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A Methodology to Minimize Power of Receivers for Internet of Things
, Ph.D. Dissertation Sharif University of Technology ; Atarodi, Mojtaba (Supervisor) ; Sadughi, Sirus (Supervisor)
Abstract
The number of connected devices through the internet of things is increasing rapidly, which leads to adopting different communication technologies to provide connectivity of this large number of devices. The used communication technologies can be classified into the local area network, low-power wide-area network (LPWAN), and cellular network technologies. The receiver power has a critical role in the total power consumption of utilized transceiver chips in these technologies. Radiofrequency (RF) front-ends are often significant power-consuming parts of integrated receivers. Therefore, system-level design in which the overall specifications are distributed among RF front-end building blocks...
Systematic Design of Low Power Flash ADC
, Ph.D. Dissertation Sharif University of Technology ; Sadughi, Sirus (Supervisor) ; Sharifkhani, Mohamad (Co-Advisor) ; Atarodi, Mojtaba (Co-Advisor)
Abstract
Considering the drastical increasing of greenhouse gases in the atmosphere, especially carbon dioxide, reduction of these gases seems necessary to combat global warming. Fossil fuel power plants are one of the main sources of CO2 emission. In this thesis, CO2 capture from a natural gas fired combined cycle power plant using different oxygen percent in air feed is studied. Aspen Plus was used to evaluate the effect of this capture technology on the plant efficiency and energetic parameters of the system. Aspen Hysys is used to simulate Amine absorption tower and Air Separation cryogenic tower. Since the oxygen production plant, CO2 capture and transport are cost and energy intensive, the cost...
A low power 1.2 GS/s 4-bit flash ADC in 0.18 μm CMOS
, Article Proceedings of IEEE East-West Design and Test Symposium, EWDTS 2013 ; 2013 ; 9781479920969 (ISBN) ; Sharifkhani, M ; Sadughi, S ; Sharif University of Technology
2013
Abstract
A low power 4-bit flash ADC is proposed. A new power reduction technique is employed which deactivates the unused blocks in the converter structure in order to reduce the power consumption. A new method for built-in threshold voltage generation together with a new offset calibration method is used to further reduce the power consumption in the converter. Monte-Carlo simulation shows that after calibration both the INL and the DNL are lower than 0.35 LSB. The converter achieves 3.5 effective number of bits (ENOB) at 1.2 GS/s sampling rate after the offset calibration is performed. It consumes 10 mW from a 1.8 V supply, yielding a FoM of 560 fJ/conversion.step in a 0.18 μm standard CMOS...
A 4-Bit, 1.6 GS/s low power flash ADC, based on offset calibration and segmentation
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 60, Issue 9 , 2013 , Pages 2285-2297 ; 15498328 (ISSN) ; Sharifkhani, M ; Sadughi, S ; Sharif University of Technology
2013
Abstract
A low power 4-bit, 1.6 GS/s flash ADC is presented. A new power reduction technique which masks the unused blocks in a semi-pipeline chain of latches and encoders is introduced. The proposed circuit determines the unused blocks based on a pre-sensing of the signal. Moreover, a reference voltage generator with very low static power dissipation is used. Novel techniques to reduce the sensitivity to dynamic noise are proposed to suppress the noise effects on the reference generator. The proposed circuit reduces the power consumption by 20 percent compared to the conventional structure when a Nyquist rate OFDM signal is applied. The INL and DNL of the converter are smaller than 0.3 LSB after...
A novel design of hybrid-time-interleaved current steering digital to analog converter and its behavioral simulation considering non-ideal effects
, Article Integration ; Volume 69 , 2019 , Pages 321-334 ; 01679260 (ISSN) ; Torkzadeh, P ; Sadughi, S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
This work presents a behavioral model for non-ideal effects in a novel Hybrid time-interleaved digital to analog converter (TIDAC). In Hybrid DACs, both ΔΣ and Nyquist structures are used. In this work, in the Nyquist path, the 2-time-interleaving technique is used and in the ΔΣ path, a new structure is proposed to reduce the critical path in the TI delta-sigma modulator (DSM). In conventional TIDSM, adding each channel to the structure leads to increasing the critical path as one full-adder. This, in turn, decreases the speed of modulator since a single feedback loop is utilized to compute the running sum of the input signals. In this work, a new type of poly-phase decomposition is...
A fully linear 5.2 GHz - 5.8 GHz digitally controlled oscillator in 65-nm CMOS technology
, Article Microelectronics Journal ; Volume 90 , 2019 , Pages 48-57 ; 00262692 (ISSN) ; Torkzadeh, P ; Sadughi, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
A low-power fully linear integrated CMOS LC-based Digitally Controlled Oscillator is presented. The DCO operates in 5.2 GHz to 5.8 GHz range for using in IEEE 802.11a wireless applications. The system has been designed using 65 nm CMOS technology and 1.2 V supply voltage. By applying a proposed filter in DCO architecture −133.41 dBc/Hz phase noise at 1 MHz offset frequency from the fundamental carrier is achieved. The code generator and digital to analog converter designed to provide the high precision voltage required for fine-tuning. The output frequency swept through 10 control bits with 100 KHz resolution. The measured RMS jitter (∑ [1 KHz – 2 GHz]) from 5.8 GHz carrier is 1.65 fs. The...
A system-level design method for RF receiver front-end with low power consumption
, Article Analog Integrated Circuits and Signal Processing ; 2021 ; 09251030 (ISSN) ; Atarodi, M ; Sadughi, S ; Sharif University of Technology
Springer
2021
Abstract
Due to wireless communication’s rapid growth, the need for low power integrated transceivers is increasing. The receiver power is a major limiting factor, and the radio frequency (RF) front-end is often its significant power consuming part. Therefore, system-level design in which the overall specifications are distributed among RF front-end building blocks such that the minimum total power is consumed is crucial. A complete system-level design method for a low power RF front-end is presented in this paper. For this purpose, the performance of each block is modeled by its current and overdrive voltage. An analytical associated with a search-based optimization technique is employed to derive...
A 7 bit, 3 GHz bandwidth random-time-interleaved-hybrid DAC using a novel self-healing structure for DCE in 65 nm CMOS technology
, Article AEU - International Journal of Electronics and Communications ; Volume 134 , 2021 ; 14348411 (ISSN) ; Torkzadeh, P ; Sadughi, S ; Sharif University of Technology
Elsevier GmbH
2021
Abstract
The application of time-interleaved structure leads to new amplitude and time errors while reducing many static and dynamic errors. In this case, both amplitude and time error are decreased by circuit structures integrated into a 7-bit DAC. In the present study, a new structure was proposed based on the randomization of two-interleaved paths in order to reduce the amplitude error, which can be extended to the N-channels-interleaved. In order to reduce the cycle-duty-error, a self-correction structure based on calculating the amplitude of the error before and measuring the time of this error along with the passage of the main signal through the output multiplexer is provided. The advantage of...
Study of Crystalline Structure in Random Co-polypropylene and Its Influence on Melting Behavior
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Asgari, Sirus (Supervisor)
Abstract
In today’s world the growth in population make food production and also the packaging industry increase. Finding new ways to enhance the efficiency of packaging is become so important beyond researchers. As the randomized co-polypropylene is the most suitable materials for this industry many attempts have been made to control its melting behavior with the aim of expanding their application in the packaging industry. The study in this field indicate the dependence of the melting behavior on the structural characteristics of the material such as molecular mass, chain structure, type of crystalline structure, and the amount of dispersion of the crystals thickness. Due to the lack of proper...
A novel architecture of pseudorandom dithered MASH digital delta-sigma modulator with lower spur
, Article Journal of Circuits, Systems and Computers ; Volume 25, Issue 7 , 2016 ; 02181266 (ISSN) ; Frashidi, E ; Sadughi, S ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2016
Abstract
A Digital Delta Sigma Modulator (DDSM) is a Finite State Machine (FSM); it is implemented using finite precision arithmetic units and the number of available states is finite. The DDSM always produces a periodic output signal when the input is constant. This paper proposes a novel method of applying periodic dither to a DDSM in order to obtain minimized spurious tones. The effects of adding the pseudorandom dither signal in different stages within the proposed Multi-Stage noise Shaping (MASH) modulator are expressed in the equations, and the results are compared. We present results regarding the periodicity of the quantization noise produced by a MASH modulator with a constant input and a...
Control of Size of Graphene Domain Synthesized by Chemical Vapor Deposition
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Sirus (Supervisor) ; Karimi Sabet, Javad (Supervisor)
Abstract
The chemical vapor deposition (CVD) of graphene from methane on a copper substrate is the most promising method for production of large-area graphene films. There have been long-standing challenges in this field such as controlling the graphene coverage, film quality, the number of layers, and the nucleation density of graphene domain. These challenges can be overcome by developing a fundamental understanding of the graphene growth process. The main aim of this study is to control nucleation density of graphene domains. Chemical vapor deposition (CVD) graphene is polycrystalline, and grain boundaries in graphene film have been identified to degrade the properties of graphene as a membrane...
Design of Front End of UWB Receivers
, M.Sc. Thesis Sharif University of Technology ; Sadughi, Sirous (Supervisor) ; Haj Sadeghi, Khosro (Supervisor)
Abstract
This Project deals with the Low-Noise Amplifier (LNA) and High-Q Band-Stop filter for a UWB receiver designed using a standard 0.18um CMOS process. These LNAs cover the frequency band of 1 to 11 GHz. Stringent sensitivity and low noise figure requirements, presence of strong in-band interferers and the ultra wide band operation are the main design challenges of the receiver and the LNA. In this thesis, Three LNAs with good performance and good input matching are designed. Two of them used Common gate topology with gm-Boosting technique to reduce the noise figure. Also because of wide bandwidth requirement, the bandwidth of these LNAs is improved by Inductive shunt and series peaking...
Design of an N-Path Tunable Bandpass Filter for RF Range
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor) ; Sadughi, Sirous (Supervisor)
Abstract
A high-Q tunable bandpass filtered amplifier structure is proposed which is based on N-path Q enhancement. Using Fourier series analysis, frequency response of an N-path filter and aliasing effect of this filter is achieved. This effect is caused by frequency translation to bandpass frequency as harmonic fold back (HFB). It is shown that using an additional N-path filter with the same clock frequency but different clock phase HFB is reduced. The conditions for fold back elimination are derived from Fourier series expansions for switched signals. In order to realize HFB reduction and increasing stop-band rejection and Q factor, an LNA associated with N-path filter is added to each of the...
Synthesis of Graphene Oxide and Graphene Oxide Membrane for Separation of Gas Mixtures
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Sirus (Supervisor) ; Karimi Sabet, Javad (Supervisor) ; Mousavi, Abbas (Co-Advisor)
Abstract
Thin film graphene oxide(GO) membranes have been promising potential for gas purification due to thin lamellar microstructure, stable a few atom thick layers and very short intersheet distances. In this research, the nanoporous graphene oxide membranes have been prepared by vacuum and pressurized ultrafiltration on the modified polyacrylonitryle(mPAN) sublayer for helium separation from Nitrogen and carbon dioxide gas mixture. The separation performance of synthesized GO membrane was controlled by varying parameters such as concentration of stabilized aqueous GO solution, pores size range of support and its surface properties, centrifuge time, applied pressure after synthesis, humidity,...
Investigating the Effect of Hot Rolling of Ti-6Al-4V Alloy Containing Titanium Carbonitride Particles and Boron Addition on Microstructure Evolution and Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Ziaei Moayyed, Ali Akbar (Supervisor) ; Asgari, Sirus (Supervisor) ; Abbasi, Mehdi (Supervisor)
Abstract
In this thesis, two ingot of Ti-6Al-4V alloy containing titanium carbonitride particle, one with adding boron and the other without boron were fabricated by VIM furnace and using graphite crucible. Boron was added for the purpose of investigating its effect on microstructural evolution and mechanical properties. By Processing Casting ingots under TMP and heat treatment sequences, strips with 3 millimeter thickness were produced. In secondary rolling stage, rolling temperature was considered variable in alpha and alpha + beta phase field and its effect was studied on microstructural characteristics and mechanical properties. In as-rolled condition, it was found that increasing the rolling...
Study the Rheological Behavior and the Pour Point Waxy Crude Oil
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Sirus (Supervisor) ; Jafaribehbahani, Tarane (Supervisor) ; Khorashe, Farhad (Supervisor) ; Ramezani saadat abadi, Ahmad (Co-Advisor)
Abstract
Wax deposition crude oils, with high pour point causes, many problems arise in production, transfer and storage. In this project, wax appearance temperature of three samples of crude oil caculated, using techniques viscometer. Maximum absolute error on oil.no2 was with a value of 0.559% and the results had in good agreement with experimental data. By using the rheometer MCR301, for three crude oil samples, steady shear tests and sweep time tests was done. Flow diagrams were obtained. According to wax appearance temperature (WAT) of each samples, diagrams shear stress versus shear rate are nonlinear at low temperatures than WAT. Crude oil shows non-newtonian behavior. Arrhenious model,...