Moore B C, Poon P W, Bacon S P, Glasberg B R
J Acoust Soc Am. 1987 Jun;81(6):1873-80. doi: 10.1121/1.394751.
Recent experiments have shown that frequency selectivity measured in tone-on-tone simultaneous masking improves with increasing delay of a brief signal relative to the onset of a longer duration gated masker. To determine whether a similar improvement occurs for a notched-noise masker, threshold was measured for a 20-ms signal presented at the beginning, the temporal center, or the end of the 400-ms masker (simultaneous masking), or immediately following the masker (forward masking). The notch width was varied systematically and the notch was placed both symmetrically and asymmetrically about the 1-kHz signal frequency. Growth-of-masking functions were determined for each temporal condition, for a noise masker without a spectral notch. These functions were used to express the thresholds from the notched-noise experiment in terms of the level of a flat-spectrum noise which would produce the same threshold. In simultaneous masking the auditory filter shapes derived from the transformed data did not change significantly with signal delay, suggesting that the selectivity of the auditory filter does not develop over time. In forward masking the auditory filter shapes were sharper than those for simultaneous masking, particularly on the high-frequency side, which was attributed to suppression.
最近的实验表明，在纯音对纯音同时掩蔽中测量的频率选择性，会随着短暂信号相对于较长持续时间门控掩蔽器起始时间的延迟增加而提高。为了确定对于带通噪声掩蔽器是否会出现类似的改善，对在400毫秒掩蔽器的开始、时间中心或结束时呈现的20毫秒信号（同时掩蔽），或在掩蔽器之后立即呈现的信号（前向掩蔽）测量阈值。带通宽度系统地变化，并且带通围绕1千赫兹信号频率对称和不对称地放置。针对每个时间条件，为没有频谱带通的噪声掩蔽器确定掩蔽增长函数。这些函数用于根据会产生相同阈值的平坦频谱噪声的电平来表示带通噪声实验中的阈值。在同时掩蔽中，从变换后的数据得出的听觉滤波器形状不会随着信号延迟而显著变化，这表明听觉滤波器的选择性不会随时间发展。在前向掩蔽中，听觉滤波器形状比同时掩蔽时更尖锐，特别是在高频侧，这归因于抑制作用。
