Measuring coherence of a surface scatter channel with a wideband parametric array

1984 ◽  
Vol 76 (S1) ◽  
pp. S78-S78
Author(s):  
Sharad Singhal
Keyword(s):  
Parametric Array ◽  
Surface Scatter

A micromachined efficient parametric array loudspeaker with a wide radiation frequency band

2015 ◽  
Vol 137 (4) ◽  
pp. 1732-1743 ◽  
Author(s):  
Yub Je ◽  
Haksue Lee ◽  
Kyounghun Been ◽  
Wonkyu Moon
Keyword(s):  
Frequency Band ◽  
Radiation Frequency ◽  
Parametric Array

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.

Surface scatter effects in grazing incidence x-ray telescopes

1998 ◽  
Author(s):  
James E. Harvey ◽  
Patrick L. Thompson ◽  
Cynthia L. Vernold
Keyword(s):  
Grazing Incidence ◽  
X Ray ◽  
Surface Scatter

Synthesis of arbitrary broadband signals for a parametric array

1982 ◽  
Vol 72 (1) ◽  
pp. 238-244 ◽  
Author(s):  
Sharad Singhal ◽  
John G. Zornig
Keyword(s):  
Parametric Array

Time domain study of the terminated transient parametric array

1983 ◽  
Vol 73 (6) ◽  
pp. 1972-1978 ◽  
Author(s):  
Nicholas G. Pace ◽  
Robert V. Ceen
Keyword(s):  
Time Domain ◽  
Parametric Array
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