TY - JOUR
T1 - Time-domain demonstration of distributed distortion-product otoacoustic emission components
AU - Martin, Glen K.
AU - Stagner, Barden B.
AU - Lonsbury-Martin, Brenda L.
N1 - Funding Information:
This work was supported by the VA Loma Linda Healthcare System and by grants from NIH (Grant No. DC000613) and the Veterans Administration (VA/RR&D Grant Nos. C7107R and C6212L). The authors thank Alisa Hetrick for technical assistance.
PY - 2013/7
Y1 - 2013/7
N2 - Distortion-product otoacoustic emissions (DPOAEs) were measured in rabbits as time waveforms by employing a phase-rotation technique to cancel all components in the final average, except the 2f1-f2 DPOAE. Subsequent filtering allowed the DPOAE waveform to be clearly visualized in the time domain. In most conditions, f2 was turned off for 6 ms, which produced a gap so that the DPOAE was no longer generated. These procedures allowed the DPOAE onset as well as the decay during the gap to be observed in the time domain. DPOAEs were collected with L1 = L2 = 65-dB sound pressure level primary-tone levels for f2/f1 ratios from 1.25 to 1.01 in 0.02 steps. Findings included the appearance of complex onsets and decays for the DPOAE time waveforms as the f 2/f1 ratio was decreased and the DPOAE level was reduced. These complexities were unaffected by interference tones (ITs) near the DPOAE frequency place (fdp), but could be removed by ITs presented above f2, which also increased DPOAE levels. Similar outcomes were observed when DPOAEs were measured at a sharp notch in the DPOAE level as a function of the f2 primary tone frequency, i.e., DP-gram. Both findings were consistent with the hypothesis that the DPOAE-ratio function, and some notches in the DP-gram, are caused by interactions of distributed DPOAE components with unique phases.
AB - Distortion-product otoacoustic emissions (DPOAEs) were measured in rabbits as time waveforms by employing a phase-rotation technique to cancel all components in the final average, except the 2f1-f2 DPOAE. Subsequent filtering allowed the DPOAE waveform to be clearly visualized in the time domain. In most conditions, f2 was turned off for 6 ms, which produced a gap so that the DPOAE was no longer generated. These procedures allowed the DPOAE onset as well as the decay during the gap to be observed in the time domain. DPOAEs were collected with L1 = L2 = 65-dB sound pressure level primary-tone levels for f2/f1 ratios from 1.25 to 1.01 in 0.02 steps. Findings included the appearance of complex onsets and decays for the DPOAE time waveforms as the f 2/f1 ratio was decreased and the DPOAE level was reduced. These complexities were unaffected by interference tones (ITs) near the DPOAE frequency place (fdp), but could be removed by ITs presented above f2, which also increased DPOAE levels. Similar outcomes were observed when DPOAEs were measured at a sharp notch in the DPOAE level as a function of the f2 primary tone frequency, i.e., DP-gram. Both findings were consistent with the hypothesis that the DPOAE-ratio function, and some notches in the DP-gram, are caused by interactions of distributed DPOAE components with unique phases.
UR - http://www.scopus.com/inward/record.url?scp=84880456375&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84880456375&partnerID=8YFLogxK
U2 - 10.1121/1.4809676
DO - 10.1121/1.4809676
M3 - Article
C2 - 23862812
SN - 0001-4966
VL - 134
SP - 342
EP - 355
JO - Journal of the Acoustical Society of America
JF - Journal of the Acoustical Society of America
IS - 1
ER -