Browse Topic: Audio equipment

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Verifying large alternate product code for an JA GV document - JA1124XXJA1224XX/NEW/00000000000000000001_202511 (Current)11/24/2025
Verifying large alternate product code for an JA GV document - JA1124XX
Active Safety Systems Standards Committee
Overview of a Comprehensive MD530F Acoustic Flight TestF-0081-2025-00245/20/2025
A cooperative flight test campaign between the US Army and NASA was performed. This test sought to characterize the acoustic emissions of a fully instrumented MD530F helicopter using a snapshot array and a phased array of microphones. The snapshot array of microphones aimed to provide even coverage across the surface of a hemisphere, providing an acoustic emission hemisphere in a single 'snapshot' of time. The phased array of microphones was designed to provide enough resolution to determine noise sources from each individual blade as well as perform source separation from main rotor and tail rotor emissions. Test conditions for the characterization effort were chosen using a traditional one-factor-at-a-time approach as well as three design of experiment approaches. Characterization conditions included constant speed level flight, descent, and ascent conditions. Transient maneuver conditions were also captured over the snapshot array. The vehicle instrumentation included measurements
Stephenson, James, Pascioni, Kyle, Houston, Mary, Stutz, Colin, Preston, Martin
Frequency Domain gappy-POD for Rotor Acoustic Measurement OptimizationF-0080-2024-11215/7/2024
This paper describes a mathematical framework for determining the optimal sensor set location for adequately capturing the sound generated by rotors. The approach leverages the gappy-POD method proposed by Everson and Sirovich [J. Opt. Soc. Am., Vol. 12, 1995, pp. 1657-1664], which first identifies the various mode constituents that make up the first few rotor blade-pass frequency harmonics of the sound-field. The algorithm is developed using a covariance matrix for the POD problem comprising auto- and cross-spectral densities of spatially and temporally resolved sound waves captured by an array of microphones oriented parallel to the axis of a laboratory-scale hovering rotor. Three different forms of the technique are developed and compared. These comprise a homogeneous form and two heterogeneous forms; the heterogeneous forms are referred to as XX-topos and XX-chronos and depends on which term in the error minimization equation is assigned the gappy sensor set. A greedy algorithm is
Tinney, Charles, Valdez, John, Zhao-Dubuc, Irene
Characterize the Sound Field Generated from a Vehicle Horn by Pellicular Analysis2025-01-00585/5/2023
To predict the sound field produced by a vehicle horn requires a good source representation of it in the full vehicle model. This paper investigates the characterization of a physical vehicle horn by an inverse method called pellicular analysis. To implement this method, firstly an acoustic testing is performed to measure the sound pressure radiated from the horn at a certain number of microphone locations in a free field environment. Based on the geometry of a virtual horn, the locations of each microphone and measured sound pressure data, pellicular analysis is adopted to recover a set of vibration pattern of the virtual horn. The virtual horn and the recovered vibration information are then incorporated in a full vehicle numerical model to simulate its exterior sound field. The validity of this approach is confirmed by comparing the prediction for a horn in a production vehicle to the corresponding physical test which is required to meet the Brazilian regulation CONTRAN 764/2018.
Yang, Wenlong, MELO, ANDRE
Localisation of Ultra-short Sound Emissions from Automotive Components by Using the Sound Field Scanning Method2025-01-00925/5/2023
Design verification and quality control of automotive components require the analysis of the source location of ultra-short sound events, for instance the engaging event of an electromechanical clutch or the clicking noise of the aluminium frame of a passenger car seat under vibration. State-of-the-art acoustic cameras allow for a frame rate of about 100 acoustic images per second. Considering that most of the sound events introduced above can be far less than 10ms, an acoustic image generated at this rate resembles an hard-to-interpret overlay of multiple sources on the structure under test along with reflections from the surrounding test environment. This contribution introduces a novel method for visualizing impulse-like sound emissions from automotive components at 10x the frame rate of traditional acoustic cameras. A time resolution of less than 1ms eventually allows for the true localization of the initial and subsequent sound events as well as a clear separation of direct from
Rittenschober, Thomas
Active Control of Engine Order Noise for Heavy-duty Trucks: Using the Genetic Algorithm for the Optimization of Error Microphone Arrangement2025-01-00135/5/2023
The arrangement of error microphones for a vehicle active noise control (ANC) system is no trivial work, especially for heavy-duty trucks due to the dilemma resulted from the large volume of the cab and the limited number of microphones accepted by most manufacturers in the auto industry. Most ANC developers resort to trial and error, which is not only a heavy workload given the amount of interested working conditions to be test, but also does not guarantee to yield the optimum noise cancellation performance. In this paper, the authors proposed an error microphone selection methodology using a genetic-algorithm (GA) -based mechanism. The target vehicle was a heavy-duty truck with a six-piston diesel engine, and two scenarios were particularly interested, i.e. driver & copilot and driver & one passenger sleeping on the berth. We first arranged eight microphones at different locations in the cab, five on the headrests, two on the B pillars and one at the head position of the sleeping
Wang PhD, Jian, Ling, Zihong, Zhang, Zhe, Cai, DeHua, lv, Xiao, Zhang, Ming, Gao, GuoRan
Excavator exterior noise contribution analysis using angle-based operational acoustic load synthesis.2025-01-00625/5/2023
Since earth moving machines (EMM) are subject to exterior noise (EN) regulations, OEMs need to develop mitigation solutions from an early design stage. It is challenging to predict solution effectiveness at early design stage. Excavators are distinct compared to other EMM as their upper frame rotate while keeping lower frame fixed. ISO 6395(2) or EC/2000/14(1) require EMMs to follow specific operating maneuvers where noise sources change their position, directivity, and speed along the operating cycle. These conditions pose challenges in performing noise contribution analysis as a function of angular position and operating condition. Authors successfully demonstrated Acoustic source quantification and contribution analysis for linearly moving EMMs. However, excavator pose data processing challenges due to angular motion. This work demonstrates the use of frequency domain ASQ for operational acoustic source quantification and use of frequency domain virtual prototype sub structuring
Vesikar, Prasad Balkrishna, Haynes, Timothy, Aquino Arriaga, Adrian Antonio, Drabison II, John, Chaduvula, Prasanna
Comprehensive EV Sound Design project from Marketing Requirements to Series2025-01-00185/5/2023
This paper presents the results of a project to design new comprehensive sound sets for several electric vehicle models having each specific branding expectations. This was achieved thanks to a close collaboration between one major Chinese electric vehicle manufacturer and an acoustic software provider, relying on shared experience, knowledge, and tools to meet the initial requirements set. Firstly, a scenarized journey and brand-related symbolism were defined and served as a basis for creating meaningful sketches of sound design in a cross-team effort (designers, NVH, production, audio system, etc.). Various sound functions were considered for exterior sounds, such as AVAS, and interior sounds, such as ambiance, HMI, and alarms. A special care was dedicated to the so-called Active Sound Design aiming at providing speed and acceleration feedback to the driver, in the absence of a clearly audible engine noise. A listening test was then conducted in order to assess how the proposed
LI, Yanhao, Minard, Antoine, Boussard, Patrick, Zhang, Charles
A novel framework for accelerating EDU NVH simulation using scalable transfer functions and evaluating manufacturing defects through space order excitation2025-01-00445/5/2023
In the ultra-luxury vehicle segment, achieving optimal NVH (Noise, Vibration, and Harshness) performance across a growing range of load cases in drive and regeneration conditions presents significant engineering challenges. As the complexity of load cases escalates with varying torque ripple and transmission errors, traditional time and frequency-domain simulations become computationally inefficient. To address these challenges, an in-house software framework that employs Noise Transfer Functions (NTFs) and Vibration Transfer Functions (VTFs) is developed. The system’s dynamic response is computed once and scaled to various excitation sources, which includes radial and tangential forces derived from EMAG simulations, and gear forces derived from MBS simulation. Speed sweep simulation is performed to systematically characterize the RPM range, allowing for precise scaling of the transfer function against the original forces to obtain the responses in mounts or microphones. The resulting
Sureshkumar, Sanjai, Shaw, Stephen, Qureshi, Manucher, Duclaux de L'Estoille, Nicolas
A Study on the Subwoofer Rattle Noise Analysis and System Target Setting2025-01-00905/5/2023
Rattle noise from electrical sound systems is becoming one of the prominent issues for automakers as it directly affects the perception of customers about vehicle quality. Recent times, quality sound system is prerequisite for automotive passenger vehicles. And, in the whole sound systems subwoofer forms dominant part of sound output. However, sub-woofer rattle noise problem sometimes occurs in small and midsize SUV. Generally, sub woofers are located inside rear quarter area (back side of the quarter panel), due to the limitation in the available space. Mainly rattle is noise resulting from physical impact of two parts due to vibrations when relative displacement is bigger than gap of two parts, it occurred in 50-100Hz, which is main excitation range of sub-woofer. In this study, we analyze the sub-woofer structural vibration analysis for five sample vehicles based on the test and correlation. However, the present sub-woofer system model has limitation in determining the level of this
Thota, Jagadeesh, Choi, Seungchan, Park, Jong-Suh
Method for Performing Indirect Lightning Test Simulation2022-26-11825/26/2022
From the statistics it has been observed that major qualification test failures in aerospace system are from lightning tests. These failures lead to major cost and schedule implications as fixing these issues later in the design usually requires a product re-spin. To avoid such failures, testing of critical interfaces using simulation allows engineers to investigate the behavior of the product/system in different scenarios and visualize the effect of these changes at an earlier stage in the design. Achieving this through simulation also eliminates the need of heavy costs associated with physical prototyping & testing. The existing simulation techniques use prebuilt & formula-based lightning waveform models and also do not take into consideration the end to end impedance characteristics like cable impedance, remote impedance, etc. With these available techniques, achieving results closer to practical scenarios is difficult. To overcome some of these challenges, this paper presents a
Rajeurs, Ajaypal, Gouda, Vidyadhar
Identification of Low-Frequency/Low SNR Automobile Noise Sources2021-01-10628/31/2021
This paper presents experimental investigations of determining and analyzing low-frequency, low-SNR (Signal to Noise Ratio) noise sources of an automobile by using a new technology known as Sound Viewer. Such a task is typically very difficult to do especially at low or even negative SNR. The underlying principles behind the Sound Viewer technology consists of a passive SODAR (Sonic Detection And Ranging) and HELS (Helmholtz Equation Least Squares) method. The former enables one to determine the precise locations of multiple sound sources in 3D space simultaneously over the entire frequency range consistent with a measurement microphone in non-ideal environment, where there are random background noise and unknown interfering signals. The latter enables one to reconstruct all acoustic quantities such as the acoustic pressure, acoustic intensity, time-averaged acoustic power, radiation patterns, etc. By combining a passive SODAR and modified HELS methods, engineers will be able to
Lu, Yazhong, Wu, Sean, Yuan, Zeyu, He, Wen, Li, Zhaoting, Li, Huijun
Study of the Effects of Active Noise Cancellation on Music Playback2021-01-10168/31/2021
Technology for automotive active noise cancellation (ANC) such as HARMAN’s Engine Order Cancellation (EOC) system help reduce in-cabin noise levels using a set of error microphones and the vehicle’s built-in audio system to generate anti-noise signals. A major benefit of these systems is that significant reduction in unwanted noise levels in the 20 - 400 Hz range can be achieved without the addition of extra noise control material. However, in the instances where the frequencies of anti-noise signals and music signals overlap, a degradation in the overall music reproduction quality is possible. In this paper, we study the effects of EOC on music playback by applying signal processing and statistical methods to objectively measure degradation in audio content when EOC is active. This study is carried out using production EOC software in a simulation environment. The simulation models the cabin acoustic response from measured vehicles and uses recordings of vehicle noise and music as
Basu, Sattwik, Tackett, Jeffrey, Trumpy, David, Walt, Adam, Adari, Santosh
Cost-Effective Day & Night Marking Using LasersTBMG-386283/1/2021
“Day & night marking” is used in automobiles, aviation, instrumentation and computer keyboards to make buttons and controls (e.g. door locks, window controls, sound system adjustments, etc.) clearly visible under ambient illumination conditions varying from bright sunlight (day) to low light (night). Although it sounds simple, manufacturing these products cost-effectively in a small-batch production environment requires the use of a sophisticated, automated, laser-based tool.
Processor Power and Energy EfficiencyTBMG-383481/1/2021
Think about what your cellphone was like 15 years ago. Most likely, it could be used only for telephone calls — no texting, no photos, no videos, and no music. Think about your business trips then with your carry-on bag crammed with a camera, a portable CD player, a travel alarm, maybe a GPS, possibly a tape recorder, a day planner, a calculator, and more.
Wiegand Wire: Energy Harvesting and MoreTBMG-373878/1/2020
The “Wiegand effect” was discovered more than 40 years ago and while it has been used successfully in several specialized applications, its full potential for energy harvesting and signal generation has received only limited recognition. With enhancements to the energy output from Wiegand devices and the emergence of a new generation of ultra-efficient electronic chips, the technology is showing significant promise, especially in the exciting area of the Industrial Internet of Things (IIoT).
3D Audio Reproduction via Headrest equipped with Loudspeakers – Investigations on Acoustical Design Criteria2020-01-15676/3/2020
This paper focuses on the analysis and evaluation of acoustical design criteria to produce a plausible 3D sound field solely via headrest with integrated loudspeakers at the driver/passenger seats in the car cabin. Existing audio systems in cars utilize several distributed loudspeakers to support passengers with sound. Such configurations suffer from individual 3D audio information at each position. Therefore, we present a convincing minimal setup focusing sound solely at the passenger’s ears. The design itself plays a critical role for the optimal reproduction and control of a sound field for a specific 3D audio application. Moreover, the design facilitates the 3D audio reproduction of common channel-based, scene-based, and object-based audio formats. In addition, 3D audio reproduction enables to represent warnings regarding monitoring of the vehicle status (e.g.: seat belts, direction indicator, open doors, luggage compartment) in spatial accordance. Furthermore, individual sound
Brandner, Manuel, Hatheier, Thomas, Sontacchi, Alois
5 Ws of PAWS Smart HeadphonesTBMG-361993/1/2020
Pedestrians who wear headphones or earbuds to listen to music, text, or talk on smartphones while walking, putting themselves at risk by tuning out the traffic around them.
5 Ws of EarEchoTBMG-3569312/1/2019
Anyone who uses a smartphone with in-ear earphones.
3D Printing: SLS Creates New Potential for Design in Medical TechnologyTBMG-3536610/1/2019
Laser sintering technology enables medical technology designers to print plastic objects for feasibility studies within a very short time. The functional prototypes largely have the same properties as injection-molded parts. EEM AG goes one step further: It manages a balancing act between the production of prototypes and small series.
Design and Validation of Low-Cost Intensity Probe2019-01-14626/5/2019
Sound intensity measurement techniques that used a two-microphone configuration, were first developed in the late 1970s. Originally, the focus was on improving precision during testing or post-processing. However, with the advent of modern, sophisticated equipment, the focus has shifted to the apparatus. Availability of phase-matched microphones has made post-test correction obsolete as the microphones eliminate a majority of the errors before the data is even collected. This accuracy, however, comes at a cost, as phase-matched microphones are highly priced. This paper discusses employing the method of improving post-processing precision, using inexpensive, current equipment. The phase error of the system is corrected using a simple calibration technique and a handheld phase calibrator that is similar to the one used for amplitude calibration of microphones. The intensity probe and calibrator is manufactured using rapid prototyping and the executable software that goes with the probe
Gundre, Karan, Barnard, Andrew
Full-Spectrum Infrasonic Stethoscope for Screening Heart, Carotid Artery, and Lung-Related DiseasesTBMG-346196/1/2019
Microphones and stethoscopes are regularly used by physicians to detect sounds when monitoring physiological conditions. These monitors are coupled directly to a person's body and measure in certain bandwidths either by listening or by recording the signals. The physiological processes, such as respiration and cardiac activity, are reflected in a different frequency bandwidth from 0.01 Hz to 500 Hz.
Acoustic Testing of the Tiltrotor Test Rig in the National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind TunnelF-0075-2019-144505/13/2019
The Tiltrotor Test Rig (TTR) was tested in the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel from 2017 to 2018. The primary goal of the test was to understand the operational capabilities of the TTR, while also acquiring research data, including acoustic data. Four microphones were placed around the TTR: two on the wind tunnel floor and two on struts. Acoustic measurements of the TTR rotor were acquired to 1) understand the acoustic testing capabilities of the TTR in the NFAC 40- by 80-FootWind Tunnel, 2) compare to previous XV-15 rotor acoustic data acquired in the NFAC 80- by 120-Foot Wind Tunnel, and 3) provide data for future validation studies. A data quality study revealed that the NFAC 40- by 80-Foot Wind Tunnel is an adequate acoustic environment to test the TTR rotor. For a given thrust and advance ratio, a shaft angle sweep was performed and acoustic measurements were compared against 1996 and 1999 XV-15 data in the NFAC 80- by 120-Foot Wind
Schatzman, Natasha, Malpica, Carlos
Effect of Pitch Attitude on the Performance and Acoustics of a Lift-Offset Coaxial Rotor Based on High-Fidelity CFD/CSD SimulationsF-0075-2019-144515/13/2019
This paper investigates the effect of pitch attitude on both performance and acoustics of a lift-offset coaxial rotor based on a first-principles and high-fidelity CFD/CSD loose coupling approach at 150 and 200 knots. The pitch attitudes selected for this research are -5° , 0° , and 5° . The CFD/CSD loose coupling simulations are carried out using the CREATETM -AV software Helios while the coaxial rotor acoustics is simulated using PSU-WOPWOP at eight microphones positioned below the lower rotor. A detailed aerodynamic analysis is performed at 150 knots. A total of six major aerodynamic interactions are identified: 1) hub-wake interaction, 2) self-BVI, 3) parallel rotor-to-rotor BVI, 4) blade-crossover events, 5) root-induced BVI, and 6) reversed-flow- edge-vortex interactions. The strength of these interactions is dependent on the vehicle pitch attitude. The cases with negative pitch attitude show significantly stronger impulsive pressure pulses, which is found to be induced by
Jia, Zhongqi, Sharma, Kalki, Lee, Seongkyu, Brentner, Kenneth
Acoustic Waves Offer Treatment for Kidney StonesTBMG-3324511/1/2018
Researchers are investigating the use of time reversal (TR) signal processing to focus waves sound with high amplitudes in a room. In biomedical applications, focused ultrasound can be used in lithotripsy procedures for treating kidney stones or to target brain tumors.
Ultra-Thin Capacitive Sensor Has the Least Possible Resistance to MotionTBMG-324688/1/2018
A thin and flexible sensor was developed for sensing sounds, since it can move with the airflow made by even the softest noises. With the least possible resistance to motion, the sensor addresses issues with accelerometers, microphones, and many other similar sensors. The goal was to create a sensor that only resists gravity. It needs to stay connected to the device, but otherwise needed to move with even the slightest sounds or air movement. Being able to move with the air is how sensors are able to tell when a sound is present and from which direction it is coming.
Automating Personal Safety with Wearable Smart JewelryTBMG-290126/1/2018
A major challenge to assault prevention is that during an assault, victims often do not have an easily accessible way to call for help. Whether calling 911 or using an emergency alert app or device, the user has to press a button in order to call for help. That is often not possible while a violent act is taking place or if a person is unconscious as a result of the assault.
Stretchable Electronics a ‘Game Changer’ for Stroke Recovery TreatmentTBMG-287454/1/2018
A groundbreaking new wearable device designed to be worn on the throat could be a game changer in the field of stroke rehabilitation.
Sound Inaudible to Humans Can Be Recorded by MicrophonesTBMG-287024/1/2018
Microphones, from those in smartphones to hearing aids, are built specifically to hear the human voice — humans can’t hear at levels higher than 20 kHz, and microphones max out at around 24 kHz, meaning that microphones only capture the sound humans hear.
Paper-Thin Device Acts as a Loudspeaker and MicrophoneTBMG-2802612/1/2017
A paper-thin, flexible device was created that can generate energy from human motion, and can act as a loudspeaker and microphone. The transducer is ultrathin, flexible, scalable, and bidirectional, meaning it can convert mechanical energy to electrical energy, and vice-versa.
MEMS Move Wearables Beyond Touch InterfacesTBMG-270186/1/2017
We use touch, the dominant user interface for years, to tap keyboards on laptops and tablets, to communicate with our car’s portable GPS, and to text friends and take photos from our smartphones.
Statistical Characterization, Pattern Identification, and Analysis of Big Data2017-01-02363/28/2017
In the Big Data era, the capability in statistical and probabilistic data characterization, data pattern identification, data modeling and analysis is critical to understand the data, to find the trends in the data, and to make better use of the data. In this paper the fundamental probability concepts and several commonly used probabilistic distribution functions, such as the Weibull for spectrum events and the Pareto for extreme/rare events, are described first. An event quadrant is subsequently established based on the commonality/rarity and impact/effect of the probabilistic events. Level of measurement, which is the key for quantitative measurement of the data, is also discussed based on the framework of probability. The damage density function, which is a measure of the relative damage contribution of each constituent is proposed. The new measure demonstrates its capability in distinguishing between the extreme/rare events and the spectrum events. Several case studies including
Wei, Zhigang, Nikbin, Kamran
PLCs Improve Control of Radio BroadcastsTBMG-264352/1/2017
Broadcasting employs the latest technology in many areas, but controlling the broadcast hardware connected to the antenna and the related transmission power, source, and facilities is usually still a low-tech operation. Typically, a broadcast engineer will drive to the unattended transmitter, translator, or repeater site to flip switches and make other manual adjustments (Figure 1).
Source Separations and Identification by Structural Holography2016-01-17996/15/2016
The source field reconstruction aims at identifying the excitation field measuring the response of the system. In Near-field Acoustic Holography, the response of the system (the radiated acoustic pressure) is measured on a hologram using a microphones array and the source field (the acoustic velocity field) is reconstructed with a back-propagation technique performed in the wave number domain. The objective of the present works is to use such a technique to reconstruct displacement field on the whole surface of a plate by measuring vibrations on a one-dimensional holograms. This task is much more difficult in the vibratory domain because of the complexity of the equation of motion of the structure. The method presented here and called "Structural Holography" is particularly interesting when a direct measurement of the velocity field is not possible. Moreover, Structural Holography decreases the number of measurements required to reconstruct the displacement field of the entire plate
Thomas, Jean-Hugh, Chesnais, Corentin, Totaro, Nicolas, Guyader, Jean-Louis
Smartwatches Can Now Track Your Finger in Mid-Air using sonarTBMG-243984/12/2016
As mobile and wearable devices such as smartwatches grow smaller, it gets tougher for people to interact with screens the size of a matchbook. That could change with a new sonar technology developed by University of Washington computer scientists and electrical engineers that allows you to interact with mobile devices by writing or gesturing on any nearby surface — a tabletop, a sheet of paper or even in mid-air.
CES rollouts extend connectivity, app integration16AUTP02_042/1/2016
The tightening links between autos and consumer electronics were in evidence at the 2016 Consumer Electronics Show in Las Vegas as several automakers and suppliers unveiled infotainment technologies. Connectivity and simplified app integration technologies were among the many transportation offerings at the monstrous show. Vendors throughout the industry unveiled connectivity products. An amplifier was among Harman's connectivity offerings. It uses a customized microcontroller to provide connectivity, noise cancellation, equalization, and surround sound. That trims size and complexity significantly.
Costlow, Terry
SAE U.K. SECTION CO-HOSTS LECTURE SERIES ‘STARRING’ NASA ENGINEER/ EXPERT16MOMP02_042/1/2016
Dr. Ravi Margasahayam of NASA is the engineer responsible for ensuring payload safety for the Space Shuttle and the International Space Station. The SAE United Kingdom Section recently collaborated with the Institution of Mechanical Engineers (IMechE) and the Institution of Engineering and Technology (IET) in the U.K. to arrange an extended lecture series by Dr. Ravi Margasahayam of NASA. He is the engineer responsible for ensuring payload safety for the Space Shuttle and the International Space Station (ISS). He has a background in acoustics and vibration, and has been with NASA for 25 years. Margasahayam provides talks on NASA activities internationally, something that Professor Bernard Challen (an SAE volunteer who lives in the U.K. and is active in various SAE meetings) discovered last June in Madison Wisc., when he heard him speak. What started as an intention to set up maybe three lectures in the U.K. developed into a series of nine meetings. By coincidence, the lecture tour
MARK 4 SELECTIVE CALLING (SELCAL)ARINC714A (Current)11/4/2015
This document represents a significant improvement to existing Selective Calling (SELCAL) standards used with HF and VHF voice communications. The goal is to eliminate the possibility that two or more aircraft could respond to the same radio call. The Mark 4 SELCAL system definition provides the following: " Guidance for integrated and federated audio systems " 32 audio tones total (16+16) yielding up to 215,760 unique codes " SELCAL form, fit, & function definition " Interwiring and installation details " Defines SELCAL decoding requirements in the presence of significant signal degradation.
Airlines Electronic Engineering Committee
Occupancy Rate Inside Motor Vehicles Using Wireless Sensors Networks2015-36-05499/22/2015
This work aims the implementation of a system able to estimate the occupancy rate (number of occupants) inside motor vehicles. This system is based on a Wireless Sensors Network using the standard IEEE 802.15.4, connected to a computer. The estimation of occupancy rate inside the motor vehicle can provide better energy efficiency and therefore optimize fuel and battery consumption.
Zacariotto, Wendler Augusto, Coiado, Lorenzo Campos, Barros, Daniel Braga, Mota, Lia Toledo Moreira, de Assis Mota, Alexandre
Sensing Device Separates Simultaneous SoundsTBMG-227808/19/2015
A new technology developed at Duke University uses metamaterials and compressive sensing to determine the direction of a sound and extract it from the surrounding background noise. Once miniaturized, the device could have applications in hearing aids, cochlear implants, and ultrasound medical sensors.
Improving Tube Sound Transmission Loss Measurements Using the Transfer Matrix Technique to Remove the Effect of Area Changes2015-01-23106/15/2015
The Sound Transmission Loss of automotive intake and exhaust components is commonly measured using the four microphone tube method per ASTM E2611 [1]. Often area adapters are used to match the component diameter to that of the tube apparatus. These area adapters affect the Sound Transmission Loss measurement, especially at very low frequencies. The use of the Transfer Matrix Technique to remove the effect of the area adapters is described. The improvements for step and cone area adapters are compared.
Green, Edward Ray
Current Status and Future Developments of ANC Systems2015-01-22236/15/2015
Active Noise Control (ANC) has long been seen as emerging technology. During recent years, however, it became popular in new vehicle and infotainment platforms within a broad range of OEMs. This paper summarizes the current status and lessons learned of production systems (as well as those entering production soon) and gives an outlook on how ANC and related technologies will integrate in future vehicles and audio/infotainment architectures.
Schirmacher, Rolf
Intelligent Flamefinder Detection and Alert SystemTBMG-220375/1/2015
While NASA facilities already use huge volumes of hydrogen as a propellant/fuel, many other federal and state programs across the country are looking at potentially expanding the use of hydrogen. There are, however, significant challenges associated with hydrogen use. These include a tendency to leak through seals (due to the very small size of the hydrogen atom) that ordinarily would efficiently stop most other materials, a very high diffusion rate, a huge explosive mixture range, and the fact that hydrogen burns with an invisible flame. Therefore, hydrogen leak detection is an important capability associated with a safe and operational work environment for NASA facilities, as well as at any other location/site that would potentially use this fuel. At the time of this reporting, there is not a technology that provides simple, inexpensive, and wide-coverage methods that enable large quantities of hydrogen to be monitored. Sensors that are available tend to be limited to either a very
Microphones and Accelerometer Sensors Network for Acoustic Diagnostics (MASNAD)TBMG-217624/1/2015
A system has been developed using sound to detect problems on rovers or other remote platforms autonomously. It consists of a sensor array of microphones and accelerometers that uses the differences in the sounds generated by the motors, gears, instruments, or other devices being monitored to determine abnormal operation conditions.
Magnetic Fluids Deliver Better Speaker Sound QualityTBMG-217854/1/2015
In the early 1960s, NASA scientists were trying to move fuel into an engine without the benefit of gravity. A scientist at Lewis Research Center (now Glenn Research Center) came up with the idea to magnetize the liquid with extremely fine particles of iron oxide. That way, fuel could be drawn into the engine using magnetic force.
Virtualization for automotive IVI systems14MEIP09_039/1/2014
As the demand for modern in-vehicle infotainment systems grows, automakers are increasingly looking toward virtualization as a solution to bridge the gap between consumer and automotive electronics. In the past, automotive audio systems were characterized by simple functionality, a simple tuner, minimal user interface, and little to no two-way communication channels. They were also closed, in the sense that all of the software was loaded pre-sale by the manufacturer and normally remained unchanged for the lifetime of the device. The amount of software was small. Many modern in-vehicle infotainment (IVI) systems, however, are very different. Today's systems have sophisticated user interfaces, consisting of input keys or a touch screen, rearview cameras, audio, and high-resolution video outputs. Additionally, they combine many functions, including voice and data communication, productivity tools, media players, and games. They also support different wireless communication modes
Saminathan, V., Swaminathan, G.
Speech Acquisition and Automatic Speech Recognition for Integrated Spacesuit Audio Systems, Version IITBMG-199196/1/2014
Astronauts suffer from poor dexterity of their hands due to the clumsy spacesuit gloves during Extravehicular Activity (EVA) operations, and NASA has had a widely recognized but unmet need for novel human-machine interface technologies to facilitate data entry, communications, and robots or intelligent systems control. A speech interface driven by an astronaut’s own voice is ideal for EVA operations, since speech is the most natural, flexible, efficient, and economical form of human communication and information exchange.
“Ascent - Commemorating Shuttle” — A NASA Film and Multimedia Project DVDTBMG-199226/1/2014
NASA seeks to preserve, and make readily accessible, historical Space Shuttle launch footage to inspire and educate NASA stakeholders both in and outside the NASA family through the dissemination of the Ascent production materials as a DVD, and through both NASA Television and online social media avenues without incurring distribution and media costs.
Segment-wise Measurement of Helicopter Approach Noise with a Reduced Microphone SetupF-0070-2014-94185/20/2014
In order to measure the noise footprint of a helicopter approach procedure, microphones are usually distributed over a large area. In this paper, however, a method is utilized where the measurement of the noise footprint is conducted in parts by distributing the microphones over a limited area and executing the same approach procedure, while the position of landing point is shifted. The flight tests are conducted with the EC135-ACT/FHS helicopter. Guidance to the pilots is provided by use of a "Tunnel-in-the-Sky" head down pilot display. Since the same flight procedure is executed multiple times it is possible to conduct a statistical analysis on the accuracy and reproducibility of the approach procedure in terms of position, velocity and generated noise. This statistical analysis shows that the geometric accuracy is in the order of 6 meters in the horizontal plane and 12 meters in the vertical plane. The variations in the measured sound exposure level from one approach to another are
Frederic, Willem, Gursky, Bianca
Sample-Rate Conversion for Non-Clocked Audio Sources2014-01-02614/1/2014
In a connected vehicle, digital audio content may arrive at the audio system from sources that provide packets of audio samples with no associated sample clock. A common example is streamed internet audio. To process and play these sources, the audio system must first convert the audio stream so that it is compatible with the system's sample clock. Traditional sample-rate conversion methods are typically not capable of doing this. This paper presents and compares approaches for performing the conversion.
Whikehart, Bill
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