Sub-array equalization technique for the parametric array loudspeaker to reduce nonlinear distortion

2021 ◽  
Vol 263 (5) ◽  
pp. 1497-1504
Author(s):  
Chi Zhang ◽  
Jing Ren ◽  
Chuang Shi
Keyword(s):  
Nonlinear Distortion ◽  
Ultrasonic Transducer ◽  
Previous Method ◽  
Ultrasonic Transducers ◽  
Acoustic Effect ◽  
The Past ◽  
Comparison Results ◽  
Equalization Technique ◽  
Nonlinear Acoustic ◽  
Parametric Array

The parametric array loudspeaker (PAL) is a directional loudspeaker which uses the nonlinear acoustic effect, namely the parametric array, to produce an audio beam from narrow ultrasonic beams. The PAL can efficiently deliver audible information, without generating noise to the surroundings. One significant drawback of the PAL is the nonlinear distortion. Therefore, many sophisticated methods have been proposed to preprocess the input signal of the PAL. However, those methods usually request a flat frequency response of the ultrasonic transducer array (UTA). In the past, equalization has been tried out for the whole UTA, but the performance was sometimes not satisfactory due to the inconsistent productions of ultrasonic transducers. This paper proposes to group the ultrasonic transducers by their impedances. Several sub-arrays are thereafter formed and equalized individually. The comparison results demonstrate that the propose sub-array equalization technique can suppress the nonlinear distortion of the PAL more effectively than the previous method.

scholarly journals Trends and Source Contribution Characteristics of SO2, NOX, PM10 and PM2.5 Emissions in Sichuan Province from 2013 to 2017

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 189
Author(s):  
Min He ◽  
Junhui Chen ◽  
Yuming He ◽  
Yuan Li ◽  
Qichao Long ◽  
...  
Keyword(s):  
Air Quality ◽  
Sichuan Province ◽  
Control Measures ◽  
So2 Emission ◽  
Source Contribution ◽  
The Past ◽  
Mobile Sources ◽  
Pm10 And Pm2.5 ◽  
Comparison Results ◽  
Pm2.5 Emissions

As one of the most populated regions in China, Sichuan province had been suffering from deteriorated air quality due to the dramatic growth of economy and vehicles in recent years. To deal with the increasingly serious air quality problem, Sichuan government agencies had made great efforts to formulate various control measures and policies during the past decade. In order to better understand the emission control progress in recent years and to guide further control policy formulation, the emission trends and source contribution characteristics of SO2, NOX, PM10 and PM2.5 from 2013 to 2017 were characterized by using emission factor approach in this study. The results indicated that SO2 emission decreased rapidly during 2013–2017 with total emission decreased by 52%. NOX emission decreased during 2013–2015 but started to increase slightly afterward. PM10 and PM2.5 emissions went down consistently during the study period, decreased by 26% and 25%, respectively. In summary, the contribution of power plants kept decreasing, while contribution of industrial combustion remained steady in the past 5 years. The contribution of industrial processes increased for SO2 emission, and decreased slightly for NOX, PM10 and PM2.5 emissions. The on-road mobile sources were the largest emission contributor for NOX, accounting for about 32–40%, and its contribution increased during 2013–2015 and then decreased. It was worth mentioning that nonroad mobile sources and natural gas fired boilers were becoming important NOX contributors in Sichuan. Fugitive dust were the key emission sources for PM10 and PM2.5, and the contribution kept increasing in the study period. Comparison results with other inventories, satellite data and ground observations indicated that emission trends developed in this research were relatively credible.

scholarly journals A System in Package Based on a Piezoelectric Micromachined Ultrasonic Transducer Matrix for Ranging Applications

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2590
Author(s):  
Alexandre Robichaud ◽  
Dominic Deslandes ◽  
Paul-Vahé Cicek ◽  
Frederic Nabki
Keyword(s):  
High Voltage ◽  
Integrated Circuit ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Transimpedance Amplifier ◽  
Measurement Results ◽  
Ultrasonic Ranging ◽  
High Voltage Pulser ◽  
Working Frequency ◽  
Simulation Results

This paper proposes a system in package (SiP) for ultrasonic ranging composed of a 4 × 8 matrix of piezoelectric micromachined ultrasonic transducers (PMUT) and an interface integrated circuit (IC). The PMUT matrix is fabricated using the PiezoMUMPS process and the IC is implemented in the AMS 0.35 µm technology. Simulation results for the PMUT are compared to the measurement results, and an equivalent circuit has been derived to allow a better approximation of the load of the PMUT on the IC. The control circuit is composed of a high-voltage pulser to drive the PMUT for transmission and of a transimpedance amplifier to amplify the received echo. The working frequency of the system is 1.5 MHz.

Manage the Risk of Turbine Rotor Failure

2010 ◽  
Author(s):  
David Yates ◽  
Angelo Tarantino ◽  
Joop Kraijesteijn
Keyword(s):  
Ultrasonic Transducer ◽  
Large Body ◽  
The United States ◽  
Turbine Rotor ◽  
Operational Reliability ◽  
Ultrasonic Transducers ◽  
Economic Costs ◽  
Utility Industry ◽  
Power Generation Equipment ◽  
Accepted Practice

Turbine rotors failure has resulted in a broad spectrum of events ranging from catastrophic burst to prolonged forced outages that ultimately have significant economic costs for affected utilities. Avoiding turbine rotor failure and its associated cost requires a detailed understanding of the operational reliability of power generation equipment. Nearly all large body turbine and generator rotors manufactured in the United States typically have a central bore hole that provides suitable access from which to conduct various material inspections. The term “boresonics” has become synonymous with the procedure for performing ultrasonic examination of turbine rotor material as conducted from the surface of a central bore cavity. Boresonics is now a fairly common and accepted practice throughout the utility industry. In general, boresonics involves passing ultrasonic transducers through the rotor bore to search a given volume of material for flaws at different locations and orientations within a rotor forging. Each individual ultrasonic transducer has specific inherent performance characteristics based on known wave physics that governs the art of ultrasonic testing. The results of boresonic inspections offer utility engineers a basis for making intelligent decisions on the condition of turbine and generator rotors. This paper describes how boresonic inspections are typically performed in the industry. Furthermore, the paper will give a description of the equipment and required skills of the system operators and will present examples of findings based on KEMA’s experience in this field.

Method for Modeling Ultrasonic Driving Circuit and Designing Matching Network

2012 ◽  
Vol 629 ◽  
pp. 682-687 ◽  
Author(s):  
Bo Xiong Wang ◽  
Wen Feng Liu ◽  
Jian Nan Liu ◽  
Yuan Yuan Cui ◽  
Xiu Zhia Luo
Keyword(s):  
Time Domain ◽  
Power Supply ◽  
Ultrasonic Testing ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Matching Network ◽  
Matching Networks ◽  
Impedance Characteristics ◽  
Driving Circuit ◽  
Attenuation Characteristics

The performances of ultrasonic testing systems are greatly affected by the impedance characteristics of ultrasonic transducers. Conventional methods for designing matching networks consider only the characteristics of matching elements and transducer, while ignoring the effects of other elements of emission circuit. As a consequence, such method cannot give out satisfactory results. In this paper, a modeling method for ultrasonic driving circuits is proposed, which takes into account the power supply, the transformer, the matching networks, as well as the ultrasonic transducer. This method focuses on the performances both in time domain and in frequency domain. A computer simulation and experiments show that this method can provide better attenuation characteristics and energy transmission, and can be widely used for analyzing and designing matching network for ultrasonic testing systems.

scholarly journals Use of Thermodynamic Orientors to Assess the Efficiency of Ecosystems: A Case Study in the Lagoon of Venice

2002 ◽  
Vol 2 ◽  
pp. 255-260 ◽  
Author(s):  
Simone Bastianoni
Keyword(s):  
Aquatic Ecosystems ◽  
Fish Farming ◽  
Venice Lagoon ◽  
Ecological Systems ◽  
Actual State ◽  
Lagoon Of Venice ◽  
The Past ◽  
Comparison Results ◽  
The One

So-called orientors have been introduced at the interface between ecology and thermodynamics. Two have been chosen here to compare the characteristics of five ecological systems: exergy, which is related to the degree of organization of a system and represents the biogeochemical energy of a system, and emergy, which is defined as the total amount of solar energy directly or indirectly required to generate a product or a service. They represent two complementary aspects of a system: the actual state and the past work needed to reach that state. The ratio of exergy to the emergy flow indicates the efficiency of an ecosystem in producing or maintaining its organization.The main system under study is a portion of the Venice Lagoon, which is used as a fish farming basin. Four other aquatic ecosystems were considered for comparison. Results show that the ecosystem within the Venice Lagoon is the one with the highest efficiency in transforming the available inputs in organization of the system. This fact is due to human intervention, which is very limited but also very effective.

scholarly journals Designing the ultrasonic system used in industrial air filtration based on the ultrasonic cavitation phenomenon

2019 ◽  
Vol 290 ◽  
pp. 11009
Author(s):  
Dan Niţoi ◽  
Zoia Apostolescu ◽  
Constantin Petriceanu ◽  
Corneliu Rontescu
Keyword(s):  
Ultrasonic Transducer ◽  
Ultrasonic Cavitation ◽  
Ultrasonic Transducers ◽  
Air Purification ◽  
Acoustic System ◽  
Purification Process ◽  
Air Filtration ◽  
Air Filter ◽  
Cavitation Phenomenon ◽  
Working Method

The paper presents the activity developed developed in the field of polluted air purification from industrial shop (paint shops, foundries, welding constructions, forging, etc.). The advantages of using ultrasounds in the pollutant air filtration and purification process and an ultrasonic filter designed are presented considering the ultrasonic cavitation phenomenon. The main computational and construction elements of the ultra-acoustic system used in the design of the air filter are presented in the paper. The work focuses in the design of the main part of the ultrasonic system represented by ultrasonic transducer. In this case, the transducer network that is used in ultrasonic cavitation method consists of ten ultrasonic transducers. Each one of them consists of asymmetrical passive elements (reflector and radiant element).The design steps and the use of FEM as working method will provide the theoretical basis of the operation of the ultrasonic system so that it allows air filtration based on the ultrasonic acoustic cavitation phenomenon.

scholarly journals AlN-on-Si Square Diaphragm Piezoelectric Micromachined Ultrasonic Transducer with Extended Range of Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 913 ◽  
Author(s):  
Suresh Alasatri ◽  
Libor Rufer ◽  
Joshua En-Yuan Lee
Keyword(s):  
Printed Circuit Board ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Circuit Board ◽  
Detection Range ◽  
Range Finding ◽  
Sensing Applications ◽  
Current State ◽  
Wire Bonds ◽  
Extended Range

We present aluminum nitride (AlN) on silicon (Si) CMOS-compatible piezoelectric micromachined ultrasonic transducers (pMUTs) with an extended detection range of up to 140 cm for touchless sensing applications. The reported performance surpasses the current state-of-art for AlN-based pMUTs in terms of the maximum range of detection using just a pair of pMUTs (as opposed to an array of pMUTs). The extended range of detection has been realized by using a larger diaphragm allowed by fabricating a thicker diaphragm than most other pMUTs reported to date. Using a pair of pMUTs, we experimentally demonstrate the capability of range-finding by correlating the time-of-flight (TOF) between the transmit (TX) and receive (RX) pulse. The results were obtained using an experimental setup where the MEMS chip was interconnected with a customized printed circuit board (PCB) using Al wire bonds.

scholarly journals Advances in Capacitive Micromachined Ultrasonic Transducers

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 152 ◽  
Author(s):  
Kevin Brenner ◽  
Arif Ergun ◽  
Kamyar Firouzi ◽  
Morten Rasmussen ◽  
Quintin Stedman ◽  
...  
Keyword(s):  
Review Paper ◽  
Rapid Development ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Imaging Systems ◽  
Future Trends ◽  
Levels Of Abstraction ◽  
Commercial Success ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Capacitive Micromachined Ultrasonic Transducer

Capacitive micromachined ultrasonic transducer (CMUT) technology has enjoyed rapid development in the last decade. Advancements both in fabrication and integration, coupled with improved modelling, has enabled CMUTs to make their way into mainstream ultrasound imaging systems and find commercial success. In this review paper, we touch upon recent advancements in CMUT technology at all levels of abstraction; modeling, fabrication, integration, and applications. Regarding applications, we discuss future trends for CMUTs and their impact within the broad field of biomedical imaging.

Sign in / Sign up

Export Citation Format

Share Document