Approach to characterize the sound field of pulse‐excited ultrasonic sensors using a Laser‐Doppler vibrometer

1998 ◽  
Vol 103 (5) ◽  
pp. 2975-2975
Author(s):  
Bernd Henning ◽  
Stefan Prange ◽  
Mark Schuart ◽  
Karsten Dierks
Keyword(s):  
Laser Doppler Vibrometer ◽  
Sound Field ◽  
Laser Doppler ◽  
Ultrasonic Sensors

scholarly journals Using a Retro-Reflective Membrane and Laser Doppler Vibrometer for Real-Time Remote Acoustic Sensing and Control

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3866
Author(s):  
Tong Xiao ◽  
Sipei Zhao ◽  
Xiaojun Qiu ◽  
Benjamin Halkon
Keyword(s):  
Active Noise Control ◽  
Laser Doppler Vibrometer ◽  
Sound Field ◽  
Laser Doppler ◽  
Remote Measurement ◽  
Control Applications ◽  
Acoustic Sensing ◽  
Minimal Invasiveness ◽  
Wide Range ◽  
And Control

Microphones have been extensively studied for many decades and their related theories are well-established. However, the physical presence of the sensor itself limits its practicality in many sound field control applications. Laser Doppler vibrometers (LDVs) are commonly used for the remote measurement of surface vibration that are related to the sound field without the introduction of any such physical intervention. This paper investigates the performance and challenges of using a piece of retro-reflective film directly as an acoustic membrane pick-up with an LDV to sense its vibration to form a remote acoustic sensing apparatus. Due to the special properties of the retro-reflective material, the LDV beam can be projected to the target over a wide range of incident angles. Thus, the location of the LDV relative to the pick-up is not severely restricted. This is favourable in many acoustic sensing and control applications. Theoretical analysis and systematic experiments were conducted on the membrane to characterise its performance. One design has been selected for sensing sound pressure level above 20 dB and within the 200 Hz to 4 kHz frequency range. Two example applications—remote speech signal sensing/recording and an active noise control headrest—are presented to demonstrate the benefits of such a remote acoustic sensing apparatus with the retro-reflective material. Particularly, a significant 22.4 dB noise reduction ranging from 300 Hz to 6 kHz has been achieved using the demonstrated active control system. These results demonstrate the potential for such a solution with several key advantages in many applications over traditional microphones, primarily due to its minimal invasiveness.

Temperature coefficient of Young’s modulus of silver microwhiskers determined by a laser Doppler vibration measurement

2021 ◽  
pp. 2150350
Author(s):  
Yijun Jiang ◽  
Mingyuan Lu ◽  
Shiliang Wang ◽  
Han Huang
Keyword(s):  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Single Crystals ◽  
Young’S Modulus ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Young's Modulus ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
Vibration Measurement

Temperature dependence of Young’s modulus of Ag microwhiskers was determined by a laser Doppler vibrometer. The Ag whiskers with diameters in sub-microns were synthesized by the use of physical vapor deposition (PVD). They have a five-fold twinned structure grown along the [1 1 0] direction. The temperature coefficient of Young’s modulus was measured to be [Formula: see text] ppm/K in the range of 300 K to 650 K. The measured values are very close to the reported values of [Formula: see text] ppm/K for bulk Ag single crystals. This finding can benefit the design of Ag-based micro/nano-electromechanical systems or micro/nano-interconnectors operated at elevated or lowered temperatures.

Identification of pavement material properties using a scanning laser Doppler vibrometer

2016 ◽  
Author(s):  
Navid Hasheminejad ◽  
Cedric Vuye ◽  
Wim Van den Bergh ◽  
Joris Dirckx ◽  
Jari Leysen ◽  
...  
Keyword(s):  
Material Properties ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
Scanning Laser ◽  
Scanning Laser Doppler Vibrometer ◽  
Pavement Material
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