Finite-Impulse-Response Digital Differentiators for Midband Frequencies Based on Maximal Linearity Constraints

Maximally linear digital differentiators (DDs) are known for high accuracy in narrow frequency bands centered at the frequency for which they are designed. In this paper, designs of DDs of odd and even lengths having maximal linearity at the middle of the frequency band are presented. Applying the maximal linearity constraints to the magnitude response of a differentiator gives a system of linear equations, which can be solved for the impulse response coefficients of the differentiator. It is observed that the coefficient matrices of these equations are Vandermonde matrices, and this helps in finding the solution of the equations in closed form. Design examples are presented to show the accuracy of the presented designs, and it is observed that even-length designs are more accurate in a significantly wider frequency band as compared with odd-length designs     

Validation of modal/MoM in shielding effectiveness studies of rectangular enclosures with apertures

This paper discusses the validation of Modal/method of moments (MoM) including cases when the apertures are made as big as the wall of the enclosure (equivalent to having one side of the cavity open). The validation is done using field computations involving bodies of arbitrary shape (FEKO), a commercially available code. The results show that Modal/MoM predicts the results close to the analytical results of Robinson et al. Electron. Lett., 32 (17), 1996; Robinson et al., IEEE Trans. Electromagn. Compat., 40 (3), 240-247, 1998 for single-aperture cases and for most double-aperture cases. Also, for the cases of considering oblique incident plane waves, through validation, it has been found that Modal/MoM can predict the shielding effectiveness close to measured results for smaller angles and not for larger angles of incidence due to the edge effects. In this work, the shielding effectiveness is calculated at only one point, the center of the cavity assuming it to be the worst case. This work discovers the limitation of Modal/MoM for certain applications.     

Quantum Transport Simulation of Experimentally Fabricated Nano-FinFET

We have utilized the contact-block-reduction (CBR) method, which we extended to allow a charge self-consistent scheme, to simulate experimentally fabricated 10-nm-FinFET device. The self-consistent CBR simulator has been modified to simulate devices with channels along arbitrary crystallographic orientation. A series of fully quantum-mechanical transport simulations has been performed. First, the fin extension length and doping profile have been calibrated to match the experimental data. The process control window for the threshold voltage as a function of fin extension has been extracted for the considered device. Then, a set of transfer characteristics and gate leakage currents have been calculated for different drain voltages. The simulation results have been found to be in good agreement with the experimental data in the subthreshold regime. The device turn-off and turn-on behavior has been examined for different fin widths: 12 (experimental), 10, 8, and 6 nm. Finally, the subthreshold slope degradation at high temperatures has been studied     

Direction of arrival estimation using adaptive directional time-frequency distributions

Time-frequency distributions (TFDs) allow direction of arrival (DOA) estimation algorithms to be used in scenarios when the total number of sources are more than the number of sensors. The performance of such time–frequency (t–f) based DOA estimation algorithms depends on the resolution of the underlying TFD as a higher resolution TFD leads to better separation of sources in the t–f domain. This paper presents a novel DOA estimation algorithm that uses the adaptive directional t–f distribution (ADTFD) for the analysis of close signal components. The ADTFD optimizes the direction of kernel at each point in the t–f domain to obtain a clear t–f representation, which is then exploited for DOA estimation. Moreover, the proposed methodology can also be applied for DOA estimation of sparse signals. Experimental results indicate that the proposed DOA algorithm based on the ADTFD outperforms other fixed and adaptive kernel based DOA algorithms.     

Taylor series based two-dimensional digital differentiators

A new type of Taylor series based 2-D finite difference approximation is presented, and it is shown that the coefficients of these approximations are not unique. Explicit formulas are presented for one of the possible sets of coefficients for an arbitrary order, by extending the previously presented 1-D approximations. These coefficients are implemented as maximally linear 2-D FIR digital differentiators, and their formulas are modified to narrow the inaccuracy regions on the resultant frequency responses, close to the Nyquist frequencies     

High-power operation of III-N MOSHFET RF switches

We describe a large-signal performance of novel high-power radio frequency (RF) switches based on III-nitride insulated gate metal-oxide semiconductor heterostructure field-effect transistors (MOSHFETs). The maximum switching powers for a single MOSHFET with only 1-mm gate width exceed 50W at 10GHz, more than an order of magnitude higher than those achievable using GaAs transistors. In the ON state, the highest powers are determined by the device peak drain currents, 1-2A/mm for the state-of-the art III-N MOSHFETs; in the OFF state their maximum powers are limited by the breakdown voltage, normally well above 100V. Our experimental data are in close agreement with large-signal simulations and the proposed simple analytical model. We also show that the insulating gate design allows for broader bandwidth and higher switching powers and better stability as compared to conventional Schottky gate transistors.     

Velocity-image model for online signature verification.

In general, online signature capturing devices provide outputs in the form of shape and velocity signals. In the past, strokes have been extracted while tracking velocity signal minimas. However, the resulting strokes are larger and complicated in shape and thus make the subsequent job of generating a discriminative template difficult. We propose a new stroke-based algorithm that splits velocity signal into various bands. Based on these bands, strokes are extracted which are smaller and more simpler in nature. Training of our proposed system revealed that low- and high-velocity bands of the signal are unstable, whereas the medium-velocity band can be used for discrimination purposes. Euclidean distances of strokes extracted on the basis of medium velocity band are used for verification purpose. The experiments conducted show improvement in discriminative capability of the proposed stroke-based system.     

Analysis and Implementation of Multiple–Input, Multiple–Output VBLAST Receiver From Area and Power Efficiency Perspective

This paper presents an analysis of the vertical Bell Laboratories layered space time (VBLAST) receiver used in a multiple-input multiple-output (MIMO) wireless system from the hardware implementation perspective and identifies those processing elements that consume more area and power due to complex signal processing. This paper models a scalable VBLAST receiver based on minimum mean square error (MMSE) nulling criteria assuming a block flat fading channel. After identifying the major area and power consuming blocks, this paper proposes two area and power efficient VLSI architectures for the block that computes pseudoinverse of the channel matrix. This paper discusses different tradeoff issues in both architectures and compares them with the architectures in the literature     

A framework for harmonizing internet of things (IoT) in cloud: analyses and implementation

Internet of Things (IoT) refers to uniquely identifiable entities. Its vision is the world of connected objects. Due to its connected nature the data produced by IoT is being used for different purposes. Since IoT generates huge amount of data, we need some scalable storage to store and compute the data sensed from the sensors. To overcome this issue, we need the integration of cloud and IoT, so that the data might be stored and computed in a scalable environment. Harmonization of IoT in Cloud might be a novel solution in this regard. IoT devices will interact with each other using Constrained Application Protocol (CoAP). In this paper, we have implemented harmonizing IoT in Cloud. We have used CoAP to get things connected to each other through the Internet. For the implementation we have used two sensors, fire detector and the sensor attached with the door which is responsible for opening it. Thus our implementation will be storing and retrieving the sensed data from the cloud. We have also compared our implementation with different parameters. The comparison shows that our implementation significantly improves the performance compared to the existing system.