Current Issue : January - March Volume : 2014 Issue Number : 1 Articles : 4 Articles
Force and tactile sensors are basic elements for robot perception and control, which call for large range and high-accuracy amplifier.\r\nIn this paper, a novel A/D conversion circuit for array tactile sensor is proposed by using nonlinear tent map phenomenon, which\r\nis characterized by sensitivity to small signal and nonlinear amplifying function. The tent map based A/D conversion circuits can\r\nsimultaneously realize amplifying and A/D converting functions. The proposed circuit is not only simple but also easy to integrate\r\nand produce. It is very suited formultipath signal parallel sampling and A/D converting of large array tactile sensor....
Over the past decade, wireless sensor network research primarily relied on\r\nhighly-integrated commercial off-the-shelf radio chips. The rigid silicon implementation\r\nof the radio stack restricted access to the lower layers; thus, research focused mainly\r\non the medium access control (MAC) layer and above. SRAM field-programmable\r\ngate array (FPGA)-based software-defined radios (SDR), on the other hand, provide a\r\nflexible architecture to experiment with any and all layers of the radio stack, but usually\r\nrequire desktop computers and draw high currents that prohibit mobile or longer-term\r\noutdoor deployments. To address these issues, we have developed a modular flash\r\nFPGA-based wireless research platform, called Marmote SDR, that has computational\r\nresources comparable to those of SRAM FPGA-based radio platforms, but at a reduced\r\npower consumption, with duty cycling support. We discuss the design decisions underlying\r\nMarmote SDR and evaluate its power consumption. Furthermore, we present and evaluate\r\nan asynchronous and multiple access communication protocol specifically designed for\r\ndata-gathering wireless sensor networks....
Bluetooth Low Energy (BLE) is a recently developed energy-efficient short-range\r\nwireless communication protocol. In this paper, we discuss and compare the maximum\r\npeer-to-peer throughput, the minimum frame turnaround time, and the energy consumption\r\nfor three protocols, namely BLE, IEEE 802.15.4 and SimpliciTI. The specifics and the\r\nmain contributions are the results both of the theoretical analysis and of the empirical\r\nmeasurements, which were executed using the commercially available hardware\r\ntransceivers and software stacks. The presented results reveal the protocols� capabilities\r\nand enable one to estimate the feasibility of using these technologies for particular\r\napplications. Based on the presented results, we draw conclusions regarding the feasibility\r\nand the most suitable application scenarios of the BLE technology....
This paper presents the theoretical analysis, simulation results and suggests\r\ndesign in digital technology of a physical layer for wireless sensor networks. The proposed\r\ndesign is able to mitigate fading inside communication channel. To mitigate fading the\r\nchip interleaving technique is proposed. For the proposed theoretical model of physical\r\nlayer, a rigorous mathematical analysis is conducted, where all signals are presented and\r\nprocessed in discrete time domain form which is suitable for further direct processing\r\nnecessary for devices design in digital technology. Three different channels are used to\r\ninvestigate characteristics of the physical layer: additive white Gaussian noise channel\r\n(AWGN), AWG noise and flat fading channel and AWG noise and flat fading channel with\r\ninterleaver and deinterleaver blocks in the receiver and transmitter respectively. Firstly, the\r\nmathematical model of communication system representing physical layer is developed\r\nbased on the discrete time domain signal representation and processing. In the existing\r\ntheory, these signals and their processing are represented in continuous time form, which is\r\nnot suitable for direct implementation in digital technology. Secondly, the expressions for\r\nthe probability of chip, symbol and bit error are derived. Thirdly, the communication\r\nsystem simulators are developed in MATLAB. The simulation results confirmed\r\ntheoretical findings....
Loading....