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Linac Coherent Light Source (LCLS) at SLAC is driven by eighty klystrons. Each klystron is powered by a modulator with up to 24 kV pulse at 120Hz repetitive rate. A pulse transformer in the klystron tank will transform the high voltage pulse to 350kV to drive the klystron. The modulator also includes a DC power supply as a core bias for the pulse transformer. The eighty core bias power supplies run...
Orthogonal Frequency Division Multiplexing (OFDM) is designed to improve the spectral efficiency and combat multipath fading by dividing the wide band frequency selective fading channel into many narrow flat sub-channels. The noise in the wireless communication channel may damage the OFDM transmission signal and reduce the signal-to-noise ratio (SNR) at the receiver, which limits the bit error rate...
The industrial development and Brazilian economic context led to important structural changes, among others, the increase of population migration (rural to urban spaces), number of private vehicles (due to tax reduction and state subsidies for new cars and fuel), among others. Such changes impact not only the urban mobility at big cities but also the urban life quality, which is directly affected...
A reduction in gate length Lg of FETs below 100 nm and corresponding improvements in transconductance gm, cutoff frequency ft and maximum frequency of oscillation fmax has not resulted in expected improvements in measured minimum noise temperatures Tmin (or noise figures Fmin). This observation applies to all FET technologies currently in use: FETs, HEMTs and MOSFETs. An explanation of this observation...
An injection-locked magnetron was investigated at low power injection. The 1 kW magnetron has been locked over the ratio of the input power to output power of −57 dB. It is much less than the required injection power in previous experiments. The purity of spectrum was presented. The phase noise of the locked magnetron was less than −93.1 dBc/Hz at 10 kHz offset. The oscillation spectrum has FM noise...
In this paper, after explaining the reasons why some players asked to standardize also the 3–150 kHz EMC maximum acceptable range, we describe the type of disturbances depending on the frequency range and on the type of equipment that can generate such disturbances. Furthermore, we illustrate the different methods to reduce them. In particular, we explain a method to design a suitable passive filter...
A new microstrip sensor using the transmission interferometric measurement principle for scanning near-field microwave microscopy is presented. The structure originates from a Wilkinson power divider but has a resistor removed. The wideband design was verified by simulation using AWR Microwave Office and experimentally in frequency band of 45 MHz to 20 GHz. Ten times suppression of measurement uncertainties...
The impact of DC current on excitation characteristic of transformer is analyzed under bipolar asymmetric operation of HVDC power transmission system. The operating performance of single-phase transformer with three-limb core located near DC grounding pole is measured, and the relationship of vibration, noise and oil temperature of the transformer with such parameters as unbalance degree of HVDC bipolar...
Schottky diodes are key elements of RF and terahertz electronics. The design of the lateral Schottky with the contact directly to the side of the electron 2D channel in GaN/AlGaN system provides an advantage of extremely small capacitance and series resistance. The lateral Schottky devices based on high quality GaN/AlGaN heterostructures were grown by molecular beam epitaxy. The current voltage characteristics...
The noise mechanisms in graphene and MoS2 are quite different. The noise characteristics of MoS2 transistors could be described by the McWhorter model. The range of the trap densities responsible for the 1/f noise in MoS2 extracted from the noise measurements is from ∼1018 eV−1cm−3 to ∼ 6×1020 eV−1cm−3. The smallest noise level and smallest trap density was found for multilayer MoS2 transistors with...
DC, RF and noise parameters of GaAs pHEMTs with 100 nm gate length and widths (μm) of 2×10, 2×15, 2×25, 2×50, 2×75, 4×50 were investigated with the focus on test structure with gate width of 2 × 50 µm. Using a Maury Microwaves ATS system in the 8–50 (K, Ka), 50–75 (V) and 75–110 GHz (W) frequency band, the noise parameters were measured and calculated employing the Y-Factor method. The sources of...
Resistivity and low frequency (10 Hz – 20 kHz) noise characteristics of composite materials with multi-walled carbon nanotubes (MWCNTs) have been carried out over wide voltage and temperature (73–380 K) ranges. Composite materials with epoxy-grafted (MWCNT's surface covered by liquid epoxy resin) and amino-grafted (MWCNT's surface covered by polyethylene polyamine) MWCNTs were investigated. Low-frequency...
Here we report on the efficient detection of THz radiation generated from Ti:sapphire femtosecond laser system. The large-area interdigitated antenna is excited by optical pulses with pulse duration from 15 to 47 fs. We have tested two AlGaN/GaN HEMT-based THz detectors with integrated broadband antennas. Detectors are comparable in sensitivity but differ in applied parasitic signals elimination techniques...
A novel comb-structure-based, capacitive MEMS microphone concept is proposed, which is expected to significantly reduce viscous damping losses, challenging the high performance of conventional MEMS microphones. To this end, we derived a dedicated, fully energy-coupled and properly calibrated system-level model scaling with all relevant design parameters. It enables to discriminate in detail the impact...
We report on ac-driven electroconvection (EC) in a nematic liquid crystal (NLC) under superposed multiplicative noise; the EC system consists of a thin layer (d = 10–100 µm) of an NLC in an applied electric field. Ac-driven traveling waves (TWs) have been one of attractive EC showing a Hopf bifurcation, which have been well explained by a weak-electrolyte model. In this paper, noise-induced traveling...
This paper reports a high performance capacitive accelerometer with a noise level of 350ng/√Hz, bandwidth of 4.5kHz, and 135 dB open loop dynamic range at 1Hz bandwidth. The accelerometer was designed in a mode-tuning structural platform. This platform is developed to address the issue between sensitivity and bandwidth for the low-noise capacitive in-plane accelerometers. The platform proposes to...
The characterization of supra-threshold stochastic resonance (SSR) in which we add noise in an array of N elements, has been discussed. Previous work on SSR was carried out for the calculation of cross correlation co-efficient for uniform signal with uniform distributed noise and Gaussian signal with Gaussian distributed noise. But there is always uncertainty about the distribution of real data. So,...
This paper presents an analytical comparison of two commonly used read-out structures for pulse oximeters, in a wearable application context. The objective is to analyze and highlight the trade-off between the SNR and the power consumption. The proposed analysis clarifies, by the means of analytical equations, the impact of the input photocurrent, the photodiode parasitic capacitance, the feedback...
Variability of Low Frequency Noise (LFN) and Random Telegraph Noise (RTN) is a main concern in analog CMOS integrated circuits. For instance circuits such as current reference, SRAM, ring oscillators are ultimately limited by noise level and mismatch. In this work, CORNER DOPED devices have been fabricated, measured, and finally compared with standard CMOS technology with particular emphasis on weak...
We discuss the thermal noise and the effect of input noise sources on the output noise of plasmonic Field Effect Transistors operating in a quasi-ballistic regime. The input noise strongly affects the output noise at large signals and when the detectors operate near the threshold, where the highest responsivity is reached. In the detection regime with a finite drain current, 1/f noise becomes dominant...
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