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For the first time, a rapid method was proposed to determine the susceptibility of Escherichia coli cells to antibiotics by the example of ampicillin by using a biological sensor based on a slot mode in an acoustic delay line. It has been established that an indicator of the antibiotic activity to microbial cells is the difference between the recorded sensor’s signal before and after exposure cells with antibiotic. The depth and frequency of the peaks of resonant absorption in the frequency dependence of the insertion loss of sensor varied after adding an antibiotic with different concentrations to the microbial cells. By using the acoustic sensor based on slot-mode a criterion of E. coli sensitivity to ampicillin was established. The advantages of this method are the ability to carry out the analysis directly in the liquid, the short analysis time (within 10–15 min), and the possibility to reusable sensor.

An acoustic delay line consisting of two Y – X -cut lithium niobate plates 0.2 mm thick placed on top of each other was experimentally investigated. An interdigital transducer is located at the edge of each plate. An rf voltage (pulsed or continuous-wave) is fed to one transducer, which excites a piezoelectrically active acoustic wave with transverse–horizontal polarization propagating in the first plate. The electric field of this wave penetrates the second plate to excite an acoustic wave therein, which is converted into an electrical signal using the second interdigital transducer. The phase and delay time of the output signal can be changed by varying the distance between the transducers by shifting one plate relative to the other.

The recent compute-in-memory (CiM) architectures are proposed as a promising solution to support Deep Neural Network and Convolutional Neural Network to solve large and complex tasks in various machine learning applications. The CiM architecture overcomes the limitation of the current Von-Neumann architecture by performing logic computations within the memory also called as in-memory computing. In most CiM, the in-memory logic operations are performed on the weights stored in memory using the inputs that are processed through bitlines or wordlines using pulse width modulated (PWM) signals. For precise operation, the applied input signals must be stable. However, one of the main challenges faced during the input signal generation is the deviation in the width values due to process, voltage, and temperature variations. Addressing this challenge, in this work, we aim to mitigate the impact of one of these variations on the generated PWM signals. Therefore, in this work, we propose to design a tunable delay line that provides a linear PWM signal corresponding to an input vector which is further utilized to perform local computation in memory. Further, to minimize the impact of process variations, we propose an autonomous on-chip calibration circuit that dynamically tunes the delay lines to obtain stable and process-invariant pulse width modulated signals. Our simulation results for the proposed DL demonstrate a total delay of 559 psec with a delay error of less than 2% under various process corners.

This article presents the design method of a compact MEMS switched-line true-time delay line (TTDL) network over a wide frequency range extending from 2 to 42 GHz using TTDL units. The TTDL units, namely the cascading radio frequency micro-electromechanical system (RF MEMS) switches and GCPW, were employed in the proposed TTDL network to improve the delay-bandwidth product (DBW) while maintaining its compact size and low delay variation (DV). For comparison, a theoretical analysis of the RF MEMS switch was performed while observing the switch performance with various top electrodes. The MEMS TTDL network has a compact size of 5 mm × 5 mm, with a maximum delay of 200 ps and a minimum of 30 ps. The maximum insertion loss of 9 states is 10 dB, and the in/out return loss is better than 20 dB across 2-42 GHz. The group delay variations are within ±2.5% for all the delay states over the operating frequency range. To the best of our knowledge, the proposed TTDL network obtains the most control bits among the TTDL networks offered to date.

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.

In the field of modern optical communication, radar signal processing and optical sensors, true time delay technology, as a key means of signal processing, can achieve the accurate control of the time delay of optical signals. This study presents a novel design that integrates a 2 × 2 Multi-Mode Interference (MMI) structure with a Mach–Zehnder modulator on a silicon nitride–lithium niobate (SiN-LiNbO3) heterogeneous integrated optical platform. This configuration enables the selective interruption of optical wave paths. The upper path passes through an ultralow-loss Archimedes’ spiral waveguide delay line made of silicon nitride, where the five spiral structures provide delays of 10 ps, 20 ps, 40 ps, 80 ps, and 160 ps, respectively. In contrast, the lower path is straight through, without introducing an additional delay. By applying an electrical voltage, the state of the SiN-LiNbO3 switch can be altered, facilitating the switching and reconfiguration of optical paths and ultimately enabling the combination of various delay values. Simulation results demonstrate that the proposed optical true delay line achieves a discrete, adjustable delay ranging from 10 ps to 310 ps with a step size of 10 ps. The delay loss is less than 0.013 dB/ps, the response speed reaches the order of ns, and the 3 dB-EO bandwidth is broader than 67 GHz. In comparison to other optical switches optical true delay lines in terms of the parameters of delay range, minimum adjustable delay, and delay loss, the proposed optical waveguide digital adjustable true delay line, which is based on an optical switch and an Archimedes’ spiral structure, has outstanding advantages in response speed and delay loss.

This paper describes an efficient method of designing and implementing in FPGA devices complex tapped delay lines (CTDL) with pico and sub-picosecond resolution. Achieving a higher resolution and better linearity is possible by appropriate selection of single time coding tapped delay lines (TDL) involved in creation of CDTL. The proposed TDL selection algorithm significantly optimizes the size of the device’s logical resources required to implement CDTL with assumed parameters and provides a proper selection scenario. Ultimately, the presented solution allows to create CTDLs with different user-defined configurations based on a fixed set of available logical resources. Therefore, it is particularly recommended for prototyping in smaller FPGA devices. In this work, we investigate how the order of line selection influences the increase of the multiple time coding lines resolution. Furthermore, we determine the relation between the equivalent resolution value and the number of TDLs involved. Obtained results allow to estimate the upper limit of resolution that can be achieved using a given technology. In addition, the ranges of resolutions achievable with a fixed number of lines is also examined. The presented research results have been performed on a Kintex UltraScale FPGA chip, manufactured by Xilinx in the 20-nm CMOS process.

Terahertz time-domain spectroscopy (THz TDS) is a well-known tool for material analysis in the terahertz frequency band. One crucial system component in every time-domain spectrometer is the delay line which is necessary to accomplish the sampling of the electric field over time. Despite the fact that most of the uncertainty sources in TDS have been discussed, the delay line uncertainty has not been considered in detail. We model the impact of delay line uncertainty on the acquired THz TDS data. Interferometric measurements of the delay line precision and THz time-domain data are used to validate the theoretical model.

The main advantage of phase noise meters with photonic (fiber) delay lines is that they do not require high-performance, low-noise reference oscillators. On the other hand, some additional calibrations are required, which are the subject of this paper. First, the quadrature must be maintained on the mixer by precise adjustment of the phase and/or delay. Next, since the response of the mixer is proportional to the square of the input test signal, a precise amplitude calibration is required. Finally, the frequency response of the FFT spectrum analyzer and its corresponding anti-aliasing low-pass filter needs to be known precisely. In this paper, to the best of our knowledge, we present innovative solutions for all three calibrations. All three calibrations were built in and tested in our phase noise meter. The result is a simple and robust phase noise meter suitable for non-laboratory environments.

We present two main ways to precisely create the equivalent transfer function of picosecond time-to-digital converters based on commonly used method with tapped time coding delay lines. The ways consist either in evaluation of the quantization steps boundaries of the delay lines or in summation of numbers of the line quantization steps. The paper contains results of comprehensive analysis of both methods. The advantage and high versatility of the addition method is demonstrated.