von Klitzing R, Kohlrausch A
Drittes Physikalisches Institut, Universität Göttingen, Germany.
J Acoust Soc Am. 1994 Apr;95(4):2192-201. doi: 10.1121/1.408679.
Masked thresholds were measured with running- and frozen-noise maskers. The 5-kHz signal was 2 ms in duration. The masker was low-pass noise (20 Hz-10 kHz); its total duration was 300 ms. The overall level of the masker was 30, 50, or 70 dB SPL. The onset of the signal was delayed by 0, 3, 8, 18, 198, or 278 ms relative to the onset of the masker. In all frozen-noise measurements, the signal was added to the same fine structure of the noise. Overshoot in frozen noise was measured for two starting phases of the signal that led to a 10-dB difference for large signal-onset delays. In all three configurations (running noise and frozen noise with two different signal phases) masker level had a similar influence on overshoot. At the intermediate masker level (50 dB SPL), a significant amount of overshoot (up to 15 dB) was observed in all three conditions. At the low and the high masker levels, overshoot was very much reduced, and even became negative in most conditions for the 30-dB-SPL masker. For the 50-dB frozen-noise masker, the total variation of thresholds with signal phase was 8 to 11 dB for long signal-onset delays, but only 3 to 6 dB for short delays. For the low- and high-level maskers, where only a small overshoot was observed, the threshold variation with phase for a signal at masker onset was the same as that for the long-delay condition. An explanation for the variation of signal detectability with masker level is proposed that refers explicitly to the compressive input-output characteristic of the basilar membrane at intermediate levels.
使用连续噪声和固定噪声掩蔽器测量掩蔽阈值。5kHz的信号持续时间为2ms。掩蔽器为低通噪声（20Hz - 10kHz）；其总持续时间为300ms。掩蔽器的总体声压级为30、50或70dB SPL。信号的起始相对于掩蔽器的起始延迟0、3、8、18、198或278ms。在所有固定噪声测量中，信号被添加到噪声的相同精细结构中。针对信号的两个起始相位测量了固定噪声中的过冲，这两个起始相位在大的信号起始延迟时会导致10dB的差异。在所有三种配置（连续噪声以及具有两个不同信号相位的固定噪声）中，掩蔽器电平对过冲有类似的影响。在中等掩蔽器电平（50dB SPL）下，在所有三种条件下都观察到了显著的过冲量（高达15dB）。在低掩蔽器电平和高掩蔽器电平下，过冲大大降低，对于30dB SPL的掩蔽器，在大多数情况下甚至变为负值。对于50dB的固定噪声掩蔽器，对于长信号起始延迟，阈值随信号相位的总变化为8至11dB，但对于短延迟仅为3至6dB。对于低电平和高电平掩蔽器，其中仅观察到小的过冲，掩蔽器起始时信号的阈值随相位的变化与长延迟条件下的相同。提出了一种关于信号可检测性随掩蔽器电平变化的解释，该解释明确提及了中等电平下基底膜的压缩输入 - 输出特性。
