摘要:

A novel type of line microphone is described that utilizes a distributed input primarily for the purpose of improving signal‐to‐wind‐noise ratio. The input to the transducer takes place through a tapered pipe that is coupled to the atmosphere by means of acoustical resistances uniformly spaced along the length of the pipe. The relationship between the resistances of the openings and the longitudinal variation in the characteristic impedance of the pipe is so adjusted as to make the system nonreflecting. Microphones of this type have been constructed for use in the frequency range below 1 cps for the purpose of studying atmospheric pressure oscillations in this range. A prototype, 1980 ft long with 100 openings, which gives an improvement in the signal‐to‐noise ratio of as much as 20 db under severe wind conditions, is described.

ISSN:0001-4966    

DOI:10.1121/1.1907747

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

摘要:

Both amplitude and phase spectra are needed to characterize transient functions completely. Analysis shows how these spectra can be obtained from the envelopes of the line spectra of the even and odd parts of a transient function made to recur in time. Instrumentation is described for the convenient determination of these line spectra.

ISSN:0001-4966    

DOI:10.1121/1.1907748

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907749

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP