Output Pulse Amplitude Research Articles

Investigation of the Influence of Infrared Illumination on the Pulse Shapes of Output Signals of CdZnTe Detectors.

The spectrometric characteristics of CdZnTe detectors are largely determined by the nonuniformity of the material and the influence of the negative polarization effects associated with the formation of space charges in the sensitive volume of the detector. They change the electric field distribution in the detector and affect the efficiency of the charge carrier collection. An analysis of the waveforms of the output pulses was used to investigate the uniformity of the charge collection and electric field distribution in the detectors when irradiated by the alpha particles. The influence of infrared (IR) illumination on these parameters was evaluated. IR illumination had no positive effect on the planar detector but greatly improved the charge collection in quasi-hemispherical detectors in the peripheral (corner) regions. The output pulse amplitude increased, and the rise time notably decreased. Polarization that occurred predominantly in the corner regions at low temperatures (from -30 °C to -20 °C) was eliminated using IR illumination.

Study of Bipolar Inductively Isolated High-Voltage Pulse Source

To meet the application requirements of pulsed power technology in wastewater treatment and other aspects (for example, a scenario that requires a high-voltage pulse source that can output a pulse with a rising edge in the nanosecond range and a device that can stabilize the pulse under high-frequency conditions), this paper designed an inductively isolated bipolar high-voltage pulse source. It consists of three parts: the primary charging power supply, the isolated driver circuit, and the pulse-forming circuit. By using inductance instead of traditional resistance isolation, using the inductance for charging and isolation, the inductance can increase the charging voltage of the capacitor, so the circuit can achieve a higher voltage output. The dual-Marx generator parallel connection design of the pulsed power supply topology, using a primary charging power supply for positive and negative polarity charging, can simultaneously output the reverse polarity and size of high-voltage pulses to achieve a bipolar output, so the load has an effect on the pulse. The equipment was selected on the basis of the design of the isolated driver circuit, primary charging power supply circuit, and pulse-forming circuit for the corresponding simulation, and in the experiment to build a principle model, the tests showed that the pulse source output pulse amplitude range was 0~10 kV (the positive pulse voltage was 5 kV, and the negative pulse voltage was −5 kV), the pulse rising edge was approximately 200 ns, the pulse width was 1 μs, and the frequency range was 0~1 kHz for the pulse source frequency. The power supply was designed to be used in applications such as wastewater treatment.

Design and manufacture of scintillation detector using CsI(Tl) crystal coupled with silicon photomultipliers

In this research, a scintillation detector was developed using the CsI(Tl) scintillator crystal coupled with a silicon photomultiplier (SiPM) to replace the photomultiplier tube (PMT), resulting in a compact and energy-efficient detector. A rectangular box-shaped CsI(Tl) scintillation crystal with dimensions of 50x25x25 mm from Kinheng and a SiPM module S13361-3050AE-08 with dimensions of 25x25 mm from Hamamatsu were selected to use. The preamplifier circuit, power supply, and temperature stabiliser have also been integrated into the detector. The characteristics of this detector were evaluated using a 137Cs standard radioactive source together with Ortec’s multichannel analyser device and Gamma Vision software for spectrum analysis. Results showed that the energy resolution for the 137Cs peak of this detector is about 8.03%, which is almost equivalent to the energy resolution of 7.87% of the Canberra detector using 76x76 mm NaI(Tl) crystal coupled to the PMT. The results of the evaluation of stability over time when the operating ambient temperature of this detector with no change showed that the energy peak position and the energy resolution for the 137Cs radioactive source are almost unchanged. The research also investigated the stability of the detector according to the operating ambient temperature. The results exhibited that the output pulse amplitude varies greatly with the ambient temperature, it decreases when the temperature increases and vice versa. Under the condition that the operating ambient temperature varies from 11oC to 50oC, the energy peak position of 137Cs changes were 1762 and 167 channels, respectively in the cases without and with adjustment of output pulse amplitude stabilisation function in power supply for SiPM. When there is a function of output pulse amplitude stabilisation, the change in peak position according to operating ambient temperature is still about 4.3 channels/oC, so further research is needed to correct the influence of ambient temperature on the operation of this detector, to provide wide applicability of scintillation detector using SiPM to replace traditional PMT in the future.

Side-Illuminated Photoconductive Semiconductor Switch Based on High Purity Semi-Insulating 4H-SiC

High purity semi-insulating (HPSI) 4H-silicon carbide (SiC) was used to fabricate lateral and vertical photoconductive semiconductor switches (PCSSs). The lateral PCSSs were illuminated from the frontside (fPCSS) or the backside (bPCSS). The side-illuminated vertical PCSS (vPCSS) was designed to increase the light-matter interaction volume. A 532-nm pulsed laser with adjustable energy was utilized to excite the PCSSs. The turn-on time was found to be highly dependent on the optical illumination energy, and the full-width at half-maximum of the PCSSs output waveforms was related to the peak output voltage. The output electrical pulse from the vPCSS exhibited a shorter turn-on time and a larger pulsewidth than the two types of lateral PCSSs. The vPCSS outperformed the fPCSS and bPCSS in terms of minimum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{\scriptscriptstyle ON}$ </tex-math></inline-formula> -state resistance and output pulse amplitude under the same optical illumination energy. The vPCSS, which utilizes a large effective contact area to collect photogenerated carriers, also had higher photon absorption efficiency by arranging the optical path at a right angle to the carrier transport. The vPCSS exhibited a minimum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{\scriptscriptstyle ON}$ </tex-math></inline-formula> -state resistance of 0.34 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> at optical illumination energy of 8 mJ.

Design and Implementation of a Capacitive Energy Storage Pulse Drive Source

According to the requirement of driving power supply for pulsed semiconductor laser, a method of constant current output is proposed by combining large energy storage capacitance with MOS transistor working in linear region to solve the problem of generating high amplitude, short pulse width and high stability current pulse on low impedance load. The front stage uses the buck circuit to charge the energy storage capacitor, and through the hysteresis control of the buck circuit, the voltage of the energy storage capacitor is controlled. In the latter stage, the MOS transistor working in the linear region is used to realize the pulse output, and the PI module is used to adjust the output current to ensure the constant output current. Through PSPICE simulation, the key factors affecting the output pulse amplitude, pulse width and rise time are analyzed and verified by experiments. Using 155V DC power supply, the experimental results show that the capacitor energy storage pulse driver circuit can achieve a pulse constant current output with amplitude of 30A, pulse width of 300μs and rise time of less than 10μs on a 5 Ω low impedance load.

A differential IR-UWB transmitter using PAM modulation with adaptive PSD

The current state of the telecommunications market exhibits a high potential to absorb efficient innovations in wireless connectivity, especially those that can be applied to the Internet of Things and similar domains. Contributing in that direction, this paper describes the design and implementation of a fully differential impulse-radio ultra-wideband (IR-UWB) transmitter using pulse-amplitude modulation, with an adaptive power spectrum density (PSD). The architecture can produce up to eight differential monocycles per clock pulse at its output. The number of monocycles controls the bandwidth (thus the PSD) in the mask of IR-UWB technologies, allowing adaptation to multiple standards. The complete transmitter has four main blocks: (a) a pulse generator, comprising two pulse generating circuit groups, to modulate and create a rectangular waveform; (b) an active balun with two amplifiers, to generate differential signals; (c) a digital demultiplexer, to alternate data to the pulse generating circuit groups; (d) a binary-to-thermometer decoder, to control the amount of generated monocycles per pulse. Simulations demonstrate an output pulse amplitude of 120 mV for the high logic level and of 70 mV for the low logic level, both at a 100 MHz Pulse Repetition Frequency. This produces a mean pulse duration of 277 ps, a mean central frequency of 3.8 GHz, and a mean power consumption 6.7 mW. The transmitter takes the form of an intellectual property core in a 130 nm CMOS technology. The complete transmitter area is 0.067 mm $$^2$$ , without I/O pads. The outcomes suggest that the proposed circuit can narrow or widen the output signal bandwidth, providing adaptability to different emission requirements.

Design and Implementation of High Power Pulse Constant Current Source

According to the requirement of the semiconductor laser for driving power supply, aiming at the problem of how to produce the current pulse with high amplitude, short pulse width and high stability on the low impedance load, a method of realizing the constant current output of the pulse by using the combination of the buck transform circuit and the linear regulation module is proposed. The Buck circuit is hysteresis controlled to control the storage capacitance voltage, and then the MOSFET working in the linear region is adjusted by the PI module to ensure constant current output on the load. The key factors affecting the output pulse amplitude, pulse width, front and back edge parameters are also analyzed and verified by experiments. The results of 170V DC power supply show that the circuit designed in this paper can output 30A, 250us pulse width and rise time less than 10us pulse constant current output on 5Ω low impedance load.

Area- and Energy-Efficient Sub-GHz Impulse Radio UWB Transmitter With Output Amplitude Enhancement for Biomedical Implants

This brief presents an almost fully digital edge-combining impulse radio ultra-wideband (UWB) transmitter. The proposed output amplitude enhancement technique increases the peak-to-peak amplitude of the UWB output pulse to more than two times that of the traditional UWB transmitter. The pulse width adjustment circuit is designed to ensure the robustness of the UWB circuit against process, supply voltage, and temperature variations. The output power spectrum density of this transmitter is primarily concentrated in the range of 0-960 MHz and can satisfy the mask requirement of the Federal Communication Commission for UWB communication. The proposed UWB transmitter is implemented in a 0.18- μm CMOS process and occupies an area of 97.41 × 68.6 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measurement results of 20 samples indicate that the average output amplitude is 106.02 mV at a supply voltage of 1 V. At the data transmission rate of 50 Mbps, the measured energy consumptions are 11.18 and 3.97 pJ/bit, respectively, at the supply voltages of 1 and 0.8 V.

An Efficient Ultrawideband Pulse Transmitter With Automatic On–Off Functionality for Primary Radar Systems

This letter proposes an ultrawideband (UWB) transmitter for a UWB primary impulse radar that is designed for real-time pedestrian localization. The proposed transmitter applies a novel combination of a UWB pulse generator followed by a UWB amplifier to boost output pulse amplitude, which is able to be turned off automatically after one pulse transmission in order to reduce power consumption. The transmitter has been fabricated using 45-nm SOI CMOS technology and has been measured on a printed circuit board (PCB). The produced pulses possess a high measured peak-to-peak amplitude of 425 mV and a width of around 600 ps. The power spectral density (PSD) of the pulse achieves a maximum of −41 dBm/MHz at 6 GHz with a −10-dB bandwidth of 4.5 GHz from 3.3 to 7.8 GHz that assures that the proposed transmitter complies with the regulation of the U.S. Federal Communications Commission (FCC) for UWB outdoor applications. The pulse generator consumes around 10 pJ/pulse from a 1-V supply, which is very low among the similar designs, and remains almost constant with an increasing pulse repetition time (PRT).

Estimating the Precision of a Leading-Edge Discriminator with Amplitude Correction

Abstract—The formation of time stamps that are independent of the sensor output pulse amplitude in the domain of event timing is well-known problem. It is shown that the time-stamp accuracy (time walk) can be estimated using high-speed arbitrary-signal generators and general-purpose time meters with an uncertainty of the estimate of no worse than 0.2 ps. The efficiency of the technique is demonstrated for a leading-edge discriminator (LED). The proposed LED version combined with an amplitude meter and amplitude correction has a 17-ps time walk.

Photoresponses of the back-side illuminated GaAs photoconductive semiconductor switches in the linear mode

Photoresponses of the back-side illuminated photoconductive semiconductor switches (PCSSs) in the linear mode are studied. It has been found that the back-side-illuminated PCSS enjoys the better performance than that of the front-side-illuminated one. Photogeneration of electron-hole pairs beneath the contacts under the back-side illumination condition significantly reduces the resistance of the PCSS leading to the higher output pulse amplitude up to 4.6 times. Impact of the beam center position on the output waveform is also investigated for both the illumination cases. The laser beam centered near the cathode yields the slowly-decaying output pulse waveform. On the other hand, the rapidly-decaying waveform is observed with the beam centered near the anode.

Numerical and Experimental Study of an Optimized p-SOS Diode

We report on the results of experimental investigation and numerical simulation of switching of SOS diode with p+P0n+ structure and with reduced thickness of P0-base. The proposed 1D diffusion-drift model of electron–hole plasma dynamics is found to be in good agreement with the experiment. The reduction of the P0-base thickness has allowed us to double the output pulse voltage with the same switching current density. This has been reached by a considerable reduction of switching losses as well as due to the formation of the domain of a strong quasi-rectangular electric field at the P0n+ junction during the current interruption. As a result, output pulse amplitude considerably exceeds the static breakdown voltage of P0n+ junction. This effect has been observed for the first time for high-voltage semiconductor opening switches.

Численное и экспериментальное исследования оптимизированного p-SOS-диода

AbstractWe report on the results of experimental investigation and numerical simulation of switching of SOS diode with p ^+ P _0 n ^+ structure and with reduced thickness of P _0-base. The proposed 1D diffusion-drift model of electron–hole plasma dynamics is found to be in good agreement with the experiment. The reduction of the P _0-base thickness has allowed us to double the output pulse voltage with the same switching current density. This has been reached by a considerable reduction of switching losses as well as due to the formation of the domain of a strong quasi-rectangular electric field at the P _0 n ^+ junction during the current interruption. As a result, output pulse amplitude considerably exceeds the static breakdown voltage of P _0 n ^+ junction. This effect has been observed for the first time for high-voltage semiconductor opening switches.

Design and Development of a Compact All-Solid-State High-Frequency Picosecond-Pulse Generator

The Marx circuit structure based on fast high-power semiconductor devices is the classical way of generating picosecond pulses. However, most reported studies suggest that as the number of stages in the Marx circuit increases, the output pulse amplitude tends to saturate. This has of late made high-voltage picosecond-pulse generation a challenge. In this paper, as the number of stages increases, the internal resistance of the avalanche transistor tends to decrease with increasing current flowing through the avalanche transistor. A step-by-step wiring and debugging of the avalanche transistor-based Marx circuit demonstrates this experimentally. That is, for a certain range in the number of stages, saturation of the output pulse amplitude for the Marx circuit of avalanche transistors is not apparent. Introducing a parallel structure for the transistors not only increases the current level of the entire circuit but also further reduces the equivalent resistance of the avalanche transistors, thereby improving the output efficiency. Drawing on microstrip transmission theory, and combining the Marx circuit and avalanche transistor parallel structure, component parameters and circuit topology of the picosecond-pulse generator were redesigned, and a 30-level Marx circuit with a parallel structure of two avalanche transistors was developed. The picosecond-pulse generator outputs a pulse with adjustable voltage amplitude of 0.9–3.1 kV, a 350-ps full-width at half-maximum, a 150-ps rise time, and an adjustable high-stability repetition rate of up to 10 kHz. The number of pulses is precisely controlled. The generator is an all-solid-state compact device with high frequency suitable for research needs.

A CMOS Ultrawideband Pulse Generator for 3–5 GHz Applications

A low-power ultrawideband (UWB) pulse generator based on pulsed oscillator architecture for 3-5 GHz applications is proposed. The pulsed oscillator is improved, so it realizes binary phase shift keying (BPSK) modulation. Unlike ON-OFF keying or pulse-position modulation (PPM), BPSK can scramble the spectrum, so it can be used in high pulse rate applications without having spectral line problem. The signal structure in this design is burst mode of PPM+BPSK. The proposed UWB pulse generator was successfully implemented on 0.18-μm CMOS technology. The peak-to-peak amplitude of output pulse is about 220 mV with 50-Ω load, the maximum power consumption is 4 mW at a raw data rate of 7.8 Mbps and the energy consumption is 32 pJ/pulse at a pulse rate of 125 Mpulses/s.

Nanosecond time-resolved characterization of a pentacene-based room-temperature MASER

The performance of a room temperature, zero-field MASER operating at 1.45 GHz has been examined. Nanosecond laser pulses, which are essentially instantaneous on the timescale of the spin dynamics, allow the visible-to-microwave conversion efficiency and temporal response of the MASER to be measured as a function of excitation energy. It is observed that the timing and amplitude of the MASER output pulse are correlated with the laser excitation energy: at higher laser energy, the microwave pulses have larger amplitude and appear after shorter delay than those recorded at lower laser energy. Seeding experiments demonstrate that the output variation may be stabilized by an external source and establish the minimum seeding power required. The dynamics of the MASER emission may be modeled by a pair of first order, non-linear differential equations, derived from the Lotka-Volterra model (Predator-Prey), where by the microwave mode of the resonator is the predator and the spin polarization in the triplet state of pentacene is the prey. Simulations allowed the Einstein coefficient of stimulated emission, the spin-lattice relaxation and the number of triplets contributing to the MASER emission to be estimated. These are essential parameters for the rational improvement of a MASER based on a spin-polarized triplet molecule.

Simulated experiment research on SESD interference with integrated operational amplifier

Space electrostatic discharge (SESD) interference can result in soft errors to space-borne electronics and ultimately may lead to equipment or system anomalies or even whole-spacecraft failure. So far not much research work has been done on susceptibility of spacecraft equipment, especially typical electronic devices, to SESD interference. In this paper ESD generator is utilized to simulate SESD and investigate the response of LM124 OPAMP, a typical analog IC, to discharge interference. Results show that the output of LM124 may generate anomalous transient, the characteristics of which are related to device configurations, bias conditions and ESD voltage. Subjected to simulated SESD, voltage comparator only generates single polarity pulse. Voltage follower and non-inverter behave similarly. Inverter shows the least sensitivity. Sinusoidal waveform from a signal generator is injected to the input pins of LM124 to evaluate its EMI susceptibility. Analysis shows that the amplitude and duration of output pulse are strongly associated with input interference amplitude and frequency. This work has guiding significance to the intensive study of SESD effects on various typical devices, understanding the mechanism of spacecraft anomalies attributed to SESD and developing targeted protective measures.

Development of chip-less and wireless neural probe functioning stimulation and reading in a single device

A chip-less, wireless neural probe system was developed for stimulation of neurons and for reading of neural communications in the brain. The developed neural probe system is composed of a one-port surface acoustic wave (SAW) reflective delay line, neural firing-dependent ferroelectric capacitor, two antennas, and a network analyzer for reading of neural communications, as well as Schottky diode, static capacitor, and sharp metal tip for stimulation of neurons. The one-port SAW reflective delay line replaces existing wireless transceiver system composed of ~5000 electronic components and makes chip-less, wireless interrogation system possible. The probe for reading of neural signals employs PVDF ferroelectric capacitor which changes polarization and volume depending on neural firings. A 4.3nH inductor was also connected between one-port SAW reflective delay line and reading probe to obtain a large linearity and high sensitivity through impedance matching effect. As electrical pulses imitating neural signals were applied to the reading probe at a 0.9% saline solution, amplitude changes in the reflection peaks were observed depending on the magnitude of applied electrical pulses. Good linearity and sensitivity were observed at the amplitude variations in terms of electrical pulses. The probe system for stimulation of neurons consists of Schottky diode, capacitor, and sharp metal probe. By modulating RF input power and the number of cycle from interrogator, stimulation amplitude and duration time of the resultant output pulses are manipulated. Coupling-of-mode (COM) modeling was also performed to predict device performances and to find optimal device parameters.

D級アンプのEMIと歪みの低減に関する研究

Class D amplifier, which uses differential output signal between PWM pulses compensated difference of delay, which are obtained from input signal and from inversed input signal, is proposed. Proposed class D amplifier is shown to reduce amplitude of the differential output pulse to half. After the difference of delay was compensated, odd number harmonics noise from the differential output pulse was able to be reduced by more than 41 dB. Furthermore, harmonic distortion in the output signal was able to be reduced by more than 16 dB, and also its THD was reduced to 0.38 times and became to less than half of conventional circuit. The proposed circuit can be configured only by applying small modification to small-signal stage in integrated circuit. In addition to the reduction of EMI, there is an advantage in use of miniaturized components for LPF, because the output pulse frequency is able to be increased double of conventional in same sampling rate.

Simulation design of an compact mesoband high power microwave radiator

A high power wideband patch antenna array driven by two switched oscillators with synchronism output was designed, so as to increase the radiation factor of the mesoband high power microwave radiator. A single layer patch and an air substrate were employed to reduce the weight of the array, each patch is E-shaped for broadening the bandwidth. Optimization of the arrays geometric parameters was performed to get the highest radiation factor. As a result, the radiation factor is 3.4 times of the magnitude of the feed in mesoband pulse, the percentage of bandwidth is 47%, and the gain of the array is 11.8 dB at frequency of 300 MHz. Filling SF6 gas with a pressure of 1 atm in the nylon-case, the power capability of the array is as high as 7.45 GW. A novel mesoband pulse generator with the two-port synchronous output was provided. The generator has a dual-path sync output wideband resonator structure, in which two resonators share a shorting switch to achieve synchronous output. The design of the generator is optimized, and the coupler has a couple ratio of 0.644 at the frequency of 300 MHz. The simulation comparison between the generators with and without T-shaped charging structure was performed, which shows that the output pulse amplitude of the generator with the charging structure is only 4%, lower than that without the charging structure.