Millimeter wave experiment for ATS-F

A detailed description of spaceborne equipment is provided. The equipment consists of two transmitters radiating signals at 20 and 30 GHz from either U.S. coverage horn antennas or a narrow beam parabolic antenna. Three modes of operation are provided: a continuous wave mode, a multitone mode in which nine spectral lines having 180 MHz separation and spaced symmetrically about each carrier, and a communications mode in which communications signals from the main spacecraft transponder are modulated on the two carriers. Detailed performance attained in the flight/prototype model of the equipment is presented both under laboratory conditions and under environmental extremes. Provisions made for ensuring reliability in space operation are described. Also described the bench test equipment developed for use with the experiment, and a summary of the new technology is included

Avionics system design for high energy fields: A guide for the designer and airworthiness specialist

Because of the significant differences in transient susceptibility, the use of digital electronics in flight critical systems, and the reduced shielding effects of composite materials, there is a definite need to define pracitices which will minimize electromagnetic susceptibility, to investigate the operational environment, and to develop appropriate testing methods for flight critical systems. The design practices which will lead to reduced electromagnetic susceptibility of avionics systems in high energy fields is described. The levels of emission that can be anticipated from generic digital devices. It is assumed that as data processing equipment becomes an ever larger part of the avionics package, the construction methods of the data processing industry will increasingly carry over into aircraft. In Appendix 1 tentative revisions to RTCA DO-160B, Environmental Conditions and Test Procedures for Airborne Equipment, are presented. These revisions are intended to safeguard flight critical systems from the effects of high energy electromagnetic fields. A very extensive and useful bibliography on both electromagnetic compatibility and avionics issues is included

SPATIAL LOCATION OF ELECTROSTATIC DISCHARGE EVENTS WITHIN INFORMATION TECHNOLOGY EQUIPMENT

In this thesis, a system to locate an electrostatic discharge (ESD) event within an electronic device has been developed. ESD can cause a device to fail legally required radiated emissions limits as well as disrupt intended operation. The system used a fast oscilloscope with four channels, each channel attached to a high frequency near-field antenna. These antennas were placed at known locations in three dimensional space to measure the fields radiated from the ESD event. A Time-Difference-of-Arrival technique was used to calculate the location of the ESD event. Quick determination of the ESD event location provides developers with a tool that saves them time and money by eliminating the time-consuming and tedious method of general ESD mitigation within a product

Aircraft takeoff performance monitoring in far-northern regions : an application of the global positioning system

A design approach for an aircraft takeoff performance monitoring system (TOPMS) is described. In this approach, it is proposed that the Global Positioning System (GPS) in conjunction with a discrete Kalman Filter be used to determine aircraft acceleration, ground speed, and position relative to the end of the runway. A practical evaluation of the feasibility of this proposal showed clear superiority of a GPS-derived acceleration over a more traditional method employing accelerometers. This study found that, when compared to observations from carefully mounted accelerometers, the GPS-derived observation agreed to within 0.10 metres per second squared ninety percent of the time. Advantages of the GPS-derived observation included a modest noise level, insusceptibility to gravity and temperature-influenced variations, and far simplified mounting criteria. A theoretical dynamic model of an aircraft in contact with the ground was developed in consideration of factors pertaining to runways at far-northern Canadian airports. In the model, factors such as runway slope, wind velocity, wheel friction coefficient, and aircraft control settings were considered constant. While variability in any parameter considered constant by the model could influence the performance of a TOPMS, such variability was deemed beyond the scope of this preliminary investigation of a TOPMS designed specifically for the far-northern environment. A device containing a GPS receiver and data acquisition system was designed and certified, then installed in an aircraft operated by an airline servicing far-northern Canadian airports. The data collected in this manner were used to validate the theoretical model. It was concluded that a projection of displacement can be determined to within an uncertainty of fifteen metres in sufficient time to alert the pilot of an unsafe situation

Microwave reflectometer ionization sensor

The development of the Microwave Reflectometer Ionization Sensor (MRIS) Instrument for use on the Aeroassist Flight Experiment (AFE) spacecraft is described. The instrument contract was terminated, due to cancellation of the AFE program, subsequent to testing of an engineering development model. The MRIS, a four-frequency reflectometer, was designed for the detection and location of critical electron density levels in spacecraft reentry plasmas. The instrument would sample the relative magnitude and phase of reflected signals at discrete frequency steps across 4 GHz bandwidths centered at four frequencies: 20, 44, 95, and 140 GHz. The sampled data would be stored for later processing to calculate the distance from the spacecraft surface to the critical electron densities versus time. Four stepped PM CW transmitter receivers were located behind the thermal protection system of the spacecraft with horn antennas radiating and receiving through an insulating tile. Techniques were developed to deal with interference, including multiple reflections and resonance effects, resulting from the antenna configuration and operating environment

Long-term effects of thermal variation on the performance of Balanced Twisted Pair Cabling

Remote powering over the Ethernet (including PoE, PoE+ and PoE++) is currently trending as a cost-effective option to power networked devices using balanced twisted pair cabling. As technology advances and Ethernet penetration grows, more devices are deployed, thereby increasing the cabling density to support these devices. Power delivery through Ethernet cables has numerous benefits, including cost and space saving. However, concurrent high-power transmission and installation conditions could induce local heating, and thus, thermal variation may occur in the cable bundles, and these can be exacerbated by the installation conditions, and sometimes by extreme weather conditions. Over a long time, all these could modify the cable properties, thus affecting the performance of the cabling system and thereby impacting the Ethernet signal integrity. Although Joule heating of the cable bundle is primarily assumed to be concomitants of current transmission through the cable, several fundamental questions around these processes are not yet fully answered. They include: Do cable heating and thermal variations influence the designed transmission parameters of the cable? If yes, how can the cause(s) and effects be accurately measured and reliably validated? In answering some of these questions, a series of experiments were developed and adopted to (1) assess cable bundle heating (2) assess the performance of Balanced Twisted Pair cables subject to repeated thermal variation, both within the specified operating range and beyond to account for the situations where high temperature and localised heating might stress the cables beyond the designed or expected levels (3) assess the performance of Ethernet cable dielectrics to understand some of the root causes of Ethernet cable performance degradation. The outcome of the research showed that high power (100 watts) deployment over bundled and insulated unshielded Ethernet cables triggered an extremely high-temperature increase (~ 1400C) that resulted in mechanical failure of the cables’ dielectrics and a short circuit between the copper conductors of the cables. Larger cable conductor size, screening of the twisted pair along with Fluoropolymers as the conductor insulation helped the shielded cables not to reach a point of failure when tested in the insulated environments and at high power levels even though there was a temperature rise on the cables. Moreover, repeated resistive and non- resistive heating have adverse effects on the electrical properties and transmission parameters of Balanced Twisted Pair cables, most notably in the first few cycles. The impact was more pronounced during the cooling phase than the heating phase. Also, the thermal impact was more accentuated in insulated operating condition than in ventilated operating condition. The electrical length of the cable measured by the tester decreased by 0.7 m 5 due to the effect of repeated non-resistive heating in an insulated environment and at a high temperature of ~1200C but decreased by 0.4 m with ~700C in a similar insulated environment. Phase drifts in Balanced Twisted Pair cables were observed to be dependent on the combined effects of mechanical dimension, dielectric constant and frequency. Thermal variation caused a phase change in the Return Loss (RL) signal from 630 to 900, from 900 to 1350 and from 1350 to 3150 respectively. The RL performance of Category 6 U/UTP CoMmunications Plenum rated (CMP) cable failed at 200C and recovered at 230C initially, but after the electrical length of the cable had decreased, subsequent failure and recovery temperatures accelerated towards higher temperature (400C). Similarly, the transition temperatures of the bandwidth of the cavity loaded with the Fluorinated Ethylene Propylene (FEP) from the Category 6 U/UTP CMP cable accelerated during the prolonged thermal cycling. The maximum reduction in the RL value of Category 6A F/UTP cable due to the 40 thermal cycles conducted was observed to be 5 % per degree, whereas the maximum Insertion Loss (IL) increase was 5.8 % per degree. Moreover, for the 24 thermal cycles conducted on Category 6 U/UTP CMP cable, an increase in IL of ~8.3 % per degree was observed while RL decreased by ~6.8 % per degree. Using the Features Selective Validation technique, the comparison between the baseline performance and long-term performance of Category 6A F/UTP permanent link (PL) showed a fair agreement, which implies degradation in the performance of the cable. Furthermore, results showed that impedance varied significantly along the length of the cable due to localised heating of the cable. The impedance along the unheated sides of the cable reverted at every 2 (0.4 m) and 4 (0.2 m) but the impedance profile of the heated middle portion of the cable varied significantly. The results of the Scanning Electron Microscope revealed the deformation in the conductor insulation of a twisted pair sample. Furthermore, the adhesion of the twisted pair conductor insulation to its copper conductor was also observed to be affected near the end of the twisted pair sample. Connector impedance mismatch was observed to be severe on the split pair pins (pair 3,6) than other pairs in the cable. The connector impedance mismatch also dominated the Near End Crosstalk (NEXT) loss at frequencies around 35 MHz. The repeated heating of the cable to a higher temperature of 1200C caused the loss of the PL at room temperature and a DC contact resistance issue which of course resulted in poor intra-pair resistance unbalance between the split pair. The Transverse Conversion Loss (TCL) and Equal Level Transverse Conversion Transfer Loss (ELTCTL) of Category 6 U/UTP CMP PL revealed some imbalances in the structure of the twisted pairs. Also, the equivalent differential mode noise voltages for the TCL values of the cable revealed a voltage spike following the decrease in the electrical length of the cable. More also, Crosstalk performance between the longest and shortest pair in the Category 6A 6 F/UTP cable was also observed to be better due to the heating of the cable in comparison to the crosstalk loss measured due to the cooling of the cable. Crosstalk performance of the portion insulated cables was initially worse during the first few heating and cooling cycles but improved afterwards. In addition, crosstalk, which was not initially present at the reference plane of the permanent link, was observed to increase rapidly from the point where the electrical length decreased. The increase in temperature to ~650C caused an accentuated frequency shift in the resonance of the FEP, which is the probable cause of the immediate performance degradation of the Category 6 U/UTP CMP cable. The dielectric constant of the extracted FEP rod sample from Category 6 U/UTP CMP cable increased as a consequence of prolonged thermal cycling, particularly during the cooling phase, which also suggests the root cause of the poor RL performance observed during the cooling phase. The increased loss tangent of the FEP during thermal cycling also indicates that IL performance degradation of the Ethernet cables will increase during the heating and cooling process in Ethernet cables. Also, on a long-term, IL performance will drift due to thermal cycling. Furthermore, various signal phase transitions were recorded during the heating and cooling of the cable and its dielectric due to the different behaviour of the molecular transitions. As a result, an echo of RL was measured during the transition between the intermittent and prolonged thermal cycling of the cable, of which can be correlated to the spurious resonance, observed in the resonance of the FEP sample during the transition period. Thus, it could be inferred that immediate and longterm effects of thermal variation influence the designed electrical properties and transmission parameters of Balanced Twisted Pair cables. Also, an immediate and long-term effect of thermal variation on the conductor insulation of the cable has a direct effect on the performance of Balanced Twisted Pair Cables

Gateway Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment

This document is a tailored version of MIL-STD-461, Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment, for the Gateway Program. While many of the requirements contained herein correspond with a MIL-STD-461 requirement, some are unique to the Gateway Program in order to meet the specific needs of the program. Nearly all limits are tailored specifically for Gateway elements, systems, and subsystems

Power system applications of fiber optics

Power system applications of optical systems, primarily using fiber optics, are reviewed. The first section reviews fibers as components of communication systems. The second section deals with fiber sensors for power systems, reviewing the many ways light sources and fibers can be combined to make measurements. Methods of measuring electric field gradient are discussed. Optical data processing is the subject of the third section, which begins by reviewing some widely different examples and concludes by outlining some potential applications in power systems: fault location in transformers, optical switching for light fired thyristors and fault detection based on the inherent symmetry of most power apparatus. The fourth and final section is concerned with using optical fibers to transmit power to electric equipment in a high voltage situation, potentially replacing expensive high voltage low power transformers. JPL has designed small photodiodes specifically for this purpose, and fabricated and tested several samples. This work is described

Ranger tv subsystem /block iii/. volume 4b- appendices

Component reliability and failure analysis of Ranger television subsyste

Aircraft electromagnetic compatibility

Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting