Roberto Rosales

Measurement study and transmission for in-vehicle power line communication

In-vehicle power line communication (PLC) holds great promises as an enabler of in-vehicle communication without increasing weight, volume, or cost of the wiring harnesses. In this paper, we join a few recent works and present channel measurements for a specific compact car. We discuss and compare our measurement results with those obtained in previous campaigns. Furthermore, we evaluate our measurements from the viewpoint of high connectivity. That is, we are interested in the suitability of PLC for applications that require a reliable link from any node to any other node at any time. Perhaps not surprisingly, we find that advanced transmission techniques such as multihop or frequency diversity are necessary to achieve this goal.

Crosstalk bounded uncorrelated jitter (BUJ) for high-speed interconnects

Bounded uncorrelated jitter (BUJ), a subcomponent of total jitter, is commonly caused by crosstalk coupling from adjacent interconnects on printed circuit boards (PCB). However, the characteristics of BUJ are still not well understood. Neither a mathematical model of jitter, nor an algorithm to generate histograms for BUJ has been developed to this date. Such a model and algorithm would empower designers to predict BUJ to achieve total jitter budget without lengthy simulations and measurements. In this paper, we first review the characteristics of a crosstalk pulse induced by an aggressor signal on a quiet trace. Then, by applying the superposition principle, a jitter model to calculate the time difference between the distortion-free and the distorted edge crossings of the victim signal was developed. This model is also extended to calculate the worst case timing difference, BUJ/sub p-p/. In addition, an algorithm to generate the histogram distribution of BUJ is also developed. The developed algorithm has fast execution times of 10-20 s, compared to simulation and measurement times of 10-30 min.

Channel characterization for power line communication in a hybrid electric vehicle

In todays electric and conventional combustion engine vehicles, data communication between electronic control units is accomplished by sending communication signals over dedicated wires. The space requirement, weight, and installation costs for these wires can become significant, especially in electric vehicles (EVs) of the future, which are highly sophisticated electronic systems. The concept of reusing existing electricity wires, which are needed to power electronic components, for data communication, i.e., vehicular power line communications (V-PLC), is thus a promising means to reduce the amount of dedicated wiring and/or establish redundant communication buses especially for EVs. Previous work on V-PLC has mostly focused on combustion engine vehicles. In this paper, we present the methodology and results from a measurement campaign with the goal of characterizing the transmission conditions for V-PLC in a hybrid EV (HEV). Emphasis is given to the choice of measurement points (potential nodes of a V-PLC network) and the proper design of adapters for measurement equipment. The results presented here focus on channel transfer function and access impedance.

A study on access impedance for vehicular power line communications

In this paper, we present an experimental study of access impedance for vehicular power line communications (VPLC). This study aims to provide better understanding of the effects of the vehicle loads on the impedance of the VPLC plug-in access nodes. Also, some insights for the design of adaptive impedance matching are provided. We report impedance measurements of various loads and car battery, which combined with input impedance measurements from a specific sport car are used to calculate an equivalent access impedance of a PLC device connected in parallel. We show how the inductive nature of the loads dominates the overall access impedance making it on one hand more attractive for transmission in the high MHz range, and on the other more challenging for the implementation of impedance matching.

Design of a Tunable Differential Ring Oscillator With Short Start-Up and Switching Transients

Timing measurements such as jitter and skew in the range of picoseconds, for circuits with multigigahertz clocks or multigigabit-per-second serial communication interfaces are common. A Vernier-oscillator-based time-to-digital converter (TDC) is a circuit that allows picosecond-timing measurements by means of two tunable oscillators. In such a circuit, the oscillator jitter, tuning response, start-up transient, and frequency switching transient play an important role in the TDCs measurement time and accuracy. In this work, we discuss the design of an optimized, differential CML-based ring oscillator and its impact on a TDC design. Simulation results from the new oscillator show that the oscillators short start-up and frequency switching transients have negligible effects on the accuracy of the TDC measurements. TDC simulation results show that, using two of these oscillators, accurate timing measurements in the range of 10 to 900 ps can be achieved with best-case accuracy of ~2 ps.

On the design of impedance matching circuits for vehicular power line communication systems

The design of power line communication (PLC) systems for vehicles, i.e., vehicular power line communication (VPLC), is a challenging task as propagation conditions are harsh and devices need to be low cost and highly integrated (to have minimal overhead on vehicles cost and weight). One particular challenge, which is common to many PLC application scenarios, is the temporal and spatial variation of the input impedance. In this paper, we investigate on this issue and, based on previous studies and measurements on access impedances for a PLC network in a car, we discuss the design of adaptive impedance matching circuits for VPLC. This includes a study on frequency range of operation, suggestions for impedance matching circuits, and proposing a circuit structure. In particular, since inductors are an integral part of matching circuitry and given that over the typical frequency range of operation for VPLC their integration is challenging, if not impractical, we advocate the use of active inductors in matching circuits. As compared to passive inductors, they occupy a smaller on-chip size and their inductance is adjustable. We also propose an active inductor structure that provides a wide range of inductance values which are suitable for VPLC applications.

Control Theory Practices Applied to Teaching Practical Control Theory

Copyright 2017 by ASME ABSTRACT Control theory is useful in a broad range of diverse applications that include mechanical, electrical and chemical systems. This work extends the application of control theory from achieving a desired technical outcome to achieving a desired pedagogical outcome. In this paper, the desired outcome is the teaching and learning of applied control systems theory. In the proposed model, the student is the plant, their skill set is the set point, the instructor is the controller, and either an exam or a project-based-learning (PBL) course is the sensor. The PBL course is used to evaluate the actual skill set of the students and the difference between the actual and desired skill set (error signal) is fed back to the professor to initiate curricular changes. This model is shown to be applicable at various levels. At the micro level, examinations within a course are used to optimize that course. At the intermediate level, a PBL course is used as the sensor for a conventional lecture-based course. At the macro level, the departmental program as a whole is matched to the needs of industry in pursuit of a 100% employment rate of its students. NOMENCLATURE DOF degrees-of-freedom ECE Electrical & Computer Engineering EC Electrically Commutated EE Electrical Engineering EEDS Electrical Engineering Design Studio ELEC-341 ECE Control Systems Course ELEC-391 ECE EEDS Course FDM fused deposition modeling (3D printing) LCR inductance / capacitance / resistance LTI linear time invariant OPDCA Observe / Plan / Do / Check / Adjust PA practical ability PBL project-based learning PID proportional, integral, derivative PLA polylactic acid (FDM material) RCG requirements, constraints and goals TA teaching assistant TK theoretical knowledge UBC University of British Columbia Proceedings of the ASME 2017 International Mechanical Engineering Congress and Exposition IMECE2017 November 3-9, 2017, Tampa, Florida, USA

Improving Project-Based Learning Outcomes by Formative Assessment and Strategic Time Optimization

The 3rd year Electrical Engineering Design Studio (EEDS) course is a project-based learning (PBL) course that gives students hands-on experience with putting electrical engineering principles into practice. It is an electro-mechanical project which provides a particular challenge since electrical engineering students often lack mechanical design skills. It is found here that learning outcomes are improved by a 2-stage formative assessment and time optimization strategy that allows students to extract as much value as possible out of the limited time they have to devote to this exercise. It consists of an innovative assessment strategy that includes formal, informal and self-assessments, and an innovative budgeting, lecture scheduling, parts distribution, and order queueing system. The impact on efficiency is shown through an end-of-term student survey and a subjective evaluation of their work, in comparison to the previous year.Copyright

Silicon bipolar circuits for wideband FM CATV transmission

In optical transmission of analog multi-channel cable television, an alternative to lower the cost of system components is that of employing wideband frequency modulation. This approach requires wideband FM modulation circuits with GHz operation and demanding linear performance. In this paper we describe wideband FM modulator and demodulator circuits implemented in a 25GHz-ft silicon bipolar technology, that show for the first time 80-channel transmission attainable. Most notably, the use of emitter coupled multivibrator VCOs achieved record modulator linearity over a 1.5-2.5GHz frequency range, and proved to outperform in linearity and noise the best wideband optoelectronic modulators. The demodulator response is linear over the range from 1-3.5GHz. Modulator phase noise is -122.5dBc/Hz @ 50MHz, and was found to be improvable through a novel phase noise reduction technique.

High linearity integrated silicon bipolar modulator for wideband FM CATV transmission

Lightwave CATV transmission based on intensity modulation by a multichannel CATV signal is simple, but requires very linear components and high received powers. Alternatively, the multichannel signal can be FM-modulated onto one RF carrier, and transmitted with conventional intensity modulation. However, optoelectronic modulators reported to date are complex and bulky, and an electronic approach is needed. We describe a wideband FM modulator with record linearity over a wide tuning range, and phase noise equal to the best optoelectronic modulator results. An emitter-coupled multivibrator (ECM) core coupled to a linear transadmittance amplifier drives fully-differential limiter and output driver circuits. With an ECM very wide linear tuning range can be achieved if appropriately-designed collector loads are used. The circuit was fabricated in Nortels NT-25 silicon bipolar process; the high-frequency layout is fully differential and physically symmetric. The ECM core operates at currents around 1 mA, optimized in conjunction with transistor sizing, and a -4.5 V power supply is used. The linearized transadmittance amplifier is a single-ended multitransistor circuit with passive feedback and single-pole stabilization. We report results for two versions: in mod1a the ECM current is set by a current mirror, while mod2a includes the 50 /spl Omega/-matched linearized amplifier, which consumes 150 mW total.