STSF, a unique technique for near-field acoustic holography and exterior noise measurements

Gade, Svend

doi:10.1016/0389-4304(95)95167-s

Cited by 4 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The linear array contained 17 BSWA microphones of type MPA-201 with a spacing of 0.04 m. The linear array moves parallel to the source plane along the y−axis with 0.04 m intervals to construct 17 × 17 measurement points, as shown in figure 7(d). Two reference microphones were fixed at any location that had no effect on the result to correct the phase of the measured data at different times to obtain the final measured signal matrix [45]. The sampling frequency was 44 100 Hz, and the signal with a second length was analyzed to ensure the stability of the calculation.…”

Section: Performance Comparison Of Different Methods In An Indoor Env...mentioning

confidence: 99%

Sub-wavelength focusing for low-frequency sound sources using an iterative time reversal method

Li¹,

Li²,

Pan³

et al. 2022

Meas. Sci. Technol.

View full text Add to dashboard Cite

Microphone array measurement processed with the image algorithm is commonly performed to identify and quantify noise sources of machines, which is the premise of noise control. However, due to the limitation of the half-wavelength theory, Beamforming and Time Reversal (TR) methods are difficult to separate multiple low-frequency sources. Although near-field acoustic holography can overcome the diffraction limit, it will encounter the ill-posed problem. To avoid solving the inverse problem, iterative time reversal processing (Iterative-TR) is proposed to obtain the sub-wavelength focusing and improve the spatial resolution at low-frequency. The focusing result is corrected step by step with iteration implemented until the result reaches the convergence threshold. The propagation matrix between microphones and focusing points is reconstructed by singular-value normalization to ensure the convergence of the iteration. Numerical simulation results show that Iterative-TR method is able to break through diffraction limit below 1000 Hz within a measurement distance of 0.5 m and reach convergence within 105 iterations that is less than 10 s. The experimental results in indoors with significant reverberation show that Iterative-TR has the ability to stably give the multiple source positions with 0.11 m spacing even at 100 Hz, that is, the spatial resolution reaches 1/31 wavelength. Detailed analysis shows that the overall performance of Iterative-TR outperforms other methods capable of subwavelength focusing for signals below 1000 Hz. The identification of two loudspeakers in the car shows the practicality of the proposed method.

show abstract

Section: Performance Comparison Of Different Methods In An Indoor Env...mentioning

confidence: 99%

Sub-wavelength focusing for low-frequency sound sources using an iterative time reversal method

Li¹,

Li²,

Pan³

et al. 2022

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The basic principle of STSF is to measure cross spectra ol sound pressure over a plane close to the measuring object [1]. in this case a pressure microphone array.…”

Section: Stsf Measurementsmentioning

confidence: 99%

Passby Measurments vs. STSF Passby Simulations

GADE,

RASMUSSEN,

TAYLOR

2024

Noise Control - The Next 25 Years

View full text Add to dashboard Cite

“…To reduce manufacturing and computing cost, we made an instrumentation that moved the probe sequentially over the plane. The sources studied therefore had to be stationary and the phase reference problem arose The use of STSF (Spatial Transform of Sound Field) method enabled this dif culty to be overcome for the case of partially coherent elds [2].…”

Section: Principle Of Acoustic Holographymentioning

confidence: 99%

Air Conditioning Noise Sources Identification Using Acoustic Holography

MOYNET,

GUILHOT,

AZAÏS

2024

Noise Control - The Next 25 Years

View full text Add to dashboard Cite

STSF, a unique technique for near-field acoustic holography and exterior noise measurements

Cited by 4 publications

References 0 publications

Sub-wavelength focusing for low-frequency sound sources using an iterative time reversal method

Sub-wavelength focusing for low-frequency sound sources using an iterative time reversal method

Passby Measurments vs. STSF Passby Simulations

Air Conditioning Noise Sources Identification Using Acoustic Holography

Contact Info

Product

Resources

About