Page 1. WE2B-4 INFLUENCE OF COLLECTOR DESIGN ON InGaP/GaAs HBT LINEARITY Masaya Iwamoto, Tom S. L... more Page 1. WE2B-4 INFLUENCE OF COLLECTOR DESIGN ON InGaP/GaAs HBT LINEARITY Masaya Iwamoto, Tom S. Low*, Craig P. Hutchinson', Jonathan B. Scott*, Alex Cognata", Xiaohui Qin*, Lovell H. Camnitz**, Peter M. Asbeck, Don C. D'Avanm* ...
Abstract—Advances in microwave instrumentation now make it feasible to accurately measure not onl... more Abstract—Advances in microwave instrumentation now make it feasible to accurately measure not only the magnitude spectrum, but also the phase spectrum of wide-bandwidth signals. In a practical measurement, the spectrum is measured over a finite window of time. The phase spectrum is related to the position of this window, causing the spectrum to differ between measure-ments of an identical waveform. It is difficult to compare multiple measurements with different window positions or to incorporate them into a model. Several methods have been proposed for deter-mining the phase spectrum such that multiple measurements can be effectively compared and utilized in models. The methods are reviewed in terms of the information required to determine the phase and compared in terms of their robustness in the presence of measurement noise. Index Terms—Intermodulation distortion, measurement uncer-tainty, nonlinear systems, phase measurement. I.
Abstract—We describe a state-of-charge, or “residual-capacity ” meter for lead-acid batteries tha... more Abstract—We describe a state-of-charge, or “residual-capacity ” meter for lead-acid batteries that intelligently syn-thesizes coulometric and terminal-voltage methods in a new algorithm to provide reliable, continuous readout of remaining capacity. Novel electronic circuit design eliminates the need to install a shunt in the vehicle. The meter learns the characteristics of a battery to which it is attached, removing the need for setup, customisation, programming or calibration at time of installation or battery replacement. The meter can thus be installed by unqualified personnel. Initial measurements suggest the design to be robust and accurate. I.
Modern electric fences have remote controls and remote monitors that communicate with the energiz... more Modern electric fences have remote controls and remote monitors that communicate with the energizer through the active fence wire. This manuscript looks at the impact of repair joints on the data communications between energizer and remotes. We report measurements of nonlinear rust-induced characteristics in joints and we draw conclusions about their effects in the context of an electric fence carrying data communications signals. We furthermore demonstrate how their nonlinear characteristics can cause mixing and detection effects that could account for radio reception.
This manuscript reports the Threshold Concepts (TCs) identified in early circuits and electronics... more This manuscript reports the Threshold Concepts (TCs) identified in early circuits and electronics courses through our work to date. We suggest some novel methods used to quantify the identification. We identify some concepts that ought to have been mastered in high-school physics courses but that are often absent from student repetoires. This may be a confusing factor for us and a source of trouble for students.
This manuscript presents a very low-cost circuit using a PIC12F683 microcontroller and an LM285 b... more This manuscript presents a very low-cost circuit using a PIC12F683 microcontroller and an LM285 bandgap voltage reference that provides an expanded-scale to an analog panel meter suitable for monitoring a single Lithium-ion battery. Charge or discharge of the cell is indicated by periodic twitches of the needle to the left or the right. The design is especially suitable for small devices subject to intermittant use or that recharge by power-harvesting. The design is open-source, with circuit, board layout, and source code provided.
First electronics courses are considered difficult by students because of the circuit theory cont... more First electronics courses are considered difficult by students because of the circuit theory content, and retention of students in electronics is a problem worldwide. Retention is especially problematic at universities that offer a common first-year program since the students can change streams, for example from Electrical to Mechanical. At our university we ran the laboratory classes for a challenging first-year electronics course in the same room at the same time as a popular final-year mechatronics class that involved visible use of Lego Mindstorms, a model elevator, digital model trains and slot cars, etc. We report the outcomes of a quantitative and qualitative study of the impact of this organisation. One lab stream did not see the parallel classes and thus acted as a control group.
We present theory and measured performance of an autonomous slot car driven by a heuristic algori... more We present theory and measured performance of an autonomous slot car driven by a heuristic algorithm on a typical track. The hardware consists of a PIC 8-bit single-chip microcontroller with various sensors driving a standard permanent-magnet (PM) brushed dc (BDC) motor in a mechanically-standard Scalextric platform. We present some interesting results concerning the relative difficulty of apparently-balanced lanes on a track. The car achieves optimum lap times with high consistency. Measured performance agrees with theoretical expectation. The consistency of performance allows the impact of experimental changes to be reliably assessed.
In this paper we present the first proof that a Darlington transistor has an inherent nulling eff... more In this paper we present the first proof that a Darlington transistor has an inherent nulling effect in its third-order intermodulation distortion, similar to the well known third-order null seen in single BJT amplifiers. It is proven mathematically and by measurement. The results suggest the null actually becomes feasible as a source of distortion reduction in a Darlington BJT amplifier.
The RF fields present in magnetic resonance imaging (MRI) scanners can induce hazardous heating i... more The RF fields present in magnetic resonance imaging (MRI) scanners can induce hazardous heating in patients wearing medical implants. The inherent design and locale of deep brain stimulators (DBS) and spinal cord stimulators (SCS) make them particularly susceptible. We apply antenna concepts and use electromagnetic (EM) simulation to explain the phenomenon and anticipate its sensitivity to lead wire length. We anticipate that a DC resistance of less than 50Ω/m and an RF impedance of more than 1.23kΩ/m would be required for a safe electrode for SCS use. We investigate the possibility of manipulating wire conductivity and diameter in order to use the skin depth effect to achieve a safe electrode. The effect of the thickness and permittivity of insulation surrounding the wires is explored.
The traditional stimulus signal used in a time-domain reflectometer (TDR) is a voltage step. We p... more The traditional stimulus signal used in a time-domain reflectometer (TDR) is a voltage step. We propose an alternative technique, whereby an impulse generator is employed in place of the step generator in a TDR. The advantage conferred by “impulse TDR” is that more energy is available at higher frequencies than with conventional step TDR, and so a higher bandwidth and signal-to-noise ratio (SNR) is achieved. The theoretical result is compared with measurement.
We describe the design and implementation of a cup anemometer capable of logging average wind spe... more We describe the design and implementation of a cup anemometer capable of logging average wind speed, maximum wind speed and seconds with wind above a criterion speed, on individual weeks. The instrument will operate for at least 54 weeks on two AA dry cells. The intention is that this instrument be deployed to ascertain whether it would be economical to install a wind generator, at a fraction of the cost of a multipurpose weather data logging station. It is designed around a $2 microcontroller that provides non-volatile memory. Provision has been made for using either a magnetic reed switch or the motor from a discarded hard disk drive to sense rotation. The latter enables the use of an otherwise worthless bearing and drive assembly to provide an especially frugal solution.
CONTEXT The flipped-classroom model is a recent educational development that is prominent in the ... more CONTEXT The flipped-classroom model is a recent educational development that is prominent in the literature on learning. The typical flipped class scenario involves students looking up information, reading printed materials or watching videos prior to gathering in a classroom to apply the knowledge through problem solving activities with guidance from the teacher. However, there is little research available about the effects of the flipped class on students’ learning in large introductory engineering courses with a strong lab component that must be conducted in multiple streams. This current research is based at one New Zealand university with engineering student enrolments of typically 150 students. In the past few years, prior to the introduction of the flipped class, the course lecturers have been refining the teaching of the course through a focus on threshold concepts (TCs) and the introduction of online tutorials.
This equation is described as a “transfer function”. This is confusing and can mislead readers be... more This equation is described as a “transfer function”. This is confusing and can mislead readers because it is an impedance (one-port) rather than a transfer (two-port) function. The authors also use V = Vo − Voc instead of V = Voc − Vo, meaning that their equation actually seeks the negative of the impedance, given the direction they have chosen for the conventional current I(s). More importantly, the equation is simply incorrect. The individual impedance elements are multiplied instead of being summed. The correct equation has addition rather than multiplication signs, so:
Patients wearing Deep Brain Stimulators or Spinal Cord Stimulators implants experience heating at... more Patients wearing Deep Brain Stimulators or Spinal Cord Stimulators implants experience heating at radio frequencies when subjected to an Magnetic Resonance Imaging (MRI) scan that operates at a frequency of 128MHz. One technique to mitigate this heating is applying the concept of loss due to skin-effect on an implant lead wire at MRI frequency. A coaxial resonator of quarter-wavelength with copper conductors was constructed to test the insertion loss using a Vector Network Analyser. The smooth inner copper rod was compared with rough inner copper rod to determine the difference between the qualityvalue of the resonator. Roughening the surface does enhance the skin-effect loss but the loss is insufficient to translate it to an implant lead which is inserted in a patient.
Measurement of impedance of rechargeable batteries at very low frequencies reveals valuable infor... more Measurement of impedance of rechargeable batteries at very low frequencies reveals valuable information relating to battery behaviour and condition. Until now, successful measurements have been made in the laboratory with bench analysers. This requires batteries to be taken out of service for periods ranging from hours to days, which is impractical for units that are needed for continual use or that are difficult to remove for analysis (e.g. electric vehicles), or that are difficult or impossible to access (e.g. satellites, implanted medical devices, distant data centres). We describe a simple microprocessor-based circuit that draws current at a number of frequencies and provides voltage and current data that can be logged and used to calculate the impedance of batteries in situ.
Even electronics people are surprised to learn that the vacuum device industry is still a thrivin... more Even electronics people are surprised to learn that the vacuum device industry is still a thriving US$1B business. The tube presided over the electronics revolution, including the fastest-ever penetration of a technology into society—that is the arrival of broadcast radio in the 1920s, not the cellphone in the 1990s—but the vacuum tube also remains far ahead of solid-state alternatives in power-bandwidth. Electronics people are often surprised to learn that Silicon, as a technology for transistors, is superior only in price (and volume). It was not the first solid-state vehicle, Germanium was. It is not the fastest, the so-called III-V family of Gallium-Arsenide and Indium-Phosphide is. Cray supercomputers had a heart of GaAs. In fact, compound semiconductors (CS) in the form of GaAs enabled satellite communications, satellite TV, LEDs, radar, and fibre-optics. It is only recently that pure-silicon cellphones and TV dishes appeared. Hold a complex cellphone in your hand and you hold...
Page 1. WE2B-4 INFLUENCE OF COLLECTOR DESIGN ON InGaP/GaAs HBT LINEARITY Masaya Iwamoto, Tom S. L... more Page 1. WE2B-4 INFLUENCE OF COLLECTOR DESIGN ON InGaP/GaAs HBT LINEARITY Masaya Iwamoto, Tom S. Low*, Craig P. Hutchinson', Jonathan B. Scott*, Alex Cognata", Xiaohui Qin*, Lovell H. Camnitz**, Peter M. Asbeck, Don C. D'Avanm* ...
Abstract—Advances in microwave instrumentation now make it feasible to accurately measure not onl... more Abstract—Advances in microwave instrumentation now make it feasible to accurately measure not only the magnitude spectrum, but also the phase spectrum of wide-bandwidth signals. In a practical measurement, the spectrum is measured over a finite window of time. The phase spectrum is related to the position of this window, causing the spectrum to differ between measure-ments of an identical waveform. It is difficult to compare multiple measurements with different window positions or to incorporate them into a model. Several methods have been proposed for deter-mining the phase spectrum such that multiple measurements can be effectively compared and utilized in models. The methods are reviewed in terms of the information required to determine the phase and compared in terms of their robustness in the presence of measurement noise. Index Terms—Intermodulation distortion, measurement uncer-tainty, nonlinear systems, phase measurement. I.
Abstract—We describe a state-of-charge, or “residual-capacity ” meter for lead-acid batteries tha... more Abstract—We describe a state-of-charge, or “residual-capacity ” meter for lead-acid batteries that intelligently syn-thesizes coulometric and terminal-voltage methods in a new algorithm to provide reliable, continuous readout of remaining capacity. Novel electronic circuit design eliminates the need to install a shunt in the vehicle. The meter learns the characteristics of a battery to which it is attached, removing the need for setup, customisation, programming or calibration at time of installation or battery replacement. The meter can thus be installed by unqualified personnel. Initial measurements suggest the design to be robust and accurate. I.
Modern electric fences have remote controls and remote monitors that communicate with the energiz... more Modern electric fences have remote controls and remote monitors that communicate with the energizer through the active fence wire. This manuscript looks at the impact of repair joints on the data communications between energizer and remotes. We report measurements of nonlinear rust-induced characteristics in joints and we draw conclusions about their effects in the context of an electric fence carrying data communications signals. We furthermore demonstrate how their nonlinear characteristics can cause mixing and detection effects that could account for radio reception.
This manuscript reports the Threshold Concepts (TCs) identified in early circuits and electronics... more This manuscript reports the Threshold Concepts (TCs) identified in early circuits and electronics courses through our work to date. We suggest some novel methods used to quantify the identification. We identify some concepts that ought to have been mastered in high-school physics courses but that are often absent from student repetoires. This may be a confusing factor for us and a source of trouble for students.
This manuscript presents a very low-cost circuit using a PIC12F683 microcontroller and an LM285 b... more This manuscript presents a very low-cost circuit using a PIC12F683 microcontroller and an LM285 bandgap voltage reference that provides an expanded-scale to an analog panel meter suitable for monitoring a single Lithium-ion battery. Charge or discharge of the cell is indicated by periodic twitches of the needle to the left or the right. The design is especially suitable for small devices subject to intermittant use or that recharge by power-harvesting. The design is open-source, with circuit, board layout, and source code provided.
First electronics courses are considered difficult by students because of the circuit theory cont... more First electronics courses are considered difficult by students because of the circuit theory content, and retention of students in electronics is a problem worldwide. Retention is especially problematic at universities that offer a common first-year program since the students can change streams, for example from Electrical to Mechanical. At our university we ran the laboratory classes for a challenging first-year electronics course in the same room at the same time as a popular final-year mechatronics class that involved visible use of Lego Mindstorms, a model elevator, digital model trains and slot cars, etc. We report the outcomes of a quantitative and qualitative study of the impact of this organisation. One lab stream did not see the parallel classes and thus acted as a control group.
We present theory and measured performance of an autonomous slot car driven by a heuristic algori... more We present theory and measured performance of an autonomous slot car driven by a heuristic algorithm on a typical track. The hardware consists of a PIC 8-bit single-chip microcontroller with various sensors driving a standard permanent-magnet (PM) brushed dc (BDC) motor in a mechanically-standard Scalextric platform. We present some interesting results concerning the relative difficulty of apparently-balanced lanes on a track. The car achieves optimum lap times with high consistency. Measured performance agrees with theoretical expectation. The consistency of performance allows the impact of experimental changes to be reliably assessed.
In this paper we present the first proof that a Darlington transistor has an inherent nulling eff... more In this paper we present the first proof that a Darlington transistor has an inherent nulling effect in its third-order intermodulation distortion, similar to the well known third-order null seen in single BJT amplifiers. It is proven mathematically and by measurement. The results suggest the null actually becomes feasible as a source of distortion reduction in a Darlington BJT amplifier.
The RF fields present in magnetic resonance imaging (MRI) scanners can induce hazardous heating i... more The RF fields present in magnetic resonance imaging (MRI) scanners can induce hazardous heating in patients wearing medical implants. The inherent design and locale of deep brain stimulators (DBS) and spinal cord stimulators (SCS) make them particularly susceptible. We apply antenna concepts and use electromagnetic (EM) simulation to explain the phenomenon and anticipate its sensitivity to lead wire length. We anticipate that a DC resistance of less than 50Ω/m and an RF impedance of more than 1.23kΩ/m would be required for a safe electrode for SCS use. We investigate the possibility of manipulating wire conductivity and diameter in order to use the skin depth effect to achieve a safe electrode. The effect of the thickness and permittivity of insulation surrounding the wires is explored.
The traditional stimulus signal used in a time-domain reflectometer (TDR) is a voltage step. We p... more The traditional stimulus signal used in a time-domain reflectometer (TDR) is a voltage step. We propose an alternative technique, whereby an impulse generator is employed in place of the step generator in a TDR. The advantage conferred by “impulse TDR” is that more energy is available at higher frequencies than with conventional step TDR, and so a higher bandwidth and signal-to-noise ratio (SNR) is achieved. The theoretical result is compared with measurement.
We describe the design and implementation of a cup anemometer capable of logging average wind spe... more We describe the design and implementation of a cup anemometer capable of logging average wind speed, maximum wind speed and seconds with wind above a criterion speed, on individual weeks. The instrument will operate for at least 54 weeks on two AA dry cells. The intention is that this instrument be deployed to ascertain whether it would be economical to install a wind generator, at a fraction of the cost of a multipurpose weather data logging station. It is designed around a $2 microcontroller that provides non-volatile memory. Provision has been made for using either a magnetic reed switch or the motor from a discarded hard disk drive to sense rotation. The latter enables the use of an otherwise worthless bearing and drive assembly to provide an especially frugal solution.
CONTEXT The flipped-classroom model is a recent educational development that is prominent in the ... more CONTEXT The flipped-classroom model is a recent educational development that is prominent in the literature on learning. The typical flipped class scenario involves students looking up information, reading printed materials or watching videos prior to gathering in a classroom to apply the knowledge through problem solving activities with guidance from the teacher. However, there is little research available about the effects of the flipped class on students’ learning in large introductory engineering courses with a strong lab component that must be conducted in multiple streams. This current research is based at one New Zealand university with engineering student enrolments of typically 150 students. In the past few years, prior to the introduction of the flipped class, the course lecturers have been refining the teaching of the course through a focus on threshold concepts (TCs) and the introduction of online tutorials.
This equation is described as a “transfer function”. This is confusing and can mislead readers be... more This equation is described as a “transfer function”. This is confusing and can mislead readers because it is an impedance (one-port) rather than a transfer (two-port) function. The authors also use V = Vo − Voc instead of V = Voc − Vo, meaning that their equation actually seeks the negative of the impedance, given the direction they have chosen for the conventional current I(s). More importantly, the equation is simply incorrect. The individual impedance elements are multiplied instead of being summed. The correct equation has addition rather than multiplication signs, so:
Patients wearing Deep Brain Stimulators or Spinal Cord Stimulators implants experience heating at... more Patients wearing Deep Brain Stimulators or Spinal Cord Stimulators implants experience heating at radio frequencies when subjected to an Magnetic Resonance Imaging (MRI) scan that operates at a frequency of 128MHz. One technique to mitigate this heating is applying the concept of loss due to skin-effect on an implant lead wire at MRI frequency. A coaxial resonator of quarter-wavelength with copper conductors was constructed to test the insertion loss using a Vector Network Analyser. The smooth inner copper rod was compared with rough inner copper rod to determine the difference between the qualityvalue of the resonator. Roughening the surface does enhance the skin-effect loss but the loss is insufficient to translate it to an implant lead which is inserted in a patient.
Measurement of impedance of rechargeable batteries at very low frequencies reveals valuable infor... more Measurement of impedance of rechargeable batteries at very low frequencies reveals valuable information relating to battery behaviour and condition. Until now, successful measurements have been made in the laboratory with bench analysers. This requires batteries to be taken out of service for periods ranging from hours to days, which is impractical for units that are needed for continual use or that are difficult to remove for analysis (e.g. electric vehicles), or that are difficult or impossible to access (e.g. satellites, implanted medical devices, distant data centres). We describe a simple microprocessor-based circuit that draws current at a number of frequencies and provides voltage and current data that can be logged and used to calculate the impedance of batteries in situ.
Even electronics people are surprised to learn that the vacuum device industry is still a thrivin... more Even electronics people are surprised to learn that the vacuum device industry is still a thriving US$1B business. The tube presided over the electronics revolution, including the fastest-ever penetration of a technology into society—that is the arrival of broadcast radio in the 1920s, not the cellphone in the 1990s—but the vacuum tube also remains far ahead of solid-state alternatives in power-bandwidth. Electronics people are often surprised to learn that Silicon, as a technology for transistors, is superior only in price (and volume). It was not the first solid-state vehicle, Germanium was. It is not the fastest, the so-called III-V family of Gallium-Arsenide and Indium-Phosphide is. Cray supercomputers had a heart of GaAs. In fact, compound semiconductors (CS) in the form of GaAs enabled satellite communications, satellite TV, LEDs, radar, and fibre-optics. It is only recently that pure-silicon cellphones and TV dishes appeared. Hold a complex cellphone in your hand and you hold...
Proceedings of EdMedia + Innovate Learning 2018 Conference, 2018
Flipped classrooms support student-centred learning and are increasingly being adopted in institu... more Flipped classrooms support student-centred learning and are increasingly being adopted in institutions of higher learning worldwide. This paper is a report on the findings of a two-year funded project conducted on the impact of adopting a flipped classroom approach on first-year undergraduate engineering students' learning in a New Zealand university. A design-based methodology was adopted to allow for five iterative course refinements. Data collected through student achievement data, surveys, focus group interviews, observations and video analytics of student video-watching behaviour indicated a significant improvement in students' learning and that they valued the flipped course components such as the lecturer-created instructional videos, in-class problem-solving exercises and continuous assessment in supporting their learning. However not all students prefer learning through this approach and more scaffolding is needed for first-year students to take up responsibility for their own learning. Implications for practice are offered.
Proceedings of the 29th Australasian Association of Engineering Education Conference 2018, 2018
Problem-based learning (PBL) helps engineering graduates develop the competencies needed in order... more Problem-based learning (PBL) helps engineering graduates develop the competencies needed in order to engage effectively with complex and uncertain workplace demands. PBL's effectiveness, however, also depends on students having the ability to manage themselves and to work collaboratively. As these professional competencies are not typically the focus of undergraduate engineering programmes, students tend to complete problem-based project work through their own initiatives without the skills relevant to project completion. On the other hand, project management competencies are commonly explicated and core in business and management disciplines. PURPOSE This paper reports on our project which addresses the research question: What is the impact of utilising a management-educated demonstrator to work with engineering students on their learning and development of project management competencies? APPROACH Our project intervention required students in a fourth-year advanced engineering problem-based course to regularly report their planning and project progress to a graduate management tutor (demonstrator manager). A third of the course marks was awarded by the tutor who provided business-informed coaching as feedback during each report planning session. Multiple forms of data were collected-pre-and post-course surveys, student focus group interviews, lecturer and tutor interviews and student formative and summative grades. RESULTS The findings highlighted that: (1) Students did gain a better understanding of key aspects of project management; (2) Students were generally supportive of the technique, but wanted more "introduction", exposing their naivete where grading on management was concerned; (3) The approach could foster more Engineering-Management collaboration at a university; (4) The approach supports the accreditation goal of developing engineering graduates' professional competencies related to management skills. CONCLUSIONS Given the multiple and complex challenges facing 21st-century society, engineering employers are increasingly seeking graduates who are both technical experts in their field and able to work with experts from other fields, including business and management. Our project contributes understandings on how interdisciplinary initiatives can develop such professional competencies that are important for engineering graduate work-readiness. KEYWORDS Interdisciplinary study, project management, problem-based learning
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Papers by Jonathan Scott
PURPOSE This paper reports on our project which addresses the research question: What is the impact of utilising a management-educated demonstrator to work with engineering students on their learning and development of project management competencies? APPROACH Our project intervention required students in a fourth-year advanced engineering problem-based course to regularly report their planning and project progress to a graduate management tutor (demonstrator manager). A third of the course marks was awarded by the tutor who provided business-informed coaching as feedback during each report planning session. Multiple forms of data were collected-pre-and post-course surveys, student focus group interviews, lecturer and tutor interviews and student formative and summative grades.
RESULTS The findings highlighted that: (1) Students did gain a better understanding of key aspects of project management; (2) Students were generally supportive of the technique, but wanted more "introduction", exposing their naivete where grading on management was concerned; (3) The approach could foster more Engineering-Management collaboration at a university; (4) The approach supports the accreditation goal of developing engineering graduates' professional competencies related to management skills.
CONCLUSIONS Given the multiple and complex challenges facing 21st-century society, engineering employers are increasingly seeking graduates who are both technical experts in their field and able to work with experts from other fields, including business and management. Our project contributes understandings on how interdisciplinary initiatives can develop such professional competencies that are important for engineering graduate work-readiness. KEYWORDS Interdisciplinary study, project management, problem-based learning