Pulse Width Of Signal Research Articles

DSC-based Generation of Sinusoidal PWM Signals with the Least Number of Variables for Single-, Two- and Three-phase inverters(Dept.E)

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Baseband Model for Uniformly Sampled RF-PWM

A baseband model for a polar RF modulator based on uniform sampling (US) pulse width modulation (PWM) is presented. RF-PWM allows to encode a complex baseband signal (amplitude and phase) into the pulse width and pulse position of a binary signal towards an efficient and fully digital RF transmitter implementation. We extend the well-known derivation of the naturally sampled (NS) RF-PWM to obtain a detailed model of the US RF-PWM which includes the intrinsic inband and side-bands distortion. In RF-PWM the carrier frequency is equal to the PWM frequency (first PWM harmonic). We develop the model such that the first or any other higher harmonic of the PWM can be used as the carrier signal. The distortion signal is analyzed in detail and a discrete-time implementation of the model which relates to previous approaches is presented. This model is key to the analysis, characterization and simulation of a fully digital transmitter.

On the DC Offset Current Generated during Biphasic Stimulation: Experimental Study

This paper deals with the DC offset currents generated by a platinum electrode matrix during biphasic stimulation. A fully automated test bench evaluates the nanoampere range DC offset currents in a realistic and comprehensive scenario by using platinum electrodes in a saline solution as a load for the stimulator. Measurements are performed on different stimulation patterns for single or dual hexagonal stimulation sites operating simultaneously and alternately. The effectiveness of the return electrode presence in reducing the DC offset current is considered. Experimental results show how for a defined nominal injected charge, the generated DC offset currents differ depending on the stimulation patterns, frequency, current amplitude, and pulse width of a biphasic signal.

A pulse controllable voltage source based on triboelectric nanogenerator

Abstract The large matching impedance and low-current output characteristics of the triboelectric nanogenerator (TENG) make the effective output of TENG severely limited for directly powering electronic devices. Here, we proposed a novel pulse controllable voltage source based on TENG (PCVS-TENG) by combining a TENG with a series of electronic components (a rectifier bridge, a capacitor) and an unidirectional switch, which can exceed the impedance matching limit of conventional TENG, and realize controllable voltage output regardless the load resistance. Based on the results, when the open-circuit voltage (Voc) and short-circuit current (Isc) of TENG can arrive at 495 V and 6.49 μA, but for PCVS-TENG (with a 1 nF capacitor), the Voc and Isc can reach 120 V and 87 μA, respectively. Corresponding output power at low load resistance (1 MΩ) of PCVS-TENG can achieve 7.569 mW, which is 145.5 times than the maximum output power (52 μW) of TENG with a load of 1 MΩ. It is noteworthy that the pulse width of the output signal can be controllable by controlling the capacitance, and the wonderful reliability and excellent Isc stability at different working frequencies of PCVS-TENG can be observed. Furthermore, by adjusting the capacitance in PCVS-TENG, various output signal waveforms can be generated, such as square wave, sawtooth wave and so on. The energy generated by PCVS-TENG can be directly used for the separate organic dyes from methyl orange solution (MO) as chemical raw materials through a self-powered electrocatalytic system.

Extraction of the pulse width and pulse repetition period of linear FM radar signal using time-frequency analysis

A common technique used by military to realize low probability of intercept (LPI) is linear frequency modulation (LFM) in the field of electronic intelligence (ELINT). This paper estimates the pulse width (PW) and the pulse repetition period (PRP) of LFM signal using instantaneous powers. The instantaneous powers were obtained either using time-marginal or power maxima approximated from a modified version of the Wigner-Ville distribution (WVD). The instantaneous power was also gotten directly from the signal by multiplication with its conjugate. Measurement was then carried out when the instantaneous power is ‘ON’ (the PW) and when it is ‘OFF’ (the PRP) at carefully selected thresholds. Thereafter, the mWVD-based algorithm was tested in the presence of additive white Gaussian noise (AWGN) at various signal-to-noise ratios. Results obtained during the test showed that the time marginal method emerged the best with minimum signal-to-noise ratio (SNR) of -5dB followed closely by the direct method with minimum SNR of -1dB at different thresholds. The results show that the proposed algorithm based on this modified WVD can be deployed in the practical field to determine radar’s performance and function

Enhancement of Range Resolution using Two Receivers in Continuous Time Frequency Modulation Technique

The resolution in range in continuous time frequency modulation (CTFM) is directly proportional to the pulse width of the compressed signal. The two receiver technique for continuous transmission frequency modulation processing was proposed as a technique to make resolution independent of the pulse width. In two receiver technique the output is without any discontinuity in time. Practically, it has been observed that the resolution in range is also limited by the pulse width of the probe signal bandwidth in the two receiver CTFM technique. The actual performance and limitation of the two receiver technique has been given in this paper.

An AMOLED Pixel Circuit Based on LTPS Thin-film Transistors with Mono-Type Scanning Driving

Using low-temperature poly-silicon thin-film transistors (LTPS TFTs) as a basis, a pixel circuit for an active matrix organic light-emitting diode (AMOLED) with narrow bezel displays was developed. The pixel circuit features mono-type scanning signals, elimination of static power lines, and pixel-integrated emitting control functions. Therefore, gate driver circuits of the display bezel can be simplified efficiently. In addition, the pixel circuit has a high-resolution design due to an increase of the pulse width of the scan signal to extend the threshold voltage and internal–resistance drop (IR drop) detection period. Further, regarding the influences of process–voltage–temperature (PVT) variation in the pixel circuit, comparison investigations were carried out with the proposed circuit and other pixel circuits with mono-type scanning signals using Monte Carlo analysis. The feasibility of the proposed pixel circuit is well demonstrated, as the current variations can be reduced to 2.1% for the supplied power reduced from 5 V to 3 V due to IR drop, and the current variation is as low as 10.6% with operating temperatures from –40 degrees to 85 degrees.

Needle-Size Bending Actuators Based on Controlled Nitinol Curvatures and Elastic Structures

Abstract Surgical navigation of small lumens during surgery is a challenging task, requiring expert knowledge and dexterity. The challenge pertains to the manipulation of the distal tip (inside the patient) from the proximal end (outside the patient). Limitations in down-scaling tendon-based manipulation have led our group to investigate shape-memory-alloy, curvature-based actuation for small lumen navigation. We demonstrate two prototype designs with different approaches and characterize the deflection angles for use in surgical navigation. Nitinol wire was shape trained to memorize a particular curvature and assembled without using micro-fabrication techniques. By varying actuation voltage and control signal pulse width, we show controlled deflections ranging between 5 deg and 22 deg, which applies to surgical navigation. This concept improves distal control and makes the actuation of surgical actuators easier and safer. By varying voltage between 5.7 V to 6.3 V, we show the temperature generated ranging between 37 °C and 43 °C, the force generated ranging between 0.015 N and 0.021 N experimentally and 0.01 N and 0.028 N theoretically.

Estimation of time-parameters of Barker binary phase coded radar signal using instantaneous power based methods

This paper deals with analysis of the Barker binary phase radar signal as part of ways to counteract upcoming threats in the field of electronic warfare support (ES) system. The ES part of electronic warfare (EW) provides tactical support by providing key information to other sections responsible for providing response in the form of attack and protection. The analysis of this paper focused on the correct estimation of the basic time parameters (pulse width and pulse repetition period) of this radar signal using instantaneous power obtained from the time-marginal of the time-frequency distribution (TFD), the maxima (power) of the TFD and directly from the product of signal. The main TFD is a modified version of the most common quadratic TFD (QTFD), the Wigner-Ville distribution (WVD) using appropriately chosen separable kernels. This analysis and estimation method developed is tested in the presence of white noise of Gaussian probability density function at different signal-to-noise ratios (SNR). Results obtained show that instantaneous power gotten from the maxima of TFD outshines the other methods with a minimum SNR of?14 dB when the specific threshold of 37.5% is used. It also shows that the proposed methods chosen outperform previous works of similar objectives and therefore, making it suitable for practical EW systems.

Three-dimensional FTn finite volume solution of short-pulse laser propagation through heterogeneous medium

In this paper, 3-D heterogeneous medium, containing small inhomogeneous zones, subjected to a short-pulse laser has been examined by solving the transient radiative transfer equation. Both curved-line advection method and STEP schemes of the FTn finite volume method have been applied. The curved-line advection method predictions proved that a decrease of the false scattering and ray effects are obtained. In fact, there was a good agreement between the curved-line advection method and the Monte Carlo method. However, the STEP results are slightly mismatching the predictions of the aforementioned reference method. Then, the effects of the absorption coefficient, the size, the number and the position of inhomogeneous zone on the transmittance and reflectance signals have been analyzed. The predictions showed that the increase of the size of the inhomogeneity reduces the intensity of radiation. For both homogenous and heterogonous medium, the change of the detector position varies both the broadening of the signal pulse-width and the time with peak reflectance and/or transmittance. That is can be explained by the effects of the distance and the medium property between the laser-incident source and the detector position. Thus, these both parameters are the main factors for determining the peak position and the pulse broadening. Finally, the effects of the absorption coefficient in the inhomogeneity zone on the absolute values of logarithmic slope has been discussed. The results proved that the absolute values of logarithmic slope may be a perfect indicator for detecting any abnormal absorbing zones in the medium.

Komunikasi Suara Sinyal Digital Dengan Transmisi Frekuensi 2,4 Ghz

The limitations of developing high-tech communication systems cause the area of people who can use this service to be uneven. One technology that can be used for areas not yet reached by this high-tech communication service is to use radio communication technology. Today radio communication technology continues to develop and produce an increasingly limited frequency spectrum. One way to improve the efficient use of available frequency spectrums is the transition from analog technology to digital technology. A very significant benefit in the use of digital technology is to save the use of radio frequency spectrum bandwidth with signal compression techniques. One device that still uses analog technology is a handy talky (HT). In addition to the lack of frequency spectrum efficiency, HT technology still requires a radio station license (ISR) for its use. This experiment designed a two-way digital audio communication system that was transmitted using the NRF24L01 radio frequency transceiver module on the 2.4Ghz frequency. Analog input data from the microphone will be converted into digital data through the ADC (Analog to Digital Converter) process using a microcontroller and the digital data that will be sent is first digitally modulated using GFSK modulation then transmitted digitally. On the other hand data that already contains voice information received again by another NRF24L01 transceiver is received by the Arduino microcontroller and then formed into a PWM signal (pulse width modulation) and then released to the speaker. So the method of using digital transmission can produce efficiencies in the frequency spectrum.

Particle Self-Aligning, Focusing, and Electric Impedance Microcytometer Device for Label-Free Single Cell Morphology Discrimination and Yeast Budding Analysis.

Microfluidic electric impedance flow cytometry (IFC) devices have been applied in single cell analysis, such as cell counting, volume discrimination, cell viability, etc. A cell's shape provides specific information about cellular physiological and pathological conditions, especially in microorganisms such as yeast. In this study, the particle orientation focusing was theoretically analyzed and realized by hydrodynamics. The pulse width (passing time for the particles) of the conductance signal was used to discriminate particle shapes. Spherical and rod-shaped particles with similar volumes/lengths were differentiated by the IFC device, using the impedance pulse parameters of the events. Then, typical late-budding, early budding, and unbudded yeast cells were distinguished by the width, amplitude, and ratio of width to amplitude (R) of the impedance pulse. The pulse amplitude and the R combination gate for identifying the late-budding yeast was estimated through the statistic results. Using the gate, the late-budding rates under different conditions were calculated. Late-budding rates obtained using our method showed a high correlation (R2 = 0.83) with the manual cell counting result and represented the budding status of yeast cells under different conditions proficiently. Thus, the late-budding rate calculated using the above method can be used as a qualitative parameter to assess the reproductive performance of yeast and whether a yeast culturing environment is optimal. This IFC device and cell shape discrimination method is very simple and could be applied in the fermentation industry and other microorganisms' discrimination as a rapid analysis technique in the future.

High-accuracy tracking of piezoelectric positioning stage by using iterative learning controller plus PI control

Piezoelectric positioning stages as control system actuator are widely used in equipment drive. In this paper, according to the physical mechanism of the piezoelectric positioning stage control system, an approximate time-domain mathematical model is established for the selection of piezoelectric positioning stage control system. The least-squares method is used to identify the parameters of the model. The outputs of the pulse width signal of the obtained model are consistent with that of the actual system. Then, iterative learning controller plus proportional integral control based on frequency domain tools is designed according to the form of the model, the stability of the control approach and the selection of its parameters are discussed in detail. The experimental results demonstrate the successful implementation with good performance on the piezoelectric positioning stage.

Experimental study on a solenoid valve-based generator for droplet generation

An on-demand droplet generator is developed based on a high-speed and 2-way solenoid valve and studied experimentally in this paper. It is found that the valve-based droplet generator has good controllability, repeatability and stability. Under a suitable applied pressure, a single droplet can be generated by opening the valve with a short voltage pulse. Besides, the droplet size can be conveniently controlled by the applied liquid pressure and pulse width of the control signal. The results show that the present device successes to avoid the limitation of an appropriate outlet pressure required at nozzle tip for most droplet generators in the literature and is capable of producing droplets in a wide size range for a fixed nozzle diameter.

Application of a Novel Measurement Setup for Characterization of Graphene Microelectrodes and a Comparative Study of Variables Influencing Charge Injection Limits of Implantable Microelectrodes.

Depending on their use, electrodes must have a certain size and design so as not to compromise their electrical characteristics. It is fundamental to be aware of all dependences on external factors that vary the electrochemical characteristics of the electrodes. When using implantable electrodes, the maximum charge injection capacity (CIC) is the total amount of charge that can be injected into the tissue in a reversible way. It is fundamental to know the relations between the characteristics of the microelectrode itself and its maximum CIC in order to develop microelectrodes that will be used in biomedical applications. CIC is a very complex measure that depends on many factors: material, size (geometric and effectiveness area), and shape of the implantable microelectrode and long-term behavior, composition, and temperature of the electrolyte. In this paper, our previously proposed measurement setup and automated calculation method are used to characterize a graphene microelectrode and to measure the behavior of a set of microelectrodes that have been developed in the Fraunhofer Institute for Biomedical Engineering (IBMT) labs. We provide an electrochemical evaluation of CIC for these microelectrodes by examining the role of the following variables: pulse width of the stimulation signal, electrode geometry and size, roughness factor, solution, and long-term behavior. We hope the results presented in this paper will be useful for future studies and for the manufacture of advanced implantable microelectrodes.

Fully Digital Driving Circuit for TFT LCD Using the Concept of Ramp-Stop

A fully digital driving circuit for thin-film transistor liquid crystal display can offer benefits, including less power consumption and a shortened design schedule. Using the pulsewidth signal to control the moment to stop the ramp voltage, the pixel voltage can be set accurately. In this paper, the possible issues of power consumption, device nonuniformity, and parasitic capacitance are well-studied to prove the feasibility and advantages of the digital driving method. It is prospectively expected to substitute for the conventional analog driving method in the future.

Analysis of coupling effect of high-power microwave on millimeter wave fuze

Aiming at the front door coupling effect of high-power microwave on millimeter wave fuze, the electromagnetic simulation software was used to irradiate a certain millimeter wave FM continuous wave fuze model, and the joint simulation was carried out with the front-end limiting circuit of the fuze. On this basis, orthogonal experiments are designed to analyze the influence level of signal parameters. When the high-power microwave signal frequency is aligned with the fuze working frequency, the simulation results show that the maximum coupling voltage at the end of the antenna can reach 188 V when the peak radiation field intensity is 60 kV/m. When the peak radiation field intensity is 40 kV/m, changing the characteristic parameters of the radiation signal and finds that the long pulse width signal is more likely to cause the thermal breakdown effect of the limiter; the rising time of the signal will affect the end of the antenna. When the peak value and pulse width of the coupled voltage waveform are fixed, the spike leakage voltage caused by the input signal with rise time of 5 ns is about 5.94 V, while the spike leakage voltage is 18.4 V when rise time is 0.1 ns, and the limiting circuit reaches saturation state faster. The orthogonal experiment shows that the spike leakage peak voltage is most affected by the rise time of the signal, and the signal peak is the largest, meanwhile the value has the second effect on it.

The Design of New Compact Marx Generator

At present most of the Marx generator based on semiconductor switches not only need generate the same number of trigger signals as the number of switches, but also consider the isolation from output high voltage and driving the signal processing, which makes Marx generator have complex circuits, large volume. In this paper, a new type of Marx generator based on semiconductor switches is designed. This generator need only one trigger signal which is generated by an avalanche transistor, other switches are triggered by the signals which are generated by voltage dividing capacitive. In the PSPICE, a five-stage Marx generator is designed. Choosing a 400V DC voltage source charged, pulse voltage with 1.9KV amplitude and 100ns pulse width is obtained. Finally, a fourstage Marx generator is designed. The charging voltage is 200V and the pulse width of trigger signal is 500ns. A pulse voltage with amplitude 736V and pulse width 562ns is obtained.

All-optical differential equation solver with tunable constant-coefficient based on inverse Raman scattering effect in a silicon microring resonator

The all-optical differential equation solver has great potential in high-speed and wide-band signal processing, such as special waveform generation and description of the complex dynamics. We propose an all-optical differential equation solver in a silicon microring resonator with tunable constant coefficient k. Using inverse Raman scattering effect, k can be tunable by changing the power of the incident pump light. The influences of the pump power and signal pulse width on the tunable range of k are investigated. It is demonstrated that k is continuously tunable in the range of 0.035 / ps to 0.130 / ps with the error of <5 % .

Threshold decrease in intracavity optical parametric oscillator synchronously pumped by mode-locked laser

An intracavity optical parametric oscillator (IOPO) pumped by a continuous-wave (CW) mode-locked laser is experimentally realized. The fundamental cavity and optical parametric oscillator cavity are designed to satisfy synchronous pumping. The output characteristics of signal and idle light are measured. Because of higher fundamental photon intensity in IOPO, the threshold of IOPO is lower than that of an extra-cavity optical parametric oscillator. The spectroscopy of signal light is obtained and the wavelength of idle light can be estimated to be 3.298 μm from noncritical phase matching. Based on the intensity fluctuation mechanism of fundamental locking, the dynamical model for IOPO pumped by a CW mode-locked laser is developed. The simulated results for the temporal shape of three lights are calculated from the derived rate equations. Because of dispersion, the signal pulse width of the theory is smaller than that of the experiment with the same pump energy.