Information Systems and Global Services, Lockheed Martin Corp., 3375 Koapaka Street, Suite I-500, Honolulu, Hawaii 96819, USA.
J Acoust Soc Am. 2012 Aug;132(2):1222-8. doi: 10.1121/1.4731212.
High-frequency auditory filter shapes of an Atlantic bottlenose dolphin (Tursiops truncatus) were measured using a notched noise masking source centered on pure tone signals at frequencies of 40, 60, 80 and 100 kHz. A dolphin was trained to swim into a hoop station facing the noise/signal transducer located at a distance of 2 m. The dolphin's masked threshold was determined using an up-down staircase method as the width of the notched noise was randomly varied from 0, 0.2, 04, 0.6, and 0.8 times the test tone frequency. The masked threshold decreased as the width of the notched increased and less noise fell within the auditory filter associated with the test tone. The auditory filter shapes were approximated by fitting a roex (p,r(r)) function to the masked threshold results. A constant-Q value of 8.4 modeled the results within the frequency range of 40 to 100 kHz relatively well. However, between 60 and 100 kHz, the 3 dB bandwidth was relatively similar between 9.5 and 10 kHz, indicating a constant-bandwidth system in this frequency range The mean equivalent rectangular bandwidth calculated from the filter shape was approximately 16.0%, 17.0%, 13.6% and 11.3% of the tone frequencies of 40, 60, 80, and 100 kHz.
高频听觉滤波器形状的大西洋宽吻海豚（Tursiops truncatus）使用中心位于纯音信号上的缺口噪声掩蔽源进行测量，频率分别为 40、60、80 和 100 kHz。海豚被训练成面对位于 2 米远的噪声/信号换能器的环站游泳。海豚的掩蔽阈值通过升序降序阶梯法确定，缺口噪声的宽度随机变化为测试音调频率的 0、0.2、0.4、0.6 和 0.8 倍。掩蔽阈值随着缺口宽度的增加而减小，较少的噪声落在与测试音调相关的听觉滤波器内。听觉滤波器形状通过将 roex（p，r（r））函数拟合到掩蔽阈值结果来近似。恒定 Q 值为 8.4 在 40 至 100 kHz 的频率范围内相对较好地模拟了结果。然而，在 60 至 100 kHz 之间，3 dB 带宽在 9.5 至 10 kHz 之间相对相似，表明在该频率范围内存在恒定带宽系统。从滤波器形状计算出的等效矩形带宽平均值约为 40、60、80 和 100 kHz 音调频率的 16.0%、17.0%、13.6%和 11.3%。
