{"title":"Distortion reduction of length-limited sound beam generated by parametric acoustic array","authors":"Hideyuki Nomura, Toi Nakagawa","doi":"10.1016/j.apacoust.2024.110425","DOIUrl":null,"url":null,"abstract":"<div><div>Length-limited sound beams (LLSBs) generated by amplitude- and phase-controlled parametric acoustic arrays with different carrier frequencies (DCFs) are low-frequency directional sound beams with controlled lengths that transmit acoustic information in a specific direction near the sound source. However, a conventional LLSB produces significant distortion, which is caused by intermodulation of multiple primary and secondary waves. This study aims to reduce the distortion of LLSBs by using a pair of parametric arrays with the same carrier frequency (SCF). To verify the effectiveness of an SCF-type emitter, the beam profiles and distortion of the demodulated sound of SCF-type LLSBs were investigated theoretically and experimentally. The results show that adopting the SCF produced LLSBs without a significant sound pressure reduction near the sound source, similar to DCF-type LLSBs. Furthermore, compared to the distortion of the demodulated parametric signal for the DCF-type LLSB, that for the SCF-type LLSB was reduced by several tens of decibels. These results suggest that SCF-type LLSBs effectively present acoustic information with low distortion to the local area.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"230 ","pages":"Article 110425"},"PeriodicalIF":3.4000,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Acoustics","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0003682X24005760","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ACOUSTICS","Score":null,"Total":0}
引用次数: 0
Abstract
Length-limited sound beams (LLSBs) generated by amplitude- and phase-controlled parametric acoustic arrays with different carrier frequencies (DCFs) are low-frequency directional sound beams with controlled lengths that transmit acoustic information in a specific direction near the sound source. However, a conventional LLSB produces significant distortion, which is caused by intermodulation of multiple primary and secondary waves. This study aims to reduce the distortion of LLSBs by using a pair of parametric arrays with the same carrier frequency (SCF). To verify the effectiveness of an SCF-type emitter, the beam profiles and distortion of the demodulated sound of SCF-type LLSBs were investigated theoretically and experimentally. The results show that adopting the SCF produced LLSBs without a significant sound pressure reduction near the sound source, similar to DCF-type LLSBs. Furthermore, compared to the distortion of the demodulated parametric signal for the DCF-type LLSB, that for the SCF-type LLSB was reduced by several tens of decibels. These results suggest that SCF-type LLSBs effectively present acoustic information with low distortion to the local area.
期刊介绍:
Since its launch in 1968, Applied Acoustics has been publishing high quality research papers providing state-of-the-art coverage of research findings for engineers and scientists involved in applications of acoustics in the widest sense.
Applied Acoustics looks not only at recent developments in the understanding of acoustics but also at ways of exploiting that understanding. The Journal aims to encourage the exchange of practical experience through publication and in so doing creates a fund of technological information that can be used for solving related problems. The presentation of information in graphical or tabular form is especially encouraged. If a report of a mathematical development is a necessary part of a paper it is important to ensure that it is there only as an integral part of a practical solution to a problem and is supported by data. Applied Acoustics encourages the exchange of practical experience in the following ways: • Complete Papers • Short Technical Notes • Review Articles; and thereby provides a wealth of technological information that can be used to solve related problems.
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