Basilar-membrane nonlinearity estimated by pulsation threshold
Basilar-membrane nonlinearity estimated by pulsation threshold
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DOI：
10.1121/1.428318
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发表时间：
2000-01-01
影响因子：
2.4
通讯作者：
Oxenham, AJ
中科院分区：
文献类型：
--
作者：
Plack, CJ;Oxenham, AJ
脉动阈值技术用于估计基底膜（BM）对特征频率（CF）音调的响应。纯音信号与纯音掩蔽器交替。掩蔽器的频率是信号频率的0.6倍。对于从高于绝对阈值约 20 dB 到 85 dB SPL 的信号电平，改变掩蔽电平以找到被感知为“脉冲”或“连续”（脉动阈值）的信号之间发生转变的电平。假设当掩蔽器激励略大于 BM 上调谐到信号的位置处的信号激励时，就会发生转变。如果进一步假设该位置对低频掩蔽器的响应是线性的，则掩蔽函数的形状提供了对信号的 BM 响应的估计。测试了 0.25、0.5、1、2、4 和 8 kHz 的信号频率。 50 至 80 dB SPL 之间信号电平的掩蔽函数的平均斜率分别为 0.76、0.50、0.34、0.32、0.35 和 0.41。结果表明，BM 上的压缩在 CF 为 0.25 至 1 kHz 之间增加，并且对于 1 kHz 及以上的频率大致恒定。尽管需要主观标准，但脉动阈值测量具有相当低的变异性。然而，估计的压缩比早期使用前向掩蔽的研究要小。这里观察到的较小的压缩量可能是由于异频收听的影响。 (C) 2000 年美国声学学会。 [S0001-4966(00)02201-3]。
The pulsation threshold technique was used to estimate the basilar-membrane (BM) response to a tone at characteristic frequency (CF). A pure-tone signal was alternated with a pure-tone masker. The frequency of the masker was 0.6 times that of the signal. For signal levels from around 20 dB above absolute threshold to 85 dB SPL, the masker level was varied to find the level at which a transition occurred between the signal being perceived as ''pulsed'' or ''continuous'' (the pulsation threshold). The transition is assumed to occur when the masker excitation is somewhat greater than the signal excitation at the place on the BM tuned to the signal. If it is assumed further that the response at this place to the lower-frequency masker is linear, then the shape of the masking function provides an estimate of the BM response to the signal. Signal frequencies of 0.25, 0.5, 1, 2, 4, and 8 kHz were tested. The mean slopes of the masking functions for signal levels between 50 and 80 dB SPL were 0.76, 0.50, 0.34, 0.32, 0.35, and 0.41, respectively. The results suggest that compression on the BM increases between CFs of 0.25 and 1 kHz and is roughly constant for frequencies of 1 kHz and above. Despite requiring a subjective criterion, the pulsation threshold measurements had a reasonably low variability. However, the estimated compression was less than in an earlier study using forward masking. The smaller amount of compression observed here may be due to the effects of off-frequency listening. (C) 2000 Acoustical Society of America. [S0001-4966(00)02201-3].