Electronics
A. Mouri Zadeh Khaki; E. Farshidi
Articles in Press, Accepted Manuscript, Available Online from 30 April 2020
Abstract
In this paper, a novel continuous-time 1-1 MASH ∆∑ Time-to-digital converter (TDC) is presented. Since the proposed design utilizes 12-bit quantizer based on Gated Switched-Ring Oscillator (GSRO) for both stages, it has been implemented all-digitally. By using a novel structure, only one multi-bit ...
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In this paper, a novel continuous-time 1-1 MASH ∆∑ Time-to-digital converter (TDC) is presented. Since the proposed design utilizes 12-bit quantizer based on Gated Switched-Ring Oscillator (GSRO) for both stages, it has been implemented all-digitally. By using a novel structure, only one multi-bit counter is employed for both stages, therefore the required hardware for implementation of this work is much less than conventional TDCs. As a result, complexity, chip area and power consumption would decrease considerably. We implemented the proposed design prototype on an Altera Stratix IV FPGA board. Measured results demonstrate that although this work uses less complex architecture in comparison with previous works, it provides appropriate performance such as 60.7 dB SNR within 8 MHz signal bandwidth at 400 MHz sampling rate while consuming 2.79 mW that reveals suitability of the proposed TDC to be incorporated in fast and accurate applications such as ADPLLs and high-resolution photoacoustic tomography.
Electronics
Z. Kordrostami; S. Hamedi; F. Khalifeh
Articles in Press, Corrected Proof, Available Online from 01 November 2019
Abstract
In this paper, two developed designs of InGaAs/InAlAs high electron mobility transistors (HEMTs) have been studied. The proposed laterally contacted HEMTs satisfy the desired high frequency characteristics and are good candidates for high frequency applications. Two kinds of HEMTs have been designed ...
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In this paper, two developed designs of InGaAs/InAlAs high electron mobility transistors (HEMTs) have been studied. The proposed laterally contacted HEMTs satisfy the desired high frequency characteristics and are good candidates for high frequency applications. Two kinds of HEMTs have been designed and simulated: single-gate laterally contacted HEMT (SGLC-HEMT) and double-gate laterally contacted HEMT (DGLC-HEMT). The proposed SGLC-HEMT exhibits 111 GHz current-gain cut-off frequency. By using double-gate design, the current-gain cut-off frequency has been increased to 256 GHz. The simulation results show that the maximum oscillation frequency for the proposed SGLC and DGLC HEMTs, are 410 GHz and 768 GHz, respectively. Maximum value of transconductance (gm) for SGLC-HEMT is obtained 620 mS/mm while it is 1130 mS/mm for DGLC-HEMT.
Electronics
F. Abdi; P. Amiri; M.H. Refan
Volume 7, Issue 1 , Winter and Spring 2019, , Pages 19-26
Abstract
Adaptive algorithm adjusts the system coefficients based on the measured data. This paper presents a dichotomous coordinate descent method to reduce the computational complexity and to improve the tracking ability based on the variable forgetting factor. Vedic mathematics is used to implement the multiplier ...
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Adaptive algorithm adjusts the system coefficients based on the measured data. This paper presents a dichotomous coordinate descent method to reduce the computational complexity and to improve the tracking ability based on the variable forgetting factor. Vedic mathematics is used to implement the multiplier and the divider operations in the VFF equations. The proposed method decreases the area and increases the computation speed. The linear exponentially weighted recursive least squares as the main algorithm is implemented in many applications such as the adaptive controller, the system identification, active noise cancellation techniques, and etc. The DCD method calculates the inverse matrix in the ERLS algorithm and decreases the resources used in the field-programmable gate array, also the designer can use the cheaper FPGA board to implement the adaptive algorithm because the method doesn't need lots of resources. The proposed method leads to implementing complex algorithms with simple structures and high technology. The proposed method is implemented with ISE software on the Spartan 6 Xilinx board. The proposed algorithm calculates the multiplication result with less than 15ns time and reduces the used FPGA resources to lower than 20% as compared with the classic RLS.
Electronics
M. Karbalaei; D. Dideban; N. Moezi
Volume 7, Issue 1 , Winter and Spring 2019, , Pages 27-34
Abstract
In this work, a dual workfunction gate-source pocket-retrograde doping-tunnel field effect transistor (DWG SP RD-TFET) is proposed and investigated. DWG SP RD-TFET is a Silicon-channel TFET with two isolated metal gates (main gate and auxiliary gate) and a source pocket in the channel close to the source-channel ...
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In this work, a dual workfunction gate-source pocket-retrograde doping-tunnel field effect transistor (DWG SP RD-TFET) is proposed and investigated. DWG SP RD-TFET is a Silicon-channel TFET with two isolated metal gates (main gate and auxiliary gate) and a source pocket in the channel close to the source-channel junction to increase the carrier tunneling rate. For further enhancement in the tunneling rate, source doping near the source-channel junction, i.e., underneath the auxiliary gate is heavily doped to create more band bending in energy band diagram. Retrograde doping in the channel along with auxiliary gate over the source region also improve device subthreshold swing and leakage current. Based on our simulation results, excellent electrical characteristics with ION/IOFF ratio > 109, point subthreshold swing (SS) of 6 mV/dec and high gm/ID ratio at room temperature shows that this tunneling FET can be a promising device for low power applications.
Electronics
J. Khosravi; M. Shams Esfandabadi; R. Ebrahimpour
Volume 6, Issue 2 , Summer and Autumn 2018, , Pages 263-271
Abstract
There are numerous applications for image registration (IR). The main purpose of the IR is to find a map between two different situation images. In this way, the main objective is to find this map to reconstruct the target image as optimum as possible. Needless to say, the IR task is an optimization ...
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There are numerous applications for image registration (IR). The main purpose of the IR is to find a map between two different situation images. In this way, the main objective is to find this map to reconstruct the target image as optimum as possible. Needless to say, the IR task is an optimization problem. As the optimization method, although the evolutionary ones are sometimes more effective in escaping the local minima, their speed is not emulated the mathematical ones at all. In this paper, we employed a mathematical framework based on the Newton method. This framework is suitable for any efficient cost function. Yet we used the sum of square difference (SSD). We also provided an effective strategy in order to avoid sticking in the local minima. As one of the fundamental drawback of mathematical-based optimization methods, local minima have been managed properly by our new strategy. Scale and rotation – as two variables of the problem- have been treated solely in a different iteration. In other words, in every iteration, one of these variables is actually the only variable of the problem as the other one is considered constant. Simulation results indicate the effectiveness of the proposed model.
Electronics
P. Halvaee; M.S. Beigi
Volume 6, Issue 2 , Summer and Autumn 2018, , Pages 209-216
Abstract
In this work, porous nanoparticles of ferrite cobalt were prepared by dissolving CoCl2.6H2O and FeCl3 in ethylene glycol in a hydrothermal process. Using ethylene glycol instead of DI water as a solvent would cause to provide porous structure of ferrite cobalt. 0.05 ml of colloidal fluid of fabricated ...
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In this work, porous nanoparticles of ferrite cobalt were prepared by dissolving CoCl2.6H2O and FeCl3 in ethylene glycol in a hydrothermal process. Using ethylene glycol instead of DI water as a solvent would cause to provide porous structure of ferrite cobalt. 0.05 ml of colloidal fluid of fabricated nanostructure was injected on interdigitated electrodes (IDE) on a printed circuit board (PCB) substrate by a drop casting process. Morphological and structural characterizations of structure were investigated by X-ray diffraction and scanning electron microscopy and the obtained results of analyses show the porous nanostructure of the material. Sensor's performance in detection of gas vapors was evaluated in different temperatures which has the best response (20.38% for 100ppm methanol vapors) for methanol vapors at room temperature. Performance of sensor in selection of methanol vapors, chemical stability and repeatability of that, makes it useful to profit it in different fields and industries.
