TY - JOUR
T1 - Variable-rate frequency sweeps and their application to the measurement of otoacoustic emissions
AU - Christensen, Anders T.
AU - Abdala, Carolina
AU - Shera, Christopher A.
N1 - Funding Information:
We thank the two anonymous reviewers for their helpful comments. This work is supported by the National Institutes of Health Grant Nos. R01 DC003552 (C.A.) and R01 DC003687 (C.A.S.).
Publisher Copyright:
© 2019 Acoustical Society of America.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - Swept tones allow the efficient measurement of otoacoustic emissions (OAEs) with fine frequency resolution. Although previous studies have explored the influence of different sweep parameters on the measured OAE, none have directly considered their effects on the measurement noise floor. The present study demonstrates that parameters such as sweep type (e.g., linear or logarithmic), sweep rate, and analysis bandwidth affect the measurement noise and can be manipulated to control the noise floor in individual subjects. Although responses to discrete-tone stimuli can be averaged until the uncertainty of the measurement meets a specified criterion at each frequency, linear or logarithmic sweeps offer no such flexibility. However, measurements of the power spectral density of the ambient noise can be used to construct variable-rate sweeps that yield a prescribed (e.g., constant) noise floor across frequency; in effect, they implement a form of frequency-dependent averaging. The use of noise-compensating frequency sweeps is illustrated by the measurement of distortion-product OAEs at low frequencies, where the ear-canal noise is known to vary significantly.
AB - Swept tones allow the efficient measurement of otoacoustic emissions (OAEs) with fine frequency resolution. Although previous studies have explored the influence of different sweep parameters on the measured OAE, none have directly considered their effects on the measurement noise floor. The present study demonstrates that parameters such as sweep type (e.g., linear or logarithmic), sweep rate, and analysis bandwidth affect the measurement noise and can be manipulated to control the noise floor in individual subjects. Although responses to discrete-tone stimuli can be averaged until the uncertainty of the measurement meets a specified criterion at each frequency, linear or logarithmic sweeps offer no such flexibility. However, measurements of the power spectral density of the ambient noise can be used to construct variable-rate sweeps that yield a prescribed (e.g., constant) noise floor across frequency; in effect, they implement a form of frequency-dependent averaging. The use of noise-compensating frequency sweeps is illustrated by the measurement of distortion-product OAEs at low frequencies, where the ear-canal noise is known to vary significantly.
UR - http://www.scopus.com/inward/record.url?scp=85075594348&partnerID=8YFLogxK
U2 - 10.1121/1.5134058
DO - 10.1121/1.5134058
M3 - Journal article
C2 - 31795700
AN - SCOPUS:85075594348
SN - 0001-4966
VL - 146
SP - 3457
EP - 3465
JO - Journal of the Acoustical Society of America
JF - Journal of the Acoustical Society of America
IS - 5
ER -