title: Time-selective windowing technique in free-field microphone reciprocity calibration.
abstract: Time-selective windowing techniques, which effectively remove multi-path noise, have been widely utilized for reciprocity calibration of microphone there are still limitations imposed by overlapping signals, particularly at low frequencies and for high Q microphones. Based on a fast Fourier transform analysis, the leakage due to a limited frequency range makes the overlap problem worse, not be perfectly separated. Instead of using conventional low-pass filters that are designed to have a flat response in the frequency range of interest, in this study, a filter with a Dolph-Chebyshev window shape was proposed because it has low sidelobe levels. After removing multi-path noise with a time-selective window, an inverse filter should be applied to compensate for distortion created by the applied filter. The method suggested in this paper extends the possible frequency range of free-field reciprocity calibration to frequencies below 2 kHz.
authors.affiliation: Center for Fluid Flow and Acoustics, Division of Physical Metrology, Korea Research Institute of Standards and Science 267, Gajeong-ro, Yuseong-gu, Daejeon 305-340, Korea. hyusang@kriss.re.kr
authors.forename: Hyu-Sang
authors.initials: HS
authors.lastname: Kwon
authors.forename: Wan-Ho
authors.initials: WH
authors.lastname: Cho
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Suh