. This antenna utilizes two pairs of cross dipoles and a pair of phase delay lines to form circularly polarized radiation. Open-circuit stubs are symmetrically loaded on the four arms of these dipole pairs to introduce new circularly polarized resonating frequencies. Additionally, a symmetrically positioned rectangular ring patch is introduced directly beneath the cross dipoles to generate the third circularly polarized resonating frequency, thereby enhancing the axial ratio bandwidth of the antenna symmetrically. Furthermore, metal posts are symmetrically loaded at the four right angles of the rectangular ring patch to augment the antenna gain, maintaining the overall symmetrical balance crucial for optimal circularly polarized radiation performance. This symmetric design ensures that the antenna achieves a 3dB axial ratio bandwidth of 29.2% (1.9–2.55 GHz) and sustains a gain of 7.5 dB within the passband, showcasing excellent circularly polarized radiation attributes. [ABSTRACT FROM AUTHOR]

This Letter demonstrates the use of long-lifetime NO fluorescence for molecular tagging velocimetry (MTV) with (1 + 1) resonant-enhanced multiphoton ionization (REMPI) scheme, utilizing a single laser beam in a detonation-driven hypersonic shock tunnel. The Q1 branch of the NO A ← X (0, 0) transition was excited using radiation near 226.256 nm. It was determined that (1 + 1) REMPI of NO generates long lifetime fluorescence, and this observation is consistent with the findings reported by Jiang et al. [Opt. Lett. 49, 1297–1300 (2024)] and Leonov et al. [Opt. Lett. 49, 426–429 (2024)]. Single-shot tagged lines at microsecond delay times were obtained in a Ma6.9 hypersonic freestream flow using a long focal length lens. The measured average velocity of 3477 m/s agrees well with the simulation result. [ABSTRACT FROM AUTHOR]

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A novel compact broadband negative group delay (NGD) circuit with flatness and bandwidth enhancement is presented. The presented negative group delay circuit (NGDC) consists of a high-impedance transmission line connected by two resistors, which are linked together with two coupled lines and a low-impedance transmission line. The flatness of the NGD is enhanced by tuning the characteristic impedance of the transmission lines. In order to verify the method, a compact broadband NGDC with a size of 29.4 mm × 58.1 mm (0.14 λg × 0.29 λg) is designed, fabricated, and measured at the center frequency of 1.0 GHz. The measured results show that an NGD time of −0.49 ns at the center frequency is obtained with return loss and insertion loss of 35.0 dB and 18 dB, respectively. And, the flat-NGD bandwidth reaches 509 MHz (50.9%) over 0.766 to 1.275 GHz with 19% group-delay fluctuation. [ABSTRACT FROM AUTHOR]

Directed evolution is a powerful technique for creating biomolecules such as proteins and nucleic acids with tailor-made properties for therapeutic and industrial applications by mimicking the natural evolution processes in the laboratory. Droplet microfluidics improved classical directed evolution by enabling time-consuming and laborious steps in this iterative process to be performed within monodispersed droplets in a highly controlled and automated manner. Droplet microfluidic chips can generate, manipulate, and sort individual droplets at kilohertz rates in a user-defined microchannel geometry, allowing new strategies for high-throughput screening and evolution of biomolecules. In this review, we discuss directed evolution studies in which droplet-based microfluidic systems were used to screen and improve the functional properties of biomolecules. We provide a systematic overview of basic on-chip fluidic operations, including reagent mixing by merging continuous fluid streams and droplet pairs, reagent addition by picoinjection, droplet generation, droplet incubation in delay lines, chambers and hydrodynamic traps, and droplet sorting techniques. Various microfluidic strategies for directed evolution using single and multiple emulsions and biomimetic materials (giant lipid vesicles, microgels, and microcapsules) are highlighted. Completely cell-free microfluidic-assisted in vitro compartmentalization methods that eliminate the need to clone DNA into cells after each round of mutagenesis are also presented. [ABSTRACT FROM AUTHOR]

A novel multi‐band pass negative group delay circuit has been designed and proposed. The circuit consists of three types of components: capacitance, inductance, and resistance. An n‐order bandpass negative group delay circuit was analyzed and presented, and taking a three‐frequency bandpass negative group delay circuit as an example, the influence of different component values on the circuit group delay and insertion loss was analyzed. The actual test results of this circuit are consistent with the simulation results, and it can achieve the function of a multi‐bandpass circuit. In actual testing, the circuit frequencies with negative group delay are 49, 82, and 102 MHz, with corresponding group delay values of −2.177, −2.058, and −1.903 ns and corresponding insertion loss values of −5.810, −5.835, and −5.866 dB. [ABSTRACT FROM AUTHOR]

In image processing, the noticeable variations of the image can be found using the edge detection process. This edge detection process facilitates to identify placement and edges of an object. The Sobel edge detection process is preferred since it is simple and more noise immune. Sobel edge detection calculates gradients of a pixel in horizontal and vertical directions concerning neighboring pixels. The gradients absolute quantities are computed, added, and matched to a threshold for finding whether the pixel is an edge pixel or not. In this paper, the Sobel edge detection system VLSI architecture is designed which consumes less power by using the arithmetic blocks like Brent Kung adders. The source image of different resolutions is taken to perform Sobel edge detection and implemented using various FPGA devices by analyzing power dissipation, delay and device utilization summary. Then, simulation, synthesis processes are performed and finally, power analysis is performed using XPower Analyzer of Xilinx ISE software. [ABSTRACT FROM AUTHOR]

The most promising emerging technology that can reduce the power, area and delay in digital circuits is Quantum-dot Cellular Automata (QCA) technology. The Serial Input-Serial Output (SISO) Shift Register (SR) is a basic component in digital circuits. The SISO SR can be designed using two methods in the QCA technology, directly mapping circuits from the CMOS technology and using the inherent capability of the QCA technology. This paper presents and evaluates the new n -bit QCA SISO SR that not only uses the inherent capability of QCA technology but also has a regular architecture. The proposed n -bit SISO SR is developed based on the building block, which is designed in this paper. In addition, the developed QCA SISO SR has coplanar architecture and it has the ability to correct or change data. The proposed n -bit SISO SR is evaluated for 3, 4 and 5 bits using QCADesigner- E. The results demonstrate that the designed circuits for 3-, 4- and 5-bit QCA SISO SRs require 68 (0.06 μ m 2) , 92 (0.08 μ m 2) and 116 (0.09 μ m 2) cells (area), respectively. The comparison demonstrates that the developed QCA SISO SRs have advantages in comparison to other QCA SISO SR circuits. An efficient architecture has been presented to design novel architecture for n-bit QCA SISO SRs. The designed architecture has coplanar architecture. It not only has regular architecture, but also uses hybrid of inherent capability of the QCA and CMOS technology. The comparison of the obtained results demonstrates that the designed SRs have advantages in comparison with other SRs in the QCA technology. [ABSTRACT FROM AUTHOR]

The resolution of time-to-digital converters (TDC) is one parameter that will define its efficiency. This research demonstrates a 5.4 ps TDC with anti-PVT-variation implemented in 90-nm CMOS technology. The proposed converter uses a two-step architecture. The first stage is a Buffer Delay Line (BDL) to acquire a wide dynamic range characteristic. The second stage that will provide a higher resolution is Vernier delay line which receives the start and stop signals from the edge detector. A PVT (process, voltage, temperature) corner detector is equipped in the proposed TDC to resist the PVT variation. The proposed TDC's post-layout simulation results achieve a delay variation of 2 ps and a resolution of 5.4 ps, and an acceptable dynamic range of 890 ps. The INL and DNL attained a value of 0.8 and −1 LSB from the simulations. The proposed TDC attains the best FOM based on post-layout simulations with a value of 0.177, which makes it superior to all prior designs. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a multiphase digital control called digital integration constant on‐time (DICOT) control is proposed, which applies the concept of signal accumulation, solves the drawbacks of ripple‐based digital COT control that the switching frequency and transient performance are affected by the A/D sample delay and sampling noise. Besides, the multiphase interleaving approach of the proposed DICOT control is well‐suitable for digital control and no higher calculation frequency is required compared to single‐phase. In the aspect of the current balance, almost all existing researches work on analog COT current balance scheme and few works are investigating the resolution improvement of digital COT current balance. In this paper, the current balance model of multiphase COT control is derived and can be applied in the Buck system with an arbitrary number of phases, the delay‐line‐based high‐resolution COT current balance scheme is proposed to enhance the control resolution. Finally, the two‐phase DICOT control is tested on the multiphase Buck system, the transient performance is tested of 100 A load step with the slew rate of 1000 A/μs, and the voltage undershoot and overshoot are 20 and 36 mV, respectively. The current balance is tested and the errors are 0.01% and 0.11% at the light and heavy loads, respectively. [ABSTRACT FROM AUTHOR]

The design of arrays capable of receiving wideband signals differs from arrays that can only receive narrowband signals. These arrays must be able to receive signals with an instant bandwidth of several GHz across the entire operating frequency, such as High‐Resolution Radars or Terahertz in 6G communication systems. In these arrays, using a time delay line structure leads to an increase in beamformer coefficients, resulting in high computational complexity. This poses a challenge for beamforming in wideband systems. Additionally, classic Wideband beamformers face other factors, such as poor performance in the presence of input direction of arrival error, array calibration error, and requiring too many snapshots to reach the steady state of the beamformer. Therefore, the robustness of wideband adaptive beamforming using deep unfolding model‐based technique is focused on, which has not been discussed before. The advent of deep unfolding, an innovative technique, amalgamates iterative optimization approaches with elements of neural networks. The aim is to deftly maneuver through various tasks across disciplines such as machine learning, signal and image processing, and telecommunication systems. Also, the network training method is done to become more robust against the mentioned factors. In the proposed structure, the constraints of the previous methods have been evaluated. It is observed to have better performance compared to other classic algorithms. Also, with the investigations of the proposed method with other conventional deep learning methods, it was observed that in some cases the proposed structure performance is equal to the conventional deep learning method and sometimes better. [ABSTRACT FROM AUTHOR]

We numerically propose a vertically coupled ring resonator with a high extinction ratio and tunable group delay based on Silicon (Si)–Indium Tin Oxide (ITO) heterojunction. The vertically coupled ring and bus waveguide configuration offers several advantages including, improved coupling efficiency, and reduced propagation losses, which allows for efficient coupling between the Si-bus waveguide and the Si–ITO ring, leading to stronger light–matter interaction and enhanced light transmission. The Si–ITO heterojunction within the ring resonator enables electrically varying carrier concentration of ITO, thereby reaching the epsilon-near-zero (ENZ) region. The achievement of the ENZ region leads to enhanced optical absorption and improved device performance. The proposed device exhibits a high extinction ratio of 20.5 dB. Moreover, the voltage-dependent group delay of the device exhibited a significant variation of 29 psec when the applied voltage is varied within the range of − 4 V to 4 V. The voltage-tunable vertically coupled Si–ITO heterojunction-based ring modulator offers a promising platform for integrated photonics, with potential applications in optical communication, signal processing, and sensing. [ABSTRACT FROM AUTHOR]

In view of the challenges faced by cotton dibbler in Xinjiang under high-speed operation, a novel crawler-type delayed hole-forming device has been designed to address the seed throwing and floating issues in high-speed cotton dibbling in Xinjiang, enhancing the duck bill's performance. This mechanism increases the sowing speed to 6 km/h by extending the duck bill horizontally. Utilizing agronomic principles, the mechanism's layout and key components were optimized for efficient hole-forming. DEM and multi-body dynamics simulations were employed to analyze the motion, focusing on the fixed the tilt angle of the duck bill (A), the depth of the duck bill hole-forming into the soil (B), and the angle of rotation of the moving duck bill (C) as factors affecting hole dimensions (longitudinal length of hole Y1 and hole-forming depth of cotton seed hole Y2). Quadratic regression test using RecurDyn-EDEM coupling identified optimal parameter settings for maximum hole-forming performance. When A was 2.4°, B was 42.4 mm, and C was 30.5°, the performance of the hole-forming was the best. Under the optimal parameter combination, the bench verification test was carried out. The error between the bench verification results and the simulation results is small, indicating that the model has high accuracy. The average opening time of the duck bill at a speed of 6 km/h is 0.45 s, which is much longer than the time required for cotton seeds to fall from the duck bill (0.11 s). It meets the requirements of high-speed cotton planting in China and facilitating advancements high-speed planter technology. [ABSTRACT FROM AUTHOR]

This paper presents a compact wideband circularly polarized cross-dipole antenna with a low-pass filter response. It consists of two pairs of folded cross-dipole arms printed separately on both sides of the top substrate, and the two dipole arms on the same surface are connected by an annular phase-shifting delay line to generate circular polarization. A bent metal square ring and four small metal square rings around the cross-dipoles are employed to introduce new resonant frequencies, effectively extending the impedance and axial-ratio bandwidth. Four square patches printed on the middle substrate are connected to the ground plane by the vertical metal plates in order to reduce the antenna height. Thus, a compact wideband circularly polarized antenna is realized. In addition, a transmission zero can be introduced at the upper frequency stopband by the bent metal square rings, without using extra filter circuits. For verification, the proposed model is implemented and tested. The overall size of the model is 90 mm × 90 mm × 33 mm ( 0.37 λ 0 × 0.37 λ 0 × 0.14 λ 0 ; λ 0 denotes the center operating frequency). The measured impedance bandwidth and 3 dB axial-ratio (AR) bandwidth are 53.3% and 41%, respectively. An upper-band radiation suppression level greater than 15 dB is realized, indicating a good low-pass filter response. [ABSTRACT FROM AUTHOR]

The structure of arrays capable of receiving wideband signals differs from arrays which can only receive narrowband signals. These arrays should be capable of receiving several GHz instant bandwidth signals over the entire operating frequency, like High Resolution Radars or Terahertz in 6G communication systems. In these arrays, the number of beamformer coefficients increase due to using a time delay line structure, hence leading to a high computational complexity. This is one of the challenges of beamforming in wideband systems. Additionally, there are other factors in classic Wideband beamformers. These factors include poor performance against input DOA (direction of arrival) error, array calibration error, and too many snapshots to reach the steady state of the beamformer. Therefore, this paper focuses on the robustness of beamforming using deep learning technique, which has not been discussed before. The basis of network design is convolutional layers. Two different proposed approaches have been proposed to obtain optimal structure. In the first approach, appropriate values of hyperparameters are estimated, whereas the network model is selected in the second approach. Also, the network training method is done to become more robust against the mentioned factors. In the proposed structures, the constraints of the previous methods have been evaluated. The proposed structure is shown to have a superior performance when compared with other existing algorithms. In addition, the matrix of signal samples is replaced with the covariance matrix at the network's input, so the calculation time is significantly improved compared to the previous methods. [ABSTRACT FROM AUTHOR]