Evaluation of an auditory model for echo delay accuracy in wideband biosonar.
Evaluation of an auditory model for echo delay accuracy in wideband biosonar.
复制标题
评估宽带生物声纳中回声延迟精度的听觉模型。
DOI：
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发表时间：
2003
影响因子：
2.4
通讯作者：
J. Simmons
中科院分区：
文献类型：
--
作者：
M. Sanderson;N. Neretti;N. Intrator;J. Simmons
在回声延迟抖动的心理物理任务中，大棕蝠可以在回声信噪比约为 49 dB 时检测到小至 10-20 ns 的变化，在回声信噪比约为 36 dB 时检测到 40 ns 的变化。这种性能可以通过宽带回波的理想相干处理来实现，但人们普遍认为蝙蝠的外围听觉系统无法编码信号波形以在超声波频率下以必要的精度或相位表示延迟。通过使用一组并行带通滤波器对内耳传导进行建模，然后进行低通平滑，检验了这一假设。测试了滤波器组模型的多个版本，以了解平滑滤波器（控制表示一致性的最关键参数）如何影响蝙蝠性能的复制。当以 36 dB 的信噪比进行测试时，该模型使用截止频率为 8 kHz 的二阶平滑滤波器实现了 83 ns 的延迟敏锐度。当信噪比为 50 dB 时，同一模型的延迟敏锐度为 17 ns。对于五阶平滑或较低截止频率，抖动检测阈值比蝙蝠差一个数量级。最令人惊讶的是，滤波器截止频率远低于蝙蝠声纳声音中包含的任何超声波频率，有效的相干接收是可能的。结果表明，只有蝙蝠内耳平滑的频率响应适度提高，才能为后续处理提供完全的相位敏感性，并解释蝙蝠的精细敏锐度或延迟。
In a psychophysical task with echoes that jitter in delay, big brown bats can detect changes as small as 10-20 ns at an echo signal-to-noise ratio of approximately 49 dB and 40 ns at approximately 36 dB. This performance is possible to achieve with ideal coherent processing of the wideband echoes, but it is widely assumed that the bat's peripheral auditory system is incapable of encoding signal waveforms to represent delay with the requisite precision or phase at ultrasonic frequencies. This assumption was examined by modeling inner-ear transduction with a bank of parallel bandpass filters followed by low-pass smoothing. Several versions of the filterbank model were tested to learn how the smoothing filters, which are the most critical parameter for controlling the coherence of the representation, affect replication of the bat's performance. When tested at a signal-to-noise ratio of 36 dB, the model achieved a delay acuity of 83 ns using a second-order smoothing filter with a cutoff frequency of 8 kHz. The same model achieved a delay acuity of 17 ns when tested with a signal-to-noise ratio of 50 dB. Jitter detection thresholds were an order of magnitude worse than the bat for fifth-order smoothing or for lower cutoff frequencies. Most surprising is that effectively coherent reception is possible with filter cutoff frequencies well below any of the ultrasonic frequencies contained in the bat's sonar sounds. The results suggest that only a modest rise in the frequency response of smoothing in the bat's inner ear can confer full phase sensitivity on subsequent processing and account for the bat's fine acuity or delay.
影响因子：
2.4
作者：
SAILLANT, PA;SIMMONS, JA;DEAR, SP
通讯作者：
DEAR, SP