High accuracy analog Hall probe

We report high slope efficiency and low noise characteristics in a distributed feedback (DFB) laser lasing at 1.3 /spl mu/m with narrow beam divergence by employment of a laterally tapered active stripe over the whole cavity. This tapered structure is designed to realize narrow beam divergence, low threshold current, and high longitudinal mode selectivity. The fabricated tapered-active-stripe DFB lasers demonstrated of 9.20/spl times/13.40 and a record slope efficiency, for a narrow beam DFB laser, of 0.59 mW/mA. The temperature characteristics from -10/spl deg/C to 85/spl deg/C shows high output power at high temperature, stable single longitudinal mode oscillation and stable far-field patterns. Furthermore, for the first time ever, a low relative intensity noise characteristic of under -155 dB/Hz has been realized when butt-coupling into a single-mode fiber.

We propose and experimentally demonstrate a photonic millimeter-wave frequency divider based on a super-harmonic injection-locked optoelectronic oscillator (OEO) and an optical frequency comb. The optical frequency comb generator is incorporated into an OEO loop to create broadband comb lines with low noise. By injecting a millimeter-wave with frequency around N times of the fundamental oscillating frequency f0 of the OEO, the injection signal can be down-converted to an intermediate frequency (IF) signal close to the oscillating frequency of the OEO. The free running OEO is synchronized with the IF signal via an injection locking mechanism. Consequently, it forms an injection-locked frequency divider as the frequency ratio between the injection signal and OEO's output signal is precisely equal to N. We carry out an experiment to divide the 45 GHz signal into 7.5 GHz and the experimental results agree well with the theoretical analysis. By changing the frequency of the injection signal, division ratio from 2 to 5 is also demonstrated on one setup. Due to the broadband spectra of the optical comb and low phase noise characteristics of the OEO, it is potential to realize very large division ratio and low phase noise for multiple input frequencies mf 0 .

Single-layered perpendicular recording media with high resolution and low noise characteristics, which can be used for 10 Gb/in/sup 2/ level magnetic recording, have been developed. Noise characteristics of highly oriented CoCr/sub 19/Pt/sub 10/ media are improved, by employing CoCr/sub 35//TiCr/sub 10/ dual-underlayer, by reducing magnetic crystal grain diameter, and by adding Ta to the magnetic layer. A linear recording density resolution (D/sub 50/) value of 260 kFCI and a S/sub 0//N ratio of 36 dB are confirmed for the low noise 50-nm-thick CoCr/sub 19/Pt/sub 10/Ta/sub 2/ dual-underlayer medium using a flying MR head at magnetic spacing of 40 nm.

The Charge Sensitive Amplifier (CSA) is the key module of the front-end electronics of various types of Silicon detectors and most radiation detection systems. High gain, stability, and low input noise are the major concerns of a typical CSA circuit in order to achieve amplified susceptible input charge (current) for further processing. To design such a low-noise, stable, and low power dissipation solution, a CSA is required to be realized a complementary metal-oxide-semiconductor (CMOS) technology with a compact design. This research reports a low-noise highly stabile CSA design considerations for Silicon detectors applications, which has been designed and validated in TSMC 0.35um CMOS process. In a typical CSA design, the detector capacitance and the input transistor’s width are the most dominating parameters for achieving low noise performance. Therefore, the Equivalent Noise Charge (ENC) with respect to those parameters has been optimized, for a set of detector capacitance from 0.2pF – 2pF. However, the parallel noise of the feedback was removed by adopting a voltage-controlled NMOS resistor, which in turn helped to achieve high stability of the circuit. The simulation results provided a baseline gain of 9.92mV/fC and show that ENC was found to be 42.5e – with 3.72 e – /pF noise slope. The Corner frequency exhibited by the CSA is 1.023GHz and the output magnitude was controlled at -56.8dB; it dissipates 0.23mW from with a single voltage supply of 3.3V with an active die area of 0.0049 mm 2 .

Compatibility of low noise characteristic and offset stability is essential for a magnetometer to be applicable for measurements of dc and low-frequency magnetic fields. Fundamental mode orthogonal fluxgate (FM-OFG) magnetometer has advantages in its compact design and low noise characteristic, whereas its disadvantage is the offset drift which is unacceptably large for such measurement. An effective technique called bias switching has been proposed to suppress and stabilize the offset of open-loop FM-OFG magnetometers, yet when it is adopted with a feedback configuration to obtain better linearity, it increases noises attributed to the convergence process. In this paper, we present a design of sensor driving electronics of FM-OFG magnetometers to solve this problem and achieve compatibility of low noise and stable offset characteristics with a feedback configuration. The efficacy of the design was verified through various performance evaluations.

The experiences of stress are common to all living things. Noise is one of the most widespread sources of environmental stress. Noise is a pervasive aspect of many modern community and work environments. So, it is important to consider noise when we design human-oriented products. This study investigates the responses of electrocardiogram (ECG) and eye tracker data in order to evaluate the direct effects of low, middle, and high frequency noise on the two main physiological stress axes: the autonomic nervous system, and cognitive responses for a human-oriented product design. A subject was exposed to low (100 Hz), middle (1000 Hz), and high frequency (100000 Hz) noise while awake. ECG and eye tracker data were collected during noise exposure. Sympathetic nervous system (SNS) activity was less in the low and high frequency noise ranges compared to the no sound. On the other hand, parasympathetic nervous system (PNS) activity was greater in the low and high frequency noise ranges than the SNS activity in the no sound. The cognitive responses or latency saccadic eye movement (LSEM), in low or high frequency noise was greater than that in the no sound. And results of EEG and eye movement were statistically significant in low and high frequency noise (r > 0.93, p < 0.05). The findings of this study indicate that the stress induced by low frequency noise is as stressful as the stress induced by high frequency noise. Additionally, utilizing eye tracker data and acquiring the LSEM is useful in the analysis of human stress responses during various stressful situations in addition to the analysis of human stress responses during noise exposure.

This paper describes the progress in analysis of the ITER plasma vertical stabilisation (VS) system since its design review in 2007–2008. Two indices characterising plasma VS were studied. These are (1) the maximum value of plasma vertical displacement due to free drift that can be stopped by the VS system and (2) the maximum root mean square value of low frequency noise in the dZ/dt measurement signal used in the VS feedback loop. The first VS index was calculated using the PET code for 15 MA plasmas with the nominal position and shape. The second VS index was studied with the DINA code in the most demanding simulations for plasma magnetic control of 15 MA scenarios with the fastest plasma current ramp-up and early X-point formation, the fastest plasma current ramp-down in a divertor configuration, and an H to L mode transition at the current flattop. The studies performed demonstrate that the VS in-vessel coils, adopted recently in the baseline design, significantly increase the range of plasma controllability in comparison with the stabilising systems VS1 and VS2, providing operating margins sufficient to achieve ITER's goals specified in the project requirements. Additionally two sets of the DINA code simulations were performed with the goal of assessment of the capability of the PF system with the VS in-vessel coils: (i) to control the position of runaway electrons generated during disruptions in 15 MA scenarios and (ii) to trigger ELMs in H-mode plasmas of 7.5 MA/2.65 T scenarios planned for the early phase of ITER operation. It was also shown that ferromagnetic structures of the vacuum vessel (ferromagnetic inserts) and test blanket modules insignificantly affect the plasma VS.

This letter presents a low-noise and high-gain CMOS mixer that uses a simple dynamic current-bleeding (DCB) technique. The conventional static current-bleeding (SCB) technique has high conversion gain and low noise figure at a high intermediate frequency (IF) but also has moderately high direct-mechanism flicker noise. Meanwhile, the conventional DCB technique possesses completely opposite characteristics. The proposed DCB technique obtains not only low direct flicker noise and low noise figure at high IF, but also has high conversion gain by combining only the advantageous features of both conventional techniques. Measurement results show a conversion gain of 21.2 dB and a noise figure of 16.3 dB at 10 kHz and 5.6 dB at 10 MHz, while the mixer consumes 4.2 mW at a 1.2 V supply voltage. It was implemented in a 0.11-μm CMOS process with a chip area of 0.8 × 0.8 mm2. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1267–1271, 2017

Under the laser tracker measurement of angle subsystem environment,signal acquisition system of laser tracker incremental encoder based on FPGA was designed in this paper. The FPGA in this system was mainly responsible for the encoder signal acquisition, processing, and generating timing signals, data caching mechanism and asynchronous output of the data. This paper detailedly introduced quadrupler frequency, phase discrimination, counting, latches, and UART asynchronous serial port output sub-modules in the process of signal acquisition of FPGA, which was implemented by Verilog HDL language. Online logic analyzer of the Quartus software acquired the value of encoder signal in real time, and the rationality of the design was verified ultimately.

In order to test the effect of noise on the various parameters of the SAECG, 83 patients underwent three consecutive recordings at different noise levels. The high noise (HN) recordings had a noise level of 0.60-0.74 microV, the intermediate noise (IN) had 0.31-0.59 microV, and the low noise (LN) had < or = 0.30 microV. For the calculation of noise we used the standard deviation of the mean noise of the composite lead high pass filtered at 40 Hz. The recordings were compared using time-domain, frequency-domain, and spectrotemporal analysis. The time-domain parameters of the LN recordings, using 25-Hz, 40-Hz, and 60-Hz high pass cutoffs, were significantly different from those of the HN or IN recordings (P < 0.05). In the frequency-domain analysis, significant differences were found in some of the parameters of the LN compared to the HN. The spectrotemporal analysis of the X and Z leads also showed significant differences among the LN and the other recordings. In the time-domain analysis, both at 40 Hz and 25 Hz, there were more abnormal LN compared to the HN recordings (P < 0.05). In the spectrotemporal analysis, there were significantly more abnormal HN and IN recordings compared to the LN (P < 0.001 and P < 0.01, respectively). Therefore, the level of noise, even within the acceptable range, can significantly affect the SAECG. In the time domain at the lower noise levels the parameters become more abnormal, while the opposite seems to occur in the spectral and the spectrotemporal analysis.

Micro-Hall sensors with high sensitivity, low noise, and high thermal stability, 5 μm square, are fabricated using pseudomorphic Al0.3Ga0.7As/GaAs/InyGa1-yAs (0.2 ≤ y ≤ 0.3) heterostructures with Si-doped channels. The structures were optimized for thermal stability using a calculation of the self-consistent solution of Schrodinger-Poisson equations and Fermi-Dirac statistics in Hartree approximation. The optimized structure based on a Si-δ-doped 144 A In0.2Ga0.8As quantum well embedded into uniformly doped GaAs channel showed thermal drifts of only 90 ppm·K−1 in current drive mode and 192 ppm K−1 in voltage drive mode. The measurements of the absolute magnetic sensitivity and the low frequency noise were done. The micro-Hall sensor, optimized for thermal drift, is able to resolve the magnetic field of 438 nT.

We have proposed and demonstrated the generation of a high-repetition-rate ultrashort pulse with long-term stability and low noise based on a harmonic mode-locked (HML) figure-9 fiber laser. Different HML orders from the 2nd to the 13th are generated by adjusting the pump power, net dispersion, and wave plate angles. A 2-GHz HML pulse is obtained with a 155-MHz fundamental repetition rate in a Yb-doped fiber laser, and the corresponding supermode suppression level is as high as 50 dB. The average power of the output pulse is nearly 200 mW, and the compressed pulse duration is 535 fs. To the best of our knowledge, 2 GHz and 196 mW represent, respectively, the highest repetition rate and output power in a figure-9 fiber laser. This work offers a potential pathway to achieve high-repetition-rate ultrashort pulses in the GHz range with high power and low noise levels.

Cownose rays have excellent characteristics as the fish with oscillating pectoral fins. Therefore, in order to construct bionic fish prototype with high efficiency, low noise and high stability characteristics, cownose rays is chosen as the prototype in bionic research. In the paper, simplified flapping kinematic model is established based on the study of the characteristic of cow rays' pectoral fins. The mechanism characteristics and motion feature of the Robo-rayI-IV generation robotic fish mimicking cownose rays are summarized, and the shortcomings in the current design is analyzed. Then, optimization design ideas of heaving and pitching airfoil based on space parallel mechanism with two degree of freedom are proposed in the design of pectoral fin skeleton. The feasibility of new pectoral fin skeleton is verified through simulation. Bionic pectoral fin is constructed and processed. Finally, experiments were carried out and the rationality of the optimal design is verified. Experiments shows that the new pectoral fin skeleton has good active and passive flexible deformation capacity, and robotic fish with new pectoral fin has better propulsion performance than Robo-rayIV while maintaining the high mobility of the premise.

Effects of shallow trench isolation on low frequency noise characteristics of source-follower transistors in CMOS image sensors

Integrally geared multistage centrifugal compressors have been widely used in many industries. The design of the new compressor is very complicated and needs a reliable design process. This paper discussed the development of a high efficiency integrally geared driven centrifugal compressor for industrial applications. An inhouse program was used to design the centrifugal compressor through aerodynamic and structural optimization. CFD (Computational Fluid Dynamics) is a very important tool for centrifugal compressor design. CFD can help compressor design and perform three-dimensional optimization to further optimize the compressor. The compressor stage matching is also impact the overall compressor performance. The good stage match is very important to make the design success. The Finite Element Analysis (FEA) was used to verify the structure integrity. The CFD and FEA (Finite Element Analysis) analysis are performed to obtain a final compressor performance and to make sure to have a robust operation. The centrifugal compressor has the characteristics of high efficiency, no resonance, and low noise. The designed compressor prototype was built and performance tests were conducted. The performance test results demonstrated that the analytical are fairly agreed with experimental results. The development process and tools are successfully used in the compressor design. The design process can be used for future compressor development.