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Design of amplifier circuits with low-noise operable at low-power to be used, especially for implantable neural interfaces, remains a huge challenge. This research paper presents the design of a low-noise low-voltage neural recording amplifier suitable for amplifying local field potentials and extracellular action potentials so as to meet the end requirement of an implantable neuro-medical system. Critical performance parameters of the smaller circuit blocks of the complete neural amplifier architecture have been found with the help of detailed mathematical analysis and then verified by the simulations conducted using 0.18 µm 4M1P foundry Semi-conductor Laboratory N-well process. The neural amplifier design proposed in this paper passes neural signal of interest with a mid-band gain of 49.9 dB over a bandwidth of 5.3 Hz–8.6 kHz, draws only 11.5 µW of power from ±0.9 V supply voltage, and exhibits an input-referred noise of 2.6 µVrms with a noise efficiency factor of 2.27. The area consumed by the proposed neural amplifier architecture is 0.192 mm2. The complete circuit design carried out in this paper should prove to be useful in equipment for the diagnosis of neurological disorders. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new in-plane XYθz nano-positioning stage that utilizes piezoelectric actuators and flexure mechanisms. The proposed stage has an aperture and is compact, which facilitates its application in measurement equipment, especially those used for biological specimens. The stage has four piezoelectric actuators and four bridge-type flexure mechanisms, which are used to amplify the small motions produced by the piezoelectric actuators. This paper describes the modeling and design optimization of the stage, which has X- and Y-direction motion ranges of 300 μm and a θz-direction motion range of ±3.9 mrad. The stage measures 150 × 150 × 23 mm, and its aperture is 50 × 50 mm. [ABSTRACT FROM AUTHOR]

Recent analysis of Gas Puff Imaging (GPI) data from Alcator C-Mod found blob velocities with a modified tracking time delay estimation (TDE). These results disagree with velocity analysis performed using direct Fourier methods. In this paper, the two analysis methods are compared. The implementations of these methods are explained, and direct comparisons using the same GPI data sets are presented to highlight the discrepancies in measured velocities. In order to understand the discrepancies, we present a code that generates synthetic sequences of images that mimic features of the experimental GPI images, with user-specified input values for structure (blob) size and velocity. This allows quantitative comparison of the TDE and Fourier analysis methods, which reveals their strengths and weaknesses. We found that the methods agree for structures of any size as long as all structures move at the same velocity and disagree when there is significant nonlinear dispersion or when structures appear to move in opposite directions. Direct Fourier methods used to extract poloidal velocities give incorrect results when there is a significant radial velocity component and are subject to the barber pole effect. Tracking TDE techniques give incorrect velocity measurements when there are features moving at significantly different speeds or in different directions within the same field of view. Finally, we discuss the limitations and appropriate use of each of methods and applications to the relationship between blob size and velocity. [ABSTRACT FROM AUTHOR]

This paper proposes a novel compliant underactuated gripper with multiple working modes. Based on the pseudo-rigid-body method, a static analysis of different working modes is carried out, establishing an analytical relationship between the output grasping forces and the input load. For the enveloped grasping mode, an algorithm to determine the static equilibrium position is given. Furthermore, a parametric optimization algorithm based on gradient descent is designed to obtain the maximum grasping forces. The effectiveness of the multiple grasping modes, the grasping force models, and the optimization algorithm are verified by a dynamic simulation package and finite element analysis as well as by experimental tests. Finally, various grasping experiments are conducted to further validate each working mode, the stability of grasping, and the ability to protect fragile objects. [ABSTRACT FROM AUTHOR]

A simple and robust technique for directly measuring the loop gain and bandwidth of a phase- locked loop (PLL) is proposed. This technique can be used for the real-time measurement of the real loop gain in a closed PLL without breaking its locking state. The agreement of the measured loop gain and theoretical calculations proves the validity of the proposed measurement technique. This technique with a simple configuration can be easily expanded to other phase-locking systems whose loop gain and bandwidth should be measured precisely. [ABSTRACT FROM AUTHOR]

Multi-axis measurement of motion is indispensable for characterization of dynamic systems and control of motion stages. This paper presents an optical beam deflection-based measurement system to simultaneously measure three-axis out-of-plane motion of both micro- and macro-scale targets. Novel strategies are proposed to calibrate the sensitivities of the measurement system. Subsequently the measurement system is experimentally realized and calibrated. The system is employed to characterize coupled linear and angular motion of a piezo-actuated stage. The measured motion is shown to be in agreement with theoretical expectation. Next, the high bandwidth of the measurement system has been showcased by utilizing it to measure coupled two-axis transient motion of a Radio Frequency Micro-Electro-Mechanical System switch with a rise time of about 60 μs. Finally, the ability of the system to measure out-of-plane angular motion about the second axis has been demonstrated by measuring the deformation of a micro-cantilever beam. [ABSTRACT FROM AUTHOR]

Aiming at reducing the estimation error of the sensor frequency response function (FRF) estimated by the commonly used window-based spectral estimation method, the error models of interpolation and transient errors are derived in the form of non-parameter models. Accordingly, window effects on the errors are analyzed and reveal that the commonly used hanning window leads to smaller interpolation error which can also be significantly eliminated by the cubic spline interpolation method when estimating the FRF from the step response data, and window with smaller front-end value can restrain more transient error. Thus, a new dual-cosine window with its non-zero discrete Fourier transform bins at −3, −1, 0, 1, and 3 is constructed for FRF estimation. Compared with the hanning window, the new dual-cosine window has the equivalent interpolation error suppression capability and better transient error suppression capability when estimating the FRF from the step response; specifically, it reduces the asymptotic property of the transient error from O(N−2) of the hanning window method to O(N−4) while only increases the uncertainty slightly (about 0.4 dB). Then, one direction of a wind tunnel strain gauge balance which is a high order, small damping, and non-minimum phase system is employed as the example for verifying the new dual-cosine window-based spectral estimation method. The model simulation result shows that the new dual-cosine window method is better than the hanning window method for FRF estimation, and compared with the Gans method and LPM method, it has the advantages of simple computation, less time consumption, and short data requirement; the actual data calculation result of the balance FRF is consistent to the simulation result. Thus, the new dual-cosine window is effective and practical for FRF estimation. [ABSTRACT FROM AUTHOR]