Distance Estimation Algorithm for Wireless Localization Systems Based on Lyapunov Sensitivity Theory

The paper describes a novel distance evaluation algorithm based on the time-difference of arrival (TDOA) principle. The proposed method solves the distance estimation problem applying the Lyapunov theory. To perform this task, the distance evaluation problem is converted to a parameters identification process exploiting the sensing signal peculiarities. This latter combines the properties of the Frank-Zadoff-Chu (FZC) sequences with the Orthogonal Frequency-Division Multiplexing (OFDM) modulation scheme. The resulting signal can be used to improve accuracy and precision in distance estimation using a reduced signal bandwidth. The system was modeled considering either an additive white noise Gaussian channel and a moderate multipath model. The simulation results demonstrate that the system achieves an accuracy and a precision better than 10 cm considering SNR equal to 0 dB and signal bandwidths of only 125 MHz

A Modulator-less Beam Steering Transmitter based on a revised DDS-PLL Phase Shifter Architecture

This paper details the design and implementation of a modulator-less beam steering transmitter based on a revised DDS-PLL phase shifter architecture. The proposed topology targets low data rate communications for Internet-of-Things systems, and has been demonstrated using an FPGA evaluation board and a custom PCB with four PLLs centered at 2.453-GHz. Measured system performance for an experimental 32-kbps data rate achieved through a 16-PSK modulation scheme are discussed. The proposed architecture is frequency independent, can be used in multi-band devices and has the potential for being integrated as an RF System-on-Chip

A Modulator-less Beam Steering Transmitter based on a revised DDS-PLL Phase Shifter Architecture

This paper details the design and implementation of a modulator-less beam steering transmitter based on a revised DDS-PLL phase shifter architecture. The proposed topology targets low data rate communications for Internet-of-Things systems, and has been demonstrated using an FPGA evaluation board and a custom PCB with four PLLs centered at 2.453-GHz. Measured system performance for an experimental 32-kbps data rate achieved through a 16-PSK modulation scheme are discussed. The proposed architecture is frequency independent, can be used in multi-band devices and has the potential for being integrated as an RF System-on-Chip

Combination of the Systemin peptide with the beneficial fungus Trichoderma afroharzianum T22 improves plant defense responses against pests and diseases

Trichoderma spp. are among the most widely used plant beneficial fungi in agriculture. Its interaction with the plant triggers resistance responses by the activation of Induced Systemic Resistance mediated by Jasmonic acid and Ethylene and/or Systemic Acquired Resistance, which involves Salicylic acid, with the consequent control of a wide range of plant parasites. However, the benefit they can confer to plants may be reduced or nullified by environmental conditions or fungal ecological fitness. A novel approach to enhance their effectiveness in plant defense is to combine them with bioactive molecules including plant-derived compounds. Here, we show that plant treatment with Trichoderma afroharzianum (strain T22) and Systemin, a tomato peptide active in triggering plant defense, confers protection against the fungal pathogens Fusarium oxysporum, Botrytis cinerea and the insect pest Tuta absoluta. The observed defensive response was associated with an increase of Jasmonic acid and related metabolites and a decrease of Salicili acid

Innovative Strategy for Mixer Design Optimization Based on gm/ID Methodology

This work introduces a process to optimize the design of a down-conversion mixer using an innovative strategy based on the gm/ID methodology. The proposed process relies on a set of technology-oriented lookup tables to optimize the trade-off between gain, power dissipation, noise, and distortion. The design is implemented using a 0.13 μm CMOS technology, and to the best of our knowledge, it possesses the best (post-layout simulation) figure of merit (FOM) among the works presented in literature. The FOM is defined as the product of gain and third-order intercept divided the product between average noise figure and power dissipation. Finally, the core of the mixer takes only 31 µm by 28 µm and it draws a current of 1 mA from the 1.5 V DC supply

A Linear Technique for Artifacts Correction and Compensation in Phase Interferometric Angle of Arrival Estimation

Radio localization and radio positioning are relevant research fields for many telecommunications technologies. Usually, the solutions proposed by the literature rely on adaptive techniques related to some parameters that can be extracted from the received signal in cooperative device tracking. In this paper, we explore the artifacts that may be introduced into Angle-of-Arrival estimation based on phase interferometry, and we introduce a simple technique to mitigate their impact. Details of the mathematical discussion are presented and the approach is experimentally validated. The experimental results are compared with raw data to demonstrate the effectiveness of the proposed technique