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A power-efficient LC quadrature VCO for RFID, zigbee and bluetooth standards
, Article Advances in Electrical and Computer Engineering ; Volume 9, Issue 3 , 2009 , Pages 34-38 ; 15827445 (ISSN) ; Atarodi, M ; Sharif University of Technology
2009
Abstract
A multi-band CMOS LC Quadrature Voltage Control Oscillator (QVCO) with minimum power consumption is developed to meet the phase noise and frequency band requirements of RFID, Zigbee and Bluetooth standards. To accomplish the multi-band receiving architecture at low power consumption, current switching technique with optimized cross-coupled transistor sizes has been used. A comprehensive analysis of small signal model for complementary architecture including transistor noise sources and their effects on output phase noise amount has been discussed. Using extracted small signal model, coupled and coupling transistor sizes for minimum power consumption and the least achievable phase noise have...
Inspecting safety level of bluetooth headset radiation in the vicinity of human head: A numerical study
, Article 2013 7th European Conference on Antennas and Propagation, EuCAP 2013 ; 2013 , Pages 1178-1182 ; 9788890701832 (ISBN) ; Ashiri, M ; Hajsadeghi, K ; Hosseinzade, S. N ; Khaligh, H. H ; Sharif University of Technology
2013
Abstract
Bluetooth headsets are one of the popular accessories of mobile phones because of their convenience. It is necessary to assess the impact of electromagnetic waves on the human head when a person is using a headset. In this paper different scenarios closely modeling the situations that a subject may use the headset in real life are simulated. Simulations are performed for two types of materials commonly used to manufacture the headsets, namely silicone and acetal, and for two different orientation angle of the headset on the ear. Specific Absorption Rate (SAR) and path loss values are then obtained for two different environments, the open space and inside a car. SEMCAD-X software is used as a...
Essential design considerations for wireless multi-channel photoplethysmography system
, Article IFMBE Proceedings, 23 November 2008 through 27 November 2008, Antwerp ; Volume 22 , 2008 , Pages 1066-1069 ; 16800737 (ISSN); 9783540892076 (ISBN) ; Mohd Ali, M. A ; Zahedi, E ; Sharif University of Technology
2008
Abstract
The developed wireless multi-channel PPG system comprises tiered communication subsystem with two sensor modules and a single base module. The sensor modules process the input signals simultaneously into 16-bit samples and wirelessly transfer them to base module using Bluetooth technology. In base module, the samples are combined using time division multiplexing into composite stream and serially forwarded to the host computer. The string buffer is implemented in the sensor module firmware to increase the transfer time, transfer samples in chunks and eliminate the wireless transmission latency. The wireless network is established between modules. The newly implemented firmware results in...
A current Re-use quadrature RF receiver front-end for low power applications: blixator circuit
, Article IEEE Journal of Solid-State Circuits ; Volume 57, Issue 9 , 2022 , Pages 2672-2684 ; 00189200 (ISSN) ; Ghafari, A ; Meghdadi, M ; Medi, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This article presents the theory and implementation of a quadrature and differential RF front-end receiver. Combining balun, low-noise amplifier (LNA), mixer, and oscillator in a single stage, the proposed circuit, named the Blixator, is well suited for low-power applications. The baseband's transimpedance amplifier (TIA) also shares part of its dc current with the Blixator cell, resulting in sub-milliwatt power consumption. To avoid additional power and area by quadrature LO generation, the I/Q signals are generated at RF, employing the inductors already required for providing the dc current path of the LNA transistors. The expressions for gain, noise figure (NF), and phase noise of the...
Design of Low Spur Fast Settling Integer-N Frequency Synthesizer for Bluetooth Application
, M.Sc. Thesis Sharif University of Technology ; Safarian, Amin Ghasem (Supervisor) ; Atarodi, Mojtaba (Supervisor)
Abstract
Frequency synthesizers are one of the most critical building blocks of RF systems. Their task is to produce high-frequency precise and stable clock signals from a low-frequency source. The signal used in mixers to up-convert and down-convert desired signals in transceivers and the precise clock of analog to digital converters are made by frequency synthesizers. Designing frequency synthesizer, because of its lots of parameter and dependency of these parameters to each other, is a hard task which forces designers to propose new structures. In this thesis, an integer-N frequency synthesizer for Bluetooth application, with the goals of decreasing spurious tones power and settling time, is...
Design of Ultra Low Power RF Front-End Based on Current Reuse for Bluetooth Low Energy Standard
, M.Sc. Thesis Sharif University of Technology ; Safarian, Aminghasem (Supervisor) ; Atarodi, Mojtaba (Co-Supervisor)
Abstract
Bluetooth low energy, originally developed by Nokia as wibree, was formally introduced by SIG group in 2010. It is a promising technology for internet of things (IoT) which needs ultra low power consumption. Unlike digital circuits that the power consumption decreases with technology scaling and consequently decreasing the supply voltage, the scaling has not such effect in analog circuits for two reasons. First, the power consumption of an analog circuit is mainly determined by its noise and linearity specification which in almost all cases is determined by the standard. Second, due to noise consideration, analog designers prefer to not to use the latest technology for example because of...
Design of a Low-power Receiver in Bluetooth Low-energy Standard
, M.Sc. Thesis Sharif University of Technology ; Fotowat Ahmady, Ali (Supervisor)
Abstract
One of the most important parameters of a smartphone is the ability to operate in a long time with a rechargeable battery. As a result, the design of radio frequency circuits which are used in these cell phones is a consistent challenge for designers. Bluetooth Low-Energy standard (BLE) which is the fourth edition of Bluetooth standard is recently introduced with the aim of transporting low volume data with minimum power consumption. The most important challenge of the design of an RF receiver in the BLE standard is the power consumption. In a typical receiver, the oscillator and the mixer are the most power hungry blocks. Therefore, decreasing the power consumption of these two blocks is...
Analyzing the Energy Consumption of Error Control Mechanisms in Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Beigy, Hamid (Supervisor)
Abstract
Nowadays wireless technology is widespread all over the world, because of extensive and successful application of low cost, low power, multifunctional tiny sensor nodes that can be grouped to make up of a wireless sensor network (WSN). Some of Wireless sensor network technologies include Zigbee, EnOcean, Personal area network, Ultra-Wideband and Bluetooth which this thesis focuses on the last one. Scalability, mobility, reliability and energy efficiency are some of the requirements and challenges of WSNs, which among them reliability and reducing energy consumption are two important objectives in wireless sensor networks. Since each sensor node has limited energy to consume, overcoming the...
Indoor Positioning Based on Wi-Fi and Bluetooth Low Energy
, M.Sc. Thesis Sharif University of Technology ; Shah Mansouri, Hamed (Supervisor)
Abstract
Indoor positioning plays a pivotal role in a wide range of applications, from smart homes to industrial automation. In this thesis, we propose a comprehensive approach for accurate positioning in indoor environments through the integration of existing Wi-Fi and Bluetooth Low Energy (BLE) devices. The proposed algorithm involves acquiring the received signal strength indicator (RSSI) data from these devices and capturing the complex interactions between RSSI and positions. To enhance the accuracy of the collected data, we first use a Kalman filter for denoising RSSI values, then categorize them into distinct classes using the K-nearest neighbor (KNN) algorithm. Incorporating the filtered...
Reliability/energy trade-off in Bluetooth error control schemes
, Article Microelectronics Reliability ; Volume 51, Issue 8 , August , 2011 , Pages 1398-1412 ; 00262714 (ISSN) ; Jalali, F ; Ejlali, A ; Sharif University of Technology
2011
Abstract
Two important objectives in wireless sensor networks are reliability and reducing energy consumption. Hence, overcoming energy constraints and utilizing error control schemes such as Automatic Repeat Request (ARQ) and Forward Error Correction (FEC) are necessary to improve the energy efficiency and reliability. However, these two concerns are at odds, so there is a trade-off between them. Considering this point, the impact of various error control schemes on these objectives and the trade-off between them has been considered in Bluetooth networks recently. However, all these works consider ideal assumptions (e.g., perfect error detection) only. This work evaluates the energy-efficiency of...
Mobile banking services in the bank area
, Article SICE Annual Conference, SICE 2007, Takamatsu, 17 September 2007 through 20 September 2007 ; 2007 , Pages 2682-2685 ; 4907764286 (ISBN); 9784907764289 (ISBN) ; Shirali Shahreza, M. H ; Sharif University of Technology
2007
Abstract
Mobile banking (M-Banking) has been welcomed in most of the countries as a new branch in electronic banking (E-Banking). In developing countries such as Iran mobile banking is limited to fields such as SMS due to lack of infrastructure and because of high costs. In this paper we present a method for developing banking services through mobile phone in the bank area. In our method a server which is capable to be connected through bluetooth is installed in the bank and offered banking services. Customers inside the bank and also around the bank are connected to the bank system through bluetooth technology and handle their banking operations through their mobile phones. This way they won't pay...
Estimation of Rout & Link Traffic Volume in Transportation Networks using Bluetooth & Wi-Fi Source Data
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
Route information and link traffic volume are among the most important means that are used for analyzing transportation networks. In the past, data from Traffic Counters and Automatic Number Plate Recognition were common ways for estimating route volumes. However, the estimation of these information has improved significantly and can be done cheaper with the development of new technologies and emergence of powerful tools. One of the cheapest and highly available tools is the use of wireless networks. The most popular of such these networks are Bluetooth and Wi-Fi technologies. The use of data generated from these technologies in engineering sciences has increased due to the popularity of...
TDC & MMD Design for Bluetooth Low Energy Standard Transmitter
, M.Sc. Thesis Sharif University of Technology ; Fotowwat Ahmadi, Ali (Supervisor)
Abstract
IoE devices are going to integrate with our environment. It has been predicted that there would be more than 6 connected devices per each person by 2020. Currently what obstruct this technology from continuing its evolusion path, is its dependence on Ultra Low-Power devices, and for this reason there is a huge concenteration on Radio-Frequency standards which can make devices more power efficient. Within these standards, Bluetooth Low Energy (BLE) attracted designers consentration for its similarities with conventional Bluetooth and its dominance in cellphones and other portable devices.In this project, we have attempted to design a trasmitter for BLE standard based on an All Digital Phase...
Design of RF Receiver Front-End for Low Power Applications
, Ph.D. Dissertation Sharif University of Technology ; Medi, Ali (Supervisor) ; Meghdadi, Masoud (Co-Supervisor)
Abstract
The quest for reducing power consumption, external components and chip area in integrated circuits is never ended. One of the solutions is to use circuit re-use techniques whereas most of the blocks have multi tasks in the architecture. Besides that, the bias current is shared between the various parts of the system. Consequently, the total power and chip area are reduced. This thesis introduces Blixator (Balun, LNA, Mixer and Oscillator) circuit as a new generation of circuit and current re-use topologies for low power applications. The receiver has been designed for BLE applications. It exhibits a NF of 10.5 dB, IIP3 of -15.5 dBm, IRR of 23 dB, input impedance matching of -15 dB in 80 MHz...