The Naval Air Warfare Center Weapons Division requires two modules to measure electromagnetic emissions at GPS frequencies L1 and L2. The project team designed rugged field modules that measure power from -80 dBm to 30 dBm with 1 dB resolution. Each module outputs data through an RS-232 port at over 10 samples per second. The open architecture allows components to be modified for different frequencies. The team delivered the modules on time and under budget.
This document is a final report for the Advanced Radio Transmission Experimental Michigan Satellite (ARTEMIS) project. It provides an overview of the mission requirements and design drivers for the subsystems of the ARTEMIS CubeSat. The report describes the preliminary analyses and simulation tools used to evaluate the performance of the satellite's orbits, communication system, propulsion system, electrical power system, attitude determination and control system, command and data handling system, structures, thermal control system, and guidance system.
eSA’s Optical High-Resolution Mission for GMeS Operational ServicesCláudio Carneiro
- Sentinel-2 is a European Space Agency (ESA) satellite mission that will provide high-resolution optical imagery for land monitoring as part of the Global Monitoring for Environment and Security (GMES) program.
- It consists of two satellites that will fly in the same orbit 180 degrees apart to provide global coverage every 5 days. The first satellite, Sentinel-2A, is scheduled to launch in late 2013.
- Each satellite carries a MultiSpectral Instrument (MSI) that images the Earth's surface in 13 spectral bands with spatial resolutions ranging from 10-60 meters to monitor land, emergency response, and security services.
Evaluation of tdoa techniques for positionChau Tran
This thesis analyzes the performance of Time Difference of Arrival (TDOA) techniques for position location in Code Division Multiple Access (CDMA) systems. It compares different algorithms for estimating TDOAs and solving the resulting hyperbolic equations. It also evaluates TDOA accuracy under various conditions like noise, interference, fading and base station configuration. The thesis proposes an improved method for TDOA estimation in CDMA that provides greatly enhanced performance even in poor conditions.
This document describes experiments conducted to commission a Radiation Measurement Device (RMD) RadCam for use at the University of Ontario Institute of Technology. The experiments included: 1) A six-point energy calibration using various radioactive sources to generate a calibration curve; 2) Nuclear and video image alignment using a Cesium-137 source to ensure images were centered; 3) A spatial resolution experiment using two Cesium-137 sources to determine the minimum source separation the device could distinguish. The calibration curve allowed converting channel numbers in spectra to energy values. Alignment positioned the detector for accurate imaging. The spatial resolution experiment established the device's ability to locate sources near each other.
Implementation of a Localization System for Sensor Networks-berkleyFarhad Gholami
This dissertation discusses the implementation of a localization system for sensor networks. It addresses two main tasks: establishing relationships to reference points (e.g. distance measurements) and using those relationships and reference point positions to calculate sensor positions algorithmically.
The dissertation first presents various centralized and distributed localization algorithms from existing research. It then focuses on implementing a distributed, least-squares-based localization algorithm and designing an ultra-low power hardware architecture for it. Measurement errors due to fixed-point arithmetic are also analyzed.
The second part of the dissertation proposes, designs and prototypes an RF signal-based time-of-flight ranging system. The prototype achieves a measurement error within -0.5m to 2m at 100
Microstrip Antenna Resonating at Ku-band frequency Reportcharan -
The document describes the design and simulation of a rectangular microstrip patch antenna operating at 15GHz (Ku-band) frequency. A rectangular microstrip patch antenna was designed using HFSS software to resonate at 15GHz. The antenna's bandwidth, radiation pattern and return loss were determined using simulation. Microstrip patch antennas are commonly used for space applications due to their low profile, lightweight and conformability to planar and non-planar surfaces. They consist of a metallic patch on a grounded dielectric substrate. The designed antenna will operate in the Ku-band commonly used for space communications, radar and other applications.
End of Semester Design Report Final VersionDaniel Worts
This document presents a proposal for an autonomous quadcopter senior design project. The goal is to design and build a quadcopter capable of GPS waypoint navigation with multiple flight modes and safety features. Key specifications include a 15 minute maximum flight time, 0.75 mile video transmission range, object avoidance sensors, and a parachute system for failures. The design process will focus on a durable yet lightweight frame and reducing vibrations to ensure smooth video and avoid interfering with electronics. By spring, the team aims to have a functional quadcopter with altitude control via manual controller and autonomous software, while transmitting video.
This project report summarizes work done on the design, simulation and fabrication of various antennas. A group focused on fabricating a slotted waveguide omni directional antenna and a biquad directional antenna. Another group designed and simulated patch antennas using software, optimizing a 1.9GHz rectangular probe fed patch antenna. They also simulated a dual band patch antenna and a microstrip fed patch antenna. The report covers antenna parameters, hardware fabrication and testing, as well as software simulation methods.
This document is a final report for the Advanced Radio Transmission Experimental Michigan Satellite (ARTEMIS) project. It provides an overview of the mission requirements and design drivers for the subsystems of the ARTEMIS CubeSat. The report describes the preliminary analyses and simulation tools used to evaluate the performance of the satellite's orbits, communication system, propulsion system, electrical power system, attitude determination and control system, command and data handling system, structures, thermal control system, and guidance system.
eSA’s Optical High-Resolution Mission for GMeS Operational ServicesCláudio Carneiro
- Sentinel-2 is a European Space Agency (ESA) satellite mission that will provide high-resolution optical imagery for land monitoring as part of the Global Monitoring for Environment and Security (GMES) program.
- It consists of two satellites that will fly in the same orbit 180 degrees apart to provide global coverage every 5 days. The first satellite, Sentinel-2A, is scheduled to launch in late 2013.
- Each satellite carries a MultiSpectral Instrument (MSI) that images the Earth's surface in 13 spectral bands with spatial resolutions ranging from 10-60 meters to monitor land, emergency response, and security services.
Evaluation of tdoa techniques for positionChau Tran
This thesis analyzes the performance of Time Difference of Arrival (TDOA) techniques for position location in Code Division Multiple Access (CDMA) systems. It compares different algorithms for estimating TDOAs and solving the resulting hyperbolic equations. It also evaluates TDOA accuracy under various conditions like noise, interference, fading and base station configuration. The thesis proposes an improved method for TDOA estimation in CDMA that provides greatly enhanced performance even in poor conditions.
This document describes experiments conducted to commission a Radiation Measurement Device (RMD) RadCam for use at the University of Ontario Institute of Technology. The experiments included: 1) A six-point energy calibration using various radioactive sources to generate a calibration curve; 2) Nuclear and video image alignment using a Cesium-137 source to ensure images were centered; 3) A spatial resolution experiment using two Cesium-137 sources to determine the minimum source separation the device could distinguish. The calibration curve allowed converting channel numbers in spectra to energy values. Alignment positioned the detector for accurate imaging. The spatial resolution experiment established the device's ability to locate sources near each other.
Implementation of a Localization System for Sensor Networks-berkleyFarhad Gholami
This dissertation discusses the implementation of a localization system for sensor networks. It addresses two main tasks: establishing relationships to reference points (e.g. distance measurements) and using those relationships and reference point positions to calculate sensor positions algorithmically.
The dissertation first presents various centralized and distributed localization algorithms from existing research. It then focuses on implementing a distributed, least-squares-based localization algorithm and designing an ultra-low power hardware architecture for it. Measurement errors due to fixed-point arithmetic are also analyzed.
The second part of the dissertation proposes, designs and prototypes an RF signal-based time-of-flight ranging system. The prototype achieves a measurement error within -0.5m to 2m at 100
Microstrip Antenna Resonating at Ku-band frequency Reportcharan -
The document describes the design and simulation of a rectangular microstrip patch antenna operating at 15GHz (Ku-band) frequency. A rectangular microstrip patch antenna was designed using HFSS software to resonate at 15GHz. The antenna's bandwidth, radiation pattern and return loss were determined using simulation. Microstrip patch antennas are commonly used for space applications due to their low profile, lightweight and conformability to planar and non-planar surfaces. They consist of a metallic patch on a grounded dielectric substrate. The designed antenna will operate in the Ku-band commonly used for space communications, radar and other applications.
End of Semester Design Report Final VersionDaniel Worts
This document presents a proposal for an autonomous quadcopter senior design project. The goal is to design and build a quadcopter capable of GPS waypoint navigation with multiple flight modes and safety features. Key specifications include a 15 minute maximum flight time, 0.75 mile video transmission range, object avoidance sensors, and a parachute system for failures. The design process will focus on a durable yet lightweight frame and reducing vibrations to ensure smooth video and avoid interfering with electronics. By spring, the team aims to have a functional quadcopter with altitude control via manual controller and autonomous software, while transmitting video.
This project report summarizes work done on the design, simulation and fabrication of various antennas. A group focused on fabricating a slotted waveguide omni directional antenna and a biquad directional antenna. Another group designed and simulated patch antennas using software, optimizing a 1.9GHz rectangular probe fed patch antenna. They also simulated a dual band patch antenna and a microstrip fed patch antenna. The report covers antenna parameters, hardware fabrication and testing, as well as software simulation methods.
Vijayananda Mohire led a project to design a digital energy meter to address limitations in electro-mechanical meters. The project involved analyzing electro-mechanical meters, designing hardware modules for voltage, current and power factor processing, developing software using assembly language, and testing the working prototype. Mohire guided the team through technical and implementation challenges to successfully complete and demonstrate the project.
From nwokolo eric onyekachi(mini project 492)Eric Brendan
The document discusses applications of high temperature superconductors in power system transmission and their benefits. It provides an overview of superconductor materials and their special properties. Some key applications of HTS cables discussed are increasing transmission capacity without raising system voltages. HTS cables have much higher power density than copper cables and can be installed more compactly. They also have virtually zero resistance and can help stabilize power flows. Overall, the document examines how HTS technology can help address issues with aging power grid infrastructure and increasing demand.
Tec test procedure em fields from bts antennae 3Shiv Chaudhary
This document provides guidelines for measuring electromagnetic fields from base station antennas to ensure compliance with exposure limits set by the Department of Telecommunications in India. It outlines procedures for self-certification by service providers and auditing by the Telecom Enforcement Resource and Monitoring cell. Measurement methods include calculations based on technical parameters, software simulation, and on-site testing using broadband and frequency-selective instruments. Compliance distances and safety signage requirements are also specified. The goal is to confirm base station installations meet prescribed limits for public exposure to electromagnetic fields.
- The document is a master's thesis report that evaluates the impact on ampacity (current carrying capacity) of power cables according to IEC-60287 when cables are placed in thermally unfavorable conditions.
- The report compares a conventional technique of placing cables in cable trenches to a method of placing cables in protective plastic ducts. Comparisons are made regarding ampacity, cost, and technical simplifications.
- Based on the analysis using IEC-60287 models, the results show that placing cables in plastic ducts provides sufficient ampacity for the given circumstances while allowing more flexibility in cable placement logistics compared to cable trenches.
This dissertation proposes using neural networks and field programmable gate arrays to control reconfigurable antennas. A new approach is presented to model reconfigurable antennas using neural networks trained in Matlab. The neural network model is then implemented on an FPGA board using Xilinx System Generator blocks. With the neural network embedded on the FPGA board, it acts as a real-time controller for the reconfigurable antenna to optimize its configuration based on the antenna behavior it has learned. Several examples of reconfigurable antenna modeling and FPGA-based neural network control are provided to demonstrate the approach.
This document presents the design and testing of several prototypes for a switching power amplifier intended to drive piezoelectric transducers. The initial through-hole prototype achieved the power and frequency specifications but had low efficiency. Revision 2 improved efficiency but failed due to heat issues. Revision 3 addressed this with a thermally enhanced design, achieving the highest efficiency. An isolated gate driver was also developed to allow testing higher voltages safely. Overall the work progressed from non-isolated to isolated amplifier designs with improvements in efficiency, voltage handling, and reliability at each stage.
This master's thesis develops a mathematical index called the Γ-index to quantify the technological flexibility of dispatchable power generation units. The Γ-index is calculated as the normalized integral of weighted flexibility terms over time. These terms evaluate dynamic features like ramp rates and minimum run times, as well as static features such as maximum step changes and reliability. The Γ-index is tested by evaluating the flexibility of different power plant technologies. The results show diesel engines and gas turbines are most flexible, followed by combined cycle plants, then steam plants, with nuclear ranked as least flexible. The Γ-index could help quantify the value of flexible generation and inform decisions around power system planning and policymaking.
This document is a dissertation submitted by Saurabh Kumar Panda for the degree of Master of Technology. It presents a project to establish a firmware over-the-air deployment system for a wireless sensor network. The project aims to enable wireless firmware updates for an existing embedded wireless sensor network. It discusses developing firmware for router and target nodes, and a user interface, to allow firmware updates to be sent over-the-air from the router to physically disconnected target nodes. Testing was done on a real system with two nodes communicating wirelessly. The work establishes a proof-of-concept system for remote firmware updates in a wireless network using the developed firmware and radio driver.
A study on improving speaker diarization system = Nghiên cứu phương pháp cải ...Man_Ebook
The document is a master's thesis that explores improving a speaker diarization system by comparing X-Vectors and ECAPA-TDNN embeddings. It includes:
- An introduction outlining the research interest in evaluating these two embedding methods on Vietnamese data sets for speaker verification and diarization tasks.
- Details of the baseline system that uses X-Vector embeddings and the proposed system that replaces it with ECAPA-TDNN embeddings.
- Experiments conducted on private (IPCC_110000, VTR_1350) and public (ZALO_400) data sets to evaluate the systems, along with results showing the proposed system outperforms the baseline.
A study on improving speaker diarization system = Nghiên cứu phương pháp cải ...Man_Ebook
The document is a master's thesis submitted by Tung Lam Nguyen to the Hanoi University of Science and Technology. It studies improving speaker diarization systems by exploring the capabilities of ECAPA-TDNN embeddings versus X-Vector embeddings in a Vietnamese speaker diarization system. The thesis contains experiments evaluating both baseline and proposed systems on speaker verification and speaker diarization tasks using various private and public Vietnamese datasets. The results show that the proposed system using ECAPA-TDNN outperforms the baseline X-Vector system on all tasks and datasets.
This dissertation examines modeling considerations for long-term generation and transmission expansion planning to address increasing load uncertainty and renewable generation. The author develops an optimization framework using an outer optimization to search for candidate upgrades and an inner optimization to evaluate cost and reliability. Simulations are performed on the IEEE 14 bus system comparing a unified generation and transmission expansion planning model to a sequential one. Sensitivity analyses evaluate the impact of perturbations and load uncertainty on system cost and reliability. The results provide insights into planning with high renewable penetration under uncertainty.
Lessons Learned in ICFMP Project for Verification and Validation of Computer ...Dr. Monideep Dey
This report presents a synthesis of the technical and programmatic “lessons learned” in the International collaborative Fire Model Project (ICFMP) that was conducted from 1999 to 2008. A synthesis of ICFMP results has been conducted as a project of Deytec, Inc. to benefit public safety and the scientific community. The verification and validation
(V&V) process in the ICFMP project was developed to examine the capabilities and limitations of fire models for nuclear plant fire safety and risk analysis, and to determine the predictive errors of the models. Although current models can reliably predict global parameters in nuclear plant compartment fires such as hot gas temperature and interface height, they are limited and need to be improved for predicting important parameters like the heat flux to cable targets. The development of V&V process provided experience in the conduct of blind exercises; however, it was not possible to determine the true
predictive errors of the models due to issues related to model input data and procedures for blind exercises. These issues could be addressed and the V&V process can be improved. The experience in the ICFMP has formed the basis of a V&V process for the evaluation of fire models for nuclear plant applications.
The document describes an Echo State Fitted-Q Iteration (ESFQ) algorithm to learn control systems with delays. ESFQ is a batch reinforcement learning method that uses echo state networks for function approximation to estimate Q-values while preserving the Markov property by holding state histories. Experimental results on simulated benchmarks show ESFQ improves performance over standard tapped delay-line algorithms and that nonlinear readout layers help learn complex dynamics better than linear layers. The goal is to develop an effective and efficient reinforcement learning approach for learning delayed control systems without knowing their dynamics.
- The document proposes analytical models to estimate electromagnetic field (EMF) emissions from Wi-Fi and powerline communication (PLC) links in a home network.
- It develops a model for Wi-Fi EMF emissions based on assumptions about the transmission system, propagation environment, and a path loss model. This is used to define a "radiant exposure" (RE) routing metric that estimates the expected radiated energy within a radiation-sensitive area from transmitting along a path.
- The RE metric incorporates the effects of distance between the radiating sources and sensitive area, as well as the asymmetry of radiated energy regarding the direction of each link. It is designed to fit within shortest path routing algorithms to find minimum
This document is the final thesis report submitted by four students for their Bachelor's degree in Computer and Electrical Engineering. It documents their design project titled "Demand Side Load Management to Match Solar Power Generation". The project aims to manage household loads by prioritizing them and turning off less important loads when solar power generation drops, in order to match supply and demand. It uses an Arduino microcontroller connected to sensors to monitor battery voltage and current, and control relays that switch loads on and off. The report describes the design, components, calculations, code, and implementation of the system to automatically manage household loads powered by a solar generator during periods of low solar power generation.
This document describes the design of a real-time standalone system for controlling load resonant inverters using a TMS320F28335 digital signal processor (DSP). It discusses implementing a digital control algorithm optimized in embedded C language. The algorithm is experimentally evaluated on a load resonant inverter prototype for an induction heating system. Sections cover literature review on induction heating and switched mode power supplies, the control algorithm mathematical model and software model, implementation details including hardware/software components and experimental setups, simulation and real-time results, and conclusions.
The document provides an overview of engineering prints and drawings, including:
- The typical components of drawings such as the title block, grid system, and revision block.
- The main categories of drawings like piping and instrumentation diagrams, electrical schematics, and fabrication drawings.
- Views and perspectives commonly used in drawings such as orthographic, isometric, and exploded views.
This document describes the EnerScope energy management system project. The system aims to integrate various hardware devices and communication interfaces on a common platform. It acquires electricity usage and environmental data from loads like the Experimental Power Grid Centre and a smart home testbed. Data is collected using devices like data acquisition modules, an intelligent energy meter, and wireless sensor motes. These devices communicate through serial, WiFi, and local area network protocols. LabVIEW software is used to retrieve and process the data, which is stored in a database. The system demonstrates real-time energy monitoring and demand response capabilities.
This document is a project report on an Eye Tracking Interpretation System submitted by three students as a partial fulfillment of their Bachelor of Electronics and Telecommunication Engineering degree. It includes sections on introduction, literature survey, system description, software description, methodology, results, applications, and conclusion. The system uses an ultrasonic sensor and microcontroller to measure the distance to obstacles and displays it on an LCD screen. It aims to provide a low-cost solution for distance measurement that works in different light conditions including underwater.
Vijayananda Mohire led a project to design a digital energy meter to address limitations in electro-mechanical meters. The project involved analyzing electro-mechanical meters, designing hardware modules for voltage, current and power factor processing, developing software using assembly language, and testing the working prototype. Mohire guided the team through technical and implementation challenges to successfully complete and demonstrate the project.
From nwokolo eric onyekachi(mini project 492)Eric Brendan
The document discusses applications of high temperature superconductors in power system transmission and their benefits. It provides an overview of superconductor materials and their special properties. Some key applications of HTS cables discussed are increasing transmission capacity without raising system voltages. HTS cables have much higher power density than copper cables and can be installed more compactly. They also have virtually zero resistance and can help stabilize power flows. Overall, the document examines how HTS technology can help address issues with aging power grid infrastructure and increasing demand.
Tec test procedure em fields from bts antennae 3Shiv Chaudhary
This document provides guidelines for measuring electromagnetic fields from base station antennas to ensure compliance with exposure limits set by the Department of Telecommunications in India. It outlines procedures for self-certification by service providers and auditing by the Telecom Enforcement Resource and Monitoring cell. Measurement methods include calculations based on technical parameters, software simulation, and on-site testing using broadband and frequency-selective instruments. Compliance distances and safety signage requirements are also specified. The goal is to confirm base station installations meet prescribed limits for public exposure to electromagnetic fields.
- The document is a master's thesis report that evaluates the impact on ampacity (current carrying capacity) of power cables according to IEC-60287 when cables are placed in thermally unfavorable conditions.
- The report compares a conventional technique of placing cables in cable trenches to a method of placing cables in protective plastic ducts. Comparisons are made regarding ampacity, cost, and technical simplifications.
- Based on the analysis using IEC-60287 models, the results show that placing cables in plastic ducts provides sufficient ampacity for the given circumstances while allowing more flexibility in cable placement logistics compared to cable trenches.
This dissertation proposes using neural networks and field programmable gate arrays to control reconfigurable antennas. A new approach is presented to model reconfigurable antennas using neural networks trained in Matlab. The neural network model is then implemented on an FPGA board using Xilinx System Generator blocks. With the neural network embedded on the FPGA board, it acts as a real-time controller for the reconfigurable antenna to optimize its configuration based on the antenna behavior it has learned. Several examples of reconfigurable antenna modeling and FPGA-based neural network control are provided to demonstrate the approach.
This document presents the design and testing of several prototypes for a switching power amplifier intended to drive piezoelectric transducers. The initial through-hole prototype achieved the power and frequency specifications but had low efficiency. Revision 2 improved efficiency but failed due to heat issues. Revision 3 addressed this with a thermally enhanced design, achieving the highest efficiency. An isolated gate driver was also developed to allow testing higher voltages safely. Overall the work progressed from non-isolated to isolated amplifier designs with improvements in efficiency, voltage handling, and reliability at each stage.
This master's thesis develops a mathematical index called the Γ-index to quantify the technological flexibility of dispatchable power generation units. The Γ-index is calculated as the normalized integral of weighted flexibility terms over time. These terms evaluate dynamic features like ramp rates and minimum run times, as well as static features such as maximum step changes and reliability. The Γ-index is tested by evaluating the flexibility of different power plant technologies. The results show diesel engines and gas turbines are most flexible, followed by combined cycle plants, then steam plants, with nuclear ranked as least flexible. The Γ-index could help quantify the value of flexible generation and inform decisions around power system planning and policymaking.
This document is a dissertation submitted by Saurabh Kumar Panda for the degree of Master of Technology. It presents a project to establish a firmware over-the-air deployment system for a wireless sensor network. The project aims to enable wireless firmware updates for an existing embedded wireless sensor network. It discusses developing firmware for router and target nodes, and a user interface, to allow firmware updates to be sent over-the-air from the router to physically disconnected target nodes. Testing was done on a real system with two nodes communicating wirelessly. The work establishes a proof-of-concept system for remote firmware updates in a wireless network using the developed firmware and radio driver.
A study on improving speaker diarization system = Nghiên cứu phương pháp cải ...Man_Ebook
The document is a master's thesis that explores improving a speaker diarization system by comparing X-Vectors and ECAPA-TDNN embeddings. It includes:
- An introduction outlining the research interest in evaluating these two embedding methods on Vietnamese data sets for speaker verification and diarization tasks.
- Details of the baseline system that uses X-Vector embeddings and the proposed system that replaces it with ECAPA-TDNN embeddings.
- Experiments conducted on private (IPCC_110000, VTR_1350) and public (ZALO_400) data sets to evaluate the systems, along with results showing the proposed system outperforms the baseline.
A study on improving speaker diarization system = Nghiên cứu phương pháp cải ...Man_Ebook
The document is a master's thesis submitted by Tung Lam Nguyen to the Hanoi University of Science and Technology. It studies improving speaker diarization systems by exploring the capabilities of ECAPA-TDNN embeddings versus X-Vector embeddings in a Vietnamese speaker diarization system. The thesis contains experiments evaluating both baseline and proposed systems on speaker verification and speaker diarization tasks using various private and public Vietnamese datasets. The results show that the proposed system using ECAPA-TDNN outperforms the baseline X-Vector system on all tasks and datasets.
This dissertation examines modeling considerations for long-term generation and transmission expansion planning to address increasing load uncertainty and renewable generation. The author develops an optimization framework using an outer optimization to search for candidate upgrades and an inner optimization to evaluate cost and reliability. Simulations are performed on the IEEE 14 bus system comparing a unified generation and transmission expansion planning model to a sequential one. Sensitivity analyses evaluate the impact of perturbations and load uncertainty on system cost and reliability. The results provide insights into planning with high renewable penetration under uncertainty.
Lessons Learned in ICFMP Project for Verification and Validation of Computer ...Dr. Monideep Dey
This report presents a synthesis of the technical and programmatic “lessons learned” in the International collaborative Fire Model Project (ICFMP) that was conducted from 1999 to 2008. A synthesis of ICFMP results has been conducted as a project of Deytec, Inc. to benefit public safety and the scientific community. The verification and validation
(V&V) process in the ICFMP project was developed to examine the capabilities and limitations of fire models for nuclear plant fire safety and risk analysis, and to determine the predictive errors of the models. Although current models can reliably predict global parameters in nuclear plant compartment fires such as hot gas temperature and interface height, they are limited and need to be improved for predicting important parameters like the heat flux to cable targets. The development of V&V process provided experience in the conduct of blind exercises; however, it was not possible to determine the true
predictive errors of the models due to issues related to model input data and procedures for blind exercises. These issues could be addressed and the V&V process can be improved. The experience in the ICFMP has formed the basis of a V&V process for the evaluation of fire models for nuclear plant applications.
The document describes an Echo State Fitted-Q Iteration (ESFQ) algorithm to learn control systems with delays. ESFQ is a batch reinforcement learning method that uses echo state networks for function approximation to estimate Q-values while preserving the Markov property by holding state histories. Experimental results on simulated benchmarks show ESFQ improves performance over standard tapped delay-line algorithms and that nonlinear readout layers help learn complex dynamics better than linear layers. The goal is to develop an effective and efficient reinforcement learning approach for learning delayed control systems without knowing their dynamics.
- The document proposes analytical models to estimate electromagnetic field (EMF) emissions from Wi-Fi and powerline communication (PLC) links in a home network.
- It develops a model for Wi-Fi EMF emissions based on assumptions about the transmission system, propagation environment, and a path loss model. This is used to define a "radiant exposure" (RE) routing metric that estimates the expected radiated energy within a radiation-sensitive area from transmitting along a path.
- The RE metric incorporates the effects of distance between the radiating sources and sensitive area, as well as the asymmetry of radiated energy regarding the direction of each link. It is designed to fit within shortest path routing algorithms to find minimum
This document is the final thesis report submitted by four students for their Bachelor's degree in Computer and Electrical Engineering. It documents their design project titled "Demand Side Load Management to Match Solar Power Generation". The project aims to manage household loads by prioritizing them and turning off less important loads when solar power generation drops, in order to match supply and demand. It uses an Arduino microcontroller connected to sensors to monitor battery voltage and current, and control relays that switch loads on and off. The report describes the design, components, calculations, code, and implementation of the system to automatically manage household loads powered by a solar generator during periods of low solar power generation.
This document describes the design of a real-time standalone system for controlling load resonant inverters using a TMS320F28335 digital signal processor (DSP). It discusses implementing a digital control algorithm optimized in embedded C language. The algorithm is experimentally evaluated on a load resonant inverter prototype for an induction heating system. Sections cover literature review on induction heating and switched mode power supplies, the control algorithm mathematical model and software model, implementation details including hardware/software components and experimental setups, simulation and real-time results, and conclusions.
The document provides an overview of engineering prints and drawings, including:
- The typical components of drawings such as the title block, grid system, and revision block.
- The main categories of drawings like piping and instrumentation diagrams, electrical schematics, and fabrication drawings.
- Views and perspectives commonly used in drawings such as orthographic, isometric, and exploded views.
This document describes the EnerScope energy management system project. The system aims to integrate various hardware devices and communication interfaces on a common platform. It acquires electricity usage and environmental data from loads like the Experimental Power Grid Centre and a smart home testbed. Data is collected using devices like data acquisition modules, an intelligent energy meter, and wireless sensor motes. These devices communicate through serial, WiFi, and local area network protocols. LabVIEW software is used to retrieve and process the data, which is stored in a database. The system demonstrates real-time energy monitoring and demand response capabilities.
This document is a project report on an Eye Tracking Interpretation System submitted by three students as a partial fulfillment of their Bachelor of Electronics and Telecommunication Engineering degree. It includes sections on introduction, literature survey, system description, software description, methodology, results, applications, and conclusion. The system uses an ultrasonic sensor and microcontroller to measure the distance to obstacles and displays it on an LCD screen. It aims to provide a low-cost solution for distance measurement that works in different light conditions including underwater.
1. EM FIELD MEASUREMENT MODULE FOR EMBEDDED COMPUTING
By:
Lara Cowan
Antonio Jaramillo
Shawn Knapp
David Yazzie
NMT EE Senior Design Team C
Submitted in Partial Fulfillment
of the Requirements for the
Bachelor of Science in Electrical Engineering
New Mexico Institute of Mining and Technology
Department of Electrical Engineering
Socorro, NM
May 4th
, 2005
2. Abstract
The Naval Air Warfare Center Weapons Division (NAWC-WD) often performs
electromagnetic emission test at GPS frequencies that can possibly conflict with regulation levels
imposed by the Department of Defense and other regulatory agencies. NAWC-WD requires a
monitoring system of such emissions to prove or disprove any involvement in any emissions perceived
in the surrounding area.
Current solutions include expensive network analyzers, which require manpower to operate and
are not suitable for fieldwork and survivability. Portable power meters do not provide the required
power ranges, specified communication capabilities, or the ability to be modified to fit other frequency
bands.
The New Mexico Institute of Mining and Technology Senior Design Group C was assigned the
task to design two modules that could measure power at the two GPS frequencies (L1 & L2). Some
important capabilities are that the modules are designed to be easily modified to perform at different
frequencies, being rugged for fieldwork and survivability, powered by both AC and DC, and being able
to communicate with external peripherals for data transfer. Each module corresponds to a frequency
band, L1 or L2, and outputs a digital power value.
EM Field Measurement Module for Embedded Computing 2
3. Acknowledgements
The authors of this document wish to express thanks to the following individuals for their
support throughout the duration of this project.
Dr. Scott Teare, Associate Professor, Department Chair
Dr. Hai Xiao, Faculty Advisor
Ms. Pat Seward, NAWC-WD Sponsor
Mr. James Rogers, NAWC-WD Sponsor
Ms. Melody Rattanapote, NAWC-WD Ordering
Ms. Carrol Teel, EE Department Secretary
Mr. Christopher Ziomek, Ztec Instruments
Mr. Nicholas Tarensenko, NRAO
Mr. Andrew Tubesing, EE Labs Manager
Mr. Norton Euart, R&ED Instrument Lab
EM Field Measurement Module for Embedded Computing 3
4. Table of Contents
Chapter 1: Introduction....................................................................................................................7
Chapter 2: Project Background........................................................................................................9
2.1 Technical Background.............................................................................................. 9
2.2 Specifications.......................................................................................................... 11
2.3 Deliverables.............................................................................................................12
2.4 Project Planning...................................................................................................... 12
2.4.1 Budget..............................................................................................................13
2.4.2 Human Resource Management........................................................................13
Chapter 3: Project Design..............................................................................................................14
3.1 Preliminary Design..................................................................................................14
3.1.1 Cascading Amplifier and Selector...................................................................14
3.1.2 Power Meter.................................................................................................... 16
3.2 Present Design.........................................................................................................17
3.2.1 RF Front End Design.......................................................................................18
3.2.2 Analog and Digital Design..............................................................................19
3.2.3 Software...........................................................................................................21
3.2.4 Enclosure.........................................................................................................22
Chapter 4: Results..........................................................................................................................25
4.1 Subsystem Specifications........................................................................................25
4.2 Reliability................................................................................................................28
4.2.1 Mean Time Between Failures..........................................................................28
4.2.2 Availability......................................................................................................28
4.3 System Specifications............................................................................................. 29
Chapter 6: References....................................................................................................................31
Appendix A: Gantt Chart...............................................................................................................32
Appendix B: Module Housing.......................................................................................................34
Appendix C: PCB.......................................................................................................................... 35
Appendix D: Code.........................................................................................................................36
D.1 Main.c.....................................................................................................................36
D.2 Main.h.................................................................................................................... 44
EM Field Measurement Module for Embedded Computing 4
6. Table of Tables
Table 1: Specifications.............................................................................................................................11
Table 2: Budget........................................................................................................................................13
Table 3: MTBF.........................................................................................................................................28
EM Field Measurement Module for Embedded Computing 6
7. Chapter 1: Introduction
The Naval Air Warfare Center Weapons Division (NAWC-WD) is part of NAVAIR’s
eight sites across the country. The Weapons Division is located at China Lake and Point Mugu
California. NAVAIR works in conjunction with industry to provide support to the operating
armed forces. Some of the products and services include high quality and affordable systems,
aircraft, avionics, air-launched weapons, electronic warfare systems, cruise missiles, unmanned
aerial vehicles, launch and arresting gear, training equipment and facilities.
Throughout the development of products, NAWC-WD often performs electromagnetic
(EM) signal testing in the GPS frequencies that could potentially conflict with regulations from
the Department of Defense, the Federal Aviation Administration, and other government
regulatory agencies. Because there are specific guidelines for EM emissions, it is necessary to
maintain a log to prove or disprove any participation in potentially harmful interference that
could affect military and civilian navigation systems.
There are several devices in the market that could perform the acquisition and recording
of power emissions at the applicable frequencies. Some of the most relevant mechanisms are
network analyzers and portable power meters. However these devices have certain
disadvantages. Network analyzers are very costly, ranging from $5000 to $20,000 each. They are
not portable nor suitable for field operation. The price tag on a network analyzer corresponds to
numerous features unnecessary for the pertinent purpose.
In the other hand, portable power meters are more apt for field operation but do not
support a suitable power range for the purpose. Power meters also have a closed proprietary
architecture, which limits the ability to add or replace components for better resolution, range, or
frequency.
EM Field Measurement Module for Embedded Computing 7
8. The purpose of this project is to develop two modules to measure power emission at the
GPS frequencies. These modules must be rugged for field operation and have an open
architecture to allow customization at different frequencies.
EM Field Measurement Module for Embedded Computing 8
9. Chapter 2: Project Background
2.1 Technical Background
The Global Positioning System (GPS) is a navigation system developed by the United
States Department of Defense (DOD) that provides a precise navigation tool for the military,
which later extended to civilian use. It comprises of a constellation of 24 satellites that orbit the
Earth. GPS uses a system called triangulation to identify a specific location on virtually
anywhere that at least three satellites have direct transmission. GPS satellites transmit in two
bands called L1 and L2. L1 is the most common type used by the civilian community and L2 is
used for higher accuracy, typically for surveys, and military and government applications.
However, receiver antennas are produced in L1 and L1/L2. The operating frequency for L1 is
1575.42 MHz, and for L2 is 1227.6 MHz.
GPS as well as other radio frequency (RF) power is usually measured in dBm. Units of
dBm are decibels relative to 1 mW of power, hence, 0 dBm = 1 mW. The following formula
gives the conversion from dBm to mW,
P(mW) = 10[P(dBm)/10]
and consequentially the conversion to dBm from mW:
P(dBm)=10*log[P(mW)]
The previous equation indicates that dBm is a logarithmic unit, and the power increases by an
order of magnitude for every additional 10 dBm.
The typical power level at which GPS have an acquisition sensitivity of about -130dBm,
which corresponds to about .0001pW. According to DOD specification this value is guaranteed
assuming the receiver has a clear view to the sky. Physical obstacles such as buildings and trees
EM Field Measurement Module for Embedded Computing 9
11. 2.2 Specifications
The following are the required project specifications. The devised modules must measure
the power intensity in both L1 and L2 band frequencies. Each of the two modules will be
assigned a band with a bandwidth of 25 MHz. Each module must be rugged enough to be used in
the field at normal outdoor temperature ranges.
The power to be measured has a range from -80 dBm to 30 dBm. Note that this range is
much greater that the average operation of GPS receivers (-130 to -110 dBm). This range
corresponds to a range in watts from .01nW to 1W.
The modules are to output power data to an external peripheral device through an RS-232
communication port. A data transfer protocol is defined in Chapter 3.3 Software. Because there
is constant communication with an external device internal data storage is not necessary.
The power supply must operate with 120V/60Hz AC or 12V DC input. Ultimately, the
modules can be powered up from a wall outlet or a car battery.
One main feature that the design must provide is open architecture. Implementation of an
open architecture design allows the user to interchange, upgrade, or modify components to adjust
the module to a different specification. For this project, the implementation of open architecture
must concentrate in a different frequencies, but not a different power range.
Antenna Frequencies: 1227.6MHz and 1575.42MHz
Frequency Bandwidth (-3dB): 25MHz
Input Power Range: -80dBm to 30dBm
Measurement Resolution: 1dB
Sampling Rate: >10 Samples/second
External Communication: RS-232 Serial Port
Onboard Data Storage: Not required
Max PCB Size: 3.775”x3.550”
Voltage Supply: 120V/60Hz AC, 12V DC
Table 1: Specifications
EM Field Measurement Module for Embedded Computing 11
12. 2.3 Deliverables
At the completion of the project the deliverables include the two modules for L1 and L2
GPS frequencies that meet the stated customer specifications.
Along with the finished modules, a level 1 documentation package is submitted. The
level 1 documentation includes detailed instructions for the reconstruction of identical modules.
For this purpose, it contains hardware part numbers, software source code, as well as user
operation instructions. The documentation also incorporates designer recommendations for
future upgrades or changes.
2.4 Project Planning
This project was quality driven. The amount of time and money available was sufficient
and was recognized to be sufficient from an early stage in the project. This project began on
September 22nd
, 2004 and the final modules are being sent to NAWC-WD on May 5th
, 2005. It is
being competed on time and under budget. Illustration 1 is the critical path that was followed and
indicated when money was spent.
Illustration 1: Critical Path
EM Field Measurement Module for Embedded Computing 12
13. 2.4.1 Budget
There was $5400 available to develop these two modules. The final budget only spent
$2654 which is less than half of the available funds. Each additional module should cost about
$1200 in materials.
One of the reasons the budget was kept as low as it is, is due to free samples and
donations from Analog Devices, Maxim, Ztec Instruments, and the NMT EE Department.
Another reason for low expenses is proper planning. The design did not change significantly
after the design was finalized and the purchase orders were sent.
2.4.2 Human Resource Management
The project began with some background research and initial design brainstorming. After
the design was finalized and parts were received, there were several parallel paths. Software
development, PCB layout and prototyping, and housing assembly were the three long poles. All
three finished testing at about the same time in late April which allowed for a couple weeks of
final testing, optimization, and bug fixes. See Appendix A for the detailed gantt chart.
Component Unit Price Quantity Price
Antenna 177.50 2 355.00
Filter 125.00 3 375.00
Attenuator 35.00 4 140.00
Amplifier 290.00 2 580.00
Signal Splitter 250.00 2 500.00
Logarithmic Detector 0.00 4 0.00
Microcontroller 6.00 4 24.00
RS-232 Converter/Adapter 0.00 2 0.00
Power Converters/ Regulators 20.00 2 40.00
Packaging 70.00 2 140.00
Miscellaneous 500.00 1 500.00
Total 2654.00
Available 5400.00
Table 2: Budget
EM Field Measurement Module for Embedded Computing 13
14. Chapter 3: Project Design
3.1 Preliminary Design
The preliminary design consisted of seven distinct blocks. There is an antenna, amplifier,
selector, filter, power meter, micro-controller, and power system. Illustration 2 shows the blocks
and the interactions between them. The primary differences between the final design and the
preliminary design are in the amplification stage and the type of power meter used.
3.1.1 Cascading Amplifier and Selector
The specifications require that the modules accurately measure field strength between
-80dBm and +30dBm. This posed a problem with noise at the low power signals and
Illustration 2: Original Block Diagram
EM Field Measurement Module for Embedded Computing 14
15. overpowering circuitry at the high power signals. The original proposed solution used a
combination of low-noise, cascading amplifiers and attenuators. There would also have had to
been a fuse or other fast disconnect device to prevent overloading circuitry.
The cascading amplifiers and attenuators would be characterized and then controlled by
the microcontroller. If the signal entering the power meter and A/D converter is saturated or the
resolution is too poor, the microcontroller would increase or decrease amplification by turning
stages of attenuation and amplification on and off. Most commercial IC power meters are
accurate within a 20dB range, typically 0dBm to -20dBm. Therefore, each amplifier would have
to have a resolution of about 20dBm. Everything needed to be low noise to maintain the validity
of -80dBm signals. Shielding around the entire amplifier block would also help prevent aberrant
signals from being measured.
The amplifier and attenuators would need to be thoroughly tested. Every combination of
Illustration 3: Cascading Amplifier
EM Field Measurement Module for Embedded Computing 15
16. amplification and attenuation must be tested for noise, insertion loss, VSWR, and actual
amplification. A combination of spectrum analyzers, function generators, and oscilloscopes will
be able to do this testing and calibration
The selector was a combination of RF and power switching devices. It must accept the
control signals from the microcontroller, power the appropriate amplifiers, and forward the
correct amplified RF output. Illustration 3 is an example of what would happen when measuring
a -50dBm signal. The microcontroller would send the signal for 80dB amplification and the
selector would forward the fourth amplifier's output.
This design could theoretically work, but was plagued with noise issues. Each amplifier
would generate noise when powered, so when receiving a low power signal, all the stages of
amplification would be turned on. This noise could have potentially been amplified enough to
drown out the signal being measured. Another issue with this design was the open architecture
spec. In order to change the power detection range, stages of amplification would have to be
added or removed, or the amount of amplification on each stage would have to vary. The cascade
of amplifiers would have been a line of IC’s, thus switching them out or adding/removing stages
of amplification could not be done easily.
3.1.2 Power Meter
The original design for the power detector was a rectifier and peak detector designed out
of discrete components. This idea had a few problems including noise, switching times,
reliability, and low power range. The long circuit wires and distances between components
resulted in large noise issues. The requirement to reset the peak detector required more
connections to the microcontroller and a more complicated software routine to get data from the
detector. A professionally made IC is a much better choice.
EM Field Measurement Module for Embedded Computing 16
17. There are several companies that make an IC capable of converting an RF signal into a
DC voltage. They all seem to have about the same limitations. They operate between 3 and 5
volts and have very low current draw. The output is typically an analog DC signal between 0
volts and the operating voltage. The hardest part to deal with is the input has to be between
specific values (e.g. 0 and 20 dBm) which is why the amplifier, selector, and filter setup were so
complicated.
3.2 Present Design
The final design is broken down into the RF front end, the analog and digital
components, software and the enclosure. A simple block diagram is shown in Illustration 4. The
Illustration 4: Final Block Diagram
EM Field Measurement Module for Embedded Computing 17
18. blue lines indicate the path of the RF signal. The signal is captured by the antenna and filtered. It
is then split and sent through two channels, one for amplification and the other for attenuation.
Logarithmic detectors convert the two channels power values into voltages the microcontroller
can use to determine the EM field strength. The green solid lines represent DC voltages and DC
signals. The red lines indicate power, and the green dashed box is shielding that surrounds the
entire enclosure. The entire box is shielded to prevent external noise from affecting the circuitry
and also to prevent internal circuitry from affecting the antenna reception.
3.2.1 RF Front End Design
The RF front end is composed of the antenna, filtering, a signal splitter, amplification and
attenuation, and logarithmic detectors interfacing to the microcontroller.
Since two modules are going to be constructed, two separate antennas were ordered. One
antenna is strictly L1 and the other is a dual band L1/L2 antenna. Both of them are 50ohm
antennas The antennas are passive, so have approximately zero gain. The passive antennas are
chosen because the output voltage from an antenna receiving a +30dBm signal is about 7V. If
the antenna were to amplify that by 20dB, the output voltage would be about 70V. It is easy
enough to acquire components that can handle 7V but 70V is nearly impossible. The antennas
use a standard connector type, SMA, to facilitate interchangeability and noise reduction. The L1
antenna’s reflection pattern, as shown in Illustration 8, shows it have a clean bandpass filter
design centered around 1.57542 GHz. This is exactly as expected and desired, so only a single
GPS L1 filter was required in the L1 module. The L2 module’s antenna is a dual band antenna,
and its reflection pattern is far from ideal or desired, as shown in Illustration 7. If only a single
GPS L2 filter is used in the L2 module, only 20dBm of frequency isolation is achieved. To
increase our isolation and our accuracy, an extra GPS filter is added in line between the antenna
EM Field Measurement Module for Embedded Computing 18
19. and the signal splitter. This allowed for an acceptable value of 40dBm of frequency isolation.
Next the signal is sent into a GPS splitter, to create two channels so the power detection
range of –80dBm to +30dBm is possible. The logarithmic detectors used (Analog Device's
AD8313) have detection ranges roughly from –65dBm to 5dBm at frequencies being measured.
This is slightly smaller than the specification range. So two channels are created, one channel
going through a amplifier of 30dBm and the other channel through a 30dBm attenuation. The
attenuator is a passive device and is simply connected in-line through its SMA connector. The
amplifier is a active device that requires power through a bias-tee. The bias-tee has two inputs
and one output, all SMA connections. One input is the RF signal from the splitter, and the other
is 3.3V DC power. The output is a combination of RF and DC, sent into the input of the
amplifier. Thus the amplified channel will be able to detect measured field strength values
ranging roughly from –100dBm to –20dBm, and the attenuated channel will be able to detect
field strength values ranging roughly from -40dBm to +40dBm. Using the two channels
dynamically will give power range needed.
The logarithmic detectors output a voltage range from 0.7V to 1.7V varying linearly with
the power coming into the device. See Illustration 14 for actual results. Comparing the voltage
out of the logarithmic detectors with a calibrated look up table, the microcontroller will be able
to discern which channel is valid, and output the correct data through the RS-232 port. This
process will be described later in the software section.
3.2.2 Analog and Digital Design
There are three main components to the analog and digital portion of these modules: the
microcontroller, the RS-232 converter, and the power regulators. Appendix C has the final PCB
layout which shows all the connections and requirements.
EM Field Measurement Module for Embedded Computing 19
20. The microcontroller used is a PIC18F1320. Although the 1320 has 18 pins, this design
only requires seven of them. Two pins are used for 3.3V and Ground (pins 5 and 14), a second
pair of pins is used for transmitting and receiving RS-232 data (pins 9 and 10), another two pins
are used as analog inputs to the on-chip analog to digital converters (pins 1 and 2), and the final
pin is used as a digital control line for the amplifier's power switch (pin 3). If future designs
require additional sampling channels pins 6 through 8 can be used as additional ADCs.
Since the output of the microcontroller RS-232 pins are TTL signals, a RS-232 to TTL
level converter was needed. This design uses a Maxim MAX3232 RS-232 Transceiver to
accomplish this task. Illustration 5 has the circuit diagram that was used to connect and use the
MAX3232. View Appendix C for the final PCB layout.
The operating voltage of all the integrated circuits and RF amplifier is 3.3V. Since the
specification required that the modules use 120V/60Hz and 12V power sources, a AC/DC
converter and a voltage regulator was required. A Cincon CFM1002S power supply was used for
its size and efficiency. The CFM1002S can supply up to 10W which is sufficient for these
Illustration 5: MAX3232 Circuit Diagram
EM Field Measurement Module for Embedded Computing 20
21. modules. In order to prevent damage to the PCB, ICs, and power supplies, two diodes are used to
separate the dual power source options. In the event that both sources are plugged in, the diodes
will only allow current to flow in one direction and prevent shorts. A LM2937-3.3 was used to
convert 12V down to 3.3V. The LM2937 was chosen for its small size, high power capacity, and
excellent voltage regulation. See Illustration 6 for the LM2937 circuit diagram.
3.2.3 Software
The software for the PIC18F1320 was written using Microchip's MPLAB C18
development environment and compiler. This environment was chosen for its claimed ANSI C
compliance and microcontroller support. During the bug fixing portion of the project, several
bugs were found in the C18 compiler. It is recommended that any future work done on this
project should include switching to a new compiler as there are several other C compilers for the
18F1320.
Due to space limitations and the goal of having a simple user interface, there are only five
commands: Calibrate, Display Calibration Table, Get Data Point, Help, and Reset. Each
command is a single ASCII character and responds with ASCII character strings for user input.
The Calibrate command begins the calibration sequence. It asks the user to connect a
known power of the appropriate frequency to the input of the module. After getting a calibration
point at 5dBm steps, the user has to enter an antenna offset in dBm. This enables someone to
calibrate the antenna and the module separately.
Illustration 6: LM2937 Circuit Diagram
EM Field Measurement Module for Embedded Computing 21
22. The Display Calibration Table displays all the calibration points from -80dBm to 30dBm
as well as each channel's minimum and maximum accurate measurement. Viewing this helps to
debug any inaccuracies or nonsensical data.
The Get Data Point command polls the ADCs and converts those numbers into a dBm
value which is sent back to the user. The conversion function verifies limits and averages points
if more than one channel has valid data.
The Help command displays the available commands. The Reset command performs a
software restart. This command does not empty any data in EEPROM.
Appendix D has all of the source code. The Level 1 Documentation package has the
project files and compiled code.
3.2.4 Enclosure
For the enclosure, the size of the components, along with the connecting cables and the
different schemes the parts could be laid out in, were considered. The final setup has the GPS
filter on ½” aluminum standoffs, with the splitter stacked above it. In the L2 module there is the
added filter stacked in the middle. This stack is located on one end of the enclosure base. The
PCB board is located on the opposite end, with the power supply facing upwards for ease of
connecting the RF components to the SMA jacks on the board. The PCB is supported by four 2”
aluminum standoffs. Running on one side between the filter/splitter stack and the PCB is the
bias-tee and the attached amplifier. The amplifier is also held up by ½” aluminum standoffs.
Running along the other side is the attenuated line to the PCB.
Three main materials were considered for the construction of the enclosure that are easily
accessible, inexpensive, and maneuverable: Those are steel sheet, aluminum alloy sheet, and
EM Field Measurement Module for Embedded Computing 22
23. polymer based materials. Because the module deals with low power signals, shielding is
important to prevent interference into internal components from external sources. Steel and
aluminum are good conductors, thus providing good shielding. In the other hand, polymer or
plastic materials collect static charge which is harmful to sensitive internal components.
The enclosure is designed to have multiple bends and holes. Some factors that need to be
considered is the material tensile strength and ductility. Steel has a higher tensile strength which
consequentially makes it more brittle. Aluminum in the other hand, is more ductile and can
experience greater deformation without fracture. Other benefits of aluminum is weight, and
corrosion resistance. Therefore, an aluminum alloy sheet was selected for the construction of the
enclosure.
The sheet used for the base (See Appendix B) is 16”x11”. The 5”x11” sections (marked
off with a dashed line) on the left and right sides of the sheet would become walls of the base.
The center 6”x11” section would become the bottom of the module. Straight through, non-
threaded holes were drilled as indicated in the center base to connect the standoffs to support the
various components. On the right wall section holes for the DC power jack(3/8” diameter), the
fuse (1/2” diameter) and a cut out rectangle (3/4” by 1”) to hold the AC power jack were made.
On the left wall section, a standard DB9 connector punch was used to make the hole for the RS-
232 serial connection. Four, size 6-32 tapped holes are drilled on each wall as indicated on the
diagram, to secure the top to the base. If a courser thread type is desired, a thicker sheet would
need to be used to ensure that the bolts have enough thread to bite into.
The sheet used for the top (see Appendix B) is 21.2”x7.25”. On the top and bottom of the
sheet, 5” in from the left and right side, four isosceles right triangles are cut out. This is to allow
for the bend in each flap. Next eight holes are drilled, four in the top and four in the bottom as
EM Field Measurement Module for Embedded Computing 23
24. shown. The holes are straight through, non-threaded and have a diameter near .2”, large enough
to allow the #6-32 screws without passing the head. Another hole is drilled on one end of what
will become the top, with a diameter of ¼”. This will accept a female SMA connector type,
which can be secured from the outside, and will hold the modules antenna. All along the top and
bottom of the sheet, a line ½” from the edge is made. A 90 degree bend is made along both these
lines, creating securing lips for the lid. Two more 90 bends are made along lines connecting the
cut-out triangles along the 5” line as shown in the diagram.
To protect the internal circuitry from external noise, and also the antenna from internal
noise, 90 dBm shielding is lined inside the lid and the base. Then the individual components can
be placed inside, and the module top and bottom be fit together and secured with #6-32 bolts.
EM Field Measurement Module for Embedded Computing 24
25. Chapter 4: Results
4.1 Subsystem Specifications
Each component in the RF front ends were checked before being used in a larger
subsystem to verify operation. Illustration 8 has the L1 antenna reflection pattern. It indicates
that the antenna picks up L1 signals very well and almost nothing else. On the other hand,
Illustration 7 has the L1/L2 antenna reflection pattern which indicates that the antenna picks up
almost any frequency. That is why an extra L2 antenna was necessary. Illustrations 9 and 10
have the L1 filter and L2 series filters transfer graph. Both indicate sufficient stopband
attenuation and manageable insertion loss. Finally, Illustrations 11, 12, and 13 are the power
splitter's, amplifier's, and attenuator's transfer graph. The splitter and attenuator are flat which
means it won't have to be replaced if the module is changed to another frequency. The amplifier
has additional attenuation at lower frequencies so will not have to be replaced if the module is
Illustration 8: L1 Antenna Reflection Pattern Illustration 7: L1/L2 Antenna Reflection Pattern
EM Field Measurement Module for Embedded Computing 25
26. changed to another frequency.
Illustration 9: L1 Filter Transfer Illustration 10: L2 Filters Transfer
EM Field Measurement Module for Embedded Computing 26
27. Illustration 12: Atenuator Transfer
Illustration 13: Amplifier Transfer
EM Field Measurement Module for Embedded Computing 27
28. 4.2 Reliability
4.2.1 Mean Time Between Failures
MTBF is a predicting tool measured in hours, which indicates the sturdiness of the device
– the average time the device will function before breakdown based on collective testing by
manufacturer. The calculation is defined by the following formula:
MTBF = Total Hours of Operation/Outage Frequency
The following is a table of individual components' MTBF and failure rates in the system:
The MTBF of the complete system is calculated from the individual components' MTBF (θ).
Taking the failure rate (λ = 1/θ), the total system's MTBF is the inverse of the sum of individual
failure rates: MTBF total = 1/∑λ. This calculation is based on components in serial operation.
The calculated system's MTBF is approximately 70,000 hours.
4.2.2 Availability
Availability is the probability that the system is operational when called upon its function
quantified as a percentage. The availability takes into account both failures and repair time. The
equation for calculating the availability is the following:
A = MTBF/(MTBF + Repair Time)
Component MTBF (hours) Failure Rate (1/hours)
Antenna 1.00E+06 1.00E-06
Amplifier 1.00E+06 1.00E-06
Attenuator 1.00E+06 1.00E-06
Filter 1.00E+06 1.00E-06
Bias Tee 6.00E+05 1.67E-06
Splitter 1.00E+06 1.00E-06
Power Detectors 1.00E+08 1.00E-08
Power Detectors 1.00E+08 1.00E-08
Microcontroller 1.50E+05 6.67E-06
RS-232 Converter 5.00E+08 2.00E-09
Power Regulators 1.05E+08 9.52E-09
Software 1.00E+06 1.00E-06
Table 3: MTBF
EM Field Measurement Module for Embedded Computing 28
29. The repair time of each component in the module has an average of 24 hours. This includes
replacement of components and calibration of power values in the micro-controller. The total
availability of the system takes in account the total MTBF with the repair time of each
component:
A = (70,000/(70,000 + 24)) x100% = 99.966%
4.3 System Specifications
The final modules almost meet all of the specifications. The only specification that was
not completely met is the power range. Instead of -80 to 30 dBm, the modules have only been
successfully tested from -75dBm to 15dBm. Part of the untested region is due to lack of
equipment. The available test equipment was only accurate up to 15 dBm.
After assembling the modules and calibrating the look-up table, the illustration 14 was
compiled. This graph shows that the module has distinct, repeatable outputs for the entire input
range. The third (orange dotted) line is the attenuated channel output before the microcontroller
controlled power switch was added.
Illustration 14: ADC Output vs. dBm
EM Field Measurement Module for Embedded Computing 29
30. Chapter 5: Conclusion
The modules are completely operational. The final modules meet the specifications very
closely. Most of the challenges that emerged in the process originated mostly from design issues, which
were addressed after multiple revisions. Other technical issues allowed the team to understand topics
that are associated with RF type design such as noise, calibration issues, and data processing. However,
there are several suggestions for future improvement of the module design and operation.
For the microcontroller and software, it is advisable to have ample memory and a compiler that
optimizes the code based on the specific processor. Any future work done on this project should
include a switch to a new compiler and/or a microcontroller with additional data memory.
Because some noise leakage was experienced between channels, a switching device was
implemented later in the project to solve the problem. However, this problem could be avoided in the
PCB layout design. The attenuated, amplified, and power channels must be separated as much as
possible to prevent any leakage between channels. Along with shielding, this approach saves
computation for the processor. It also allows for an easily scalable design because the software
wouldn't need to know which channel is amplified.
Development management is very important for the success of the project. Some challenges
included coordination of tasks. Although the distribution of tasks was intended to be equal, the
completion times were not foreseen. A suitable strategy is to maintain a balanced distribution of tasks,
and alternative parallel approaches in case of premature or prolonged completion of assignments. This
can be achieved by maintaining logs and inter-team progress reports.
EM Field Measurement Module for Embedded Computing 30
31. Chapter 6: References
Bethune, James D. Engineering Graphics with AutoCAD. Prentice-Hall Inc. 1995.
Callister, Jr. William D. Materials Science and Engineering An Introduction, 5th
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and Sons Inc. 2000.
Carr, Joseph J. Elements of Electronic Instrumentation and Measurement, 2nd
Ed. Prentice-Hall
Inc. 1986.
Dana, Peter H. (2005, May 4). Code Phase Tracking (Navigation). [WWW] URL
http://www.colorado.edu/geography/gcraft/notes/gps/gps.html.
GPS World. (2005, May 4) GPS Reference [WWW] URL
http://www.gpsworld.com/gpsworld/static/staticHtml.jsp?id=7860.
Hill, Winfield and Paul Horowitz. The Art of Electronics, 2nd
Ed. Cambridge University Press.
1989.
Iskander, Magdy F. Electromagnetic Field and Waves. Waveland Press Inc. 1992.
Kernighan, Brian W. and Dennis Ritchie. C Programming Language, 2nd
Ed. Prentice-Hall PTR.
1988.
Neamen, Donald A. Electronic Circuit Analysis and Design. Times Mirror Higher Education
Group Inc. 1996.
Sedra, Adel and KC Smith. Microelectronic Circuits, 4th
Ed. Oxford University Press. 1998.
Smith, Richard F.M. And Stanley Wolf. Student Manual: Electronic Instrumentation
Laboratories, 2nd
Ed. Pearson Education Inc 2004.
Wikipedia. (2005, May 4) dBm [WWW] URL http://en.wikipedia.org/wiki/DBm.
Wikipedia. (2005, May 4) Global Positioning System [WWW] URL
http://en.wikipedia.org/wiki/GPS.
EM Field Measurement Module for Embedded Computing 31
32. Appendix A: Gantt Chart
EM Field Measurement Module for Embedded Computing 32