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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Delay accuracy in bat sonar is related to the reciprocal of normalized echo bandwidth, or Q
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Delay accuracy in bat sonar is related to the reciprocal of normalized echo bandwidth, or Q

机译：蝙蝠声纳的延迟精度与归一化回波带宽或Q的倒数有关

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Big brown bats (Eptesicus fuscus) emit wideband, frequency-modulated biosonar sounds and perceive the distance to objects from the delay of echoes. Bats remember delays and patterns of delay from one broadcast to the next, and they may rely on delays to perceive target scenes. While emitting a series of broadcasts, they can detect very small changes in delay based on their estimates of delay for successive echoes, which are derived from an auditory time/frequency representation of frequency-modulated sounds. To understand how bats perceive objects, we need to know how information distributed across the time/frequency surface is brought together to estimate delay. To assess this transformation, we measured how alteration of the frequency content of echoes affects the sharpness of the bat's delay estimates from the distribution of errors in a psychophysical task for detecting changes in delay. For unrestricted echo frequency content and high echo signal-to-noise ratio, bats can detect extremely small changes in delay of about 10 ns. When echo bandwidth is restricted by filtering out low or high frequencies, the bat's delay acuity declines in relation to the reciprocal of relative echo bandwidth, expressed as Q, which also is the relative width of the target impulse response in cycles rather than time. This normalized-time dimension may be efficient for target classification if it leads to target shape being displayed independent of size. This relation may originate from cochlear transduction by parallel frequency channels with active amplification, which creates the auditory time/frequency representation itself. [References: 38]
机译：大棕蝙蝠（Eptesicus fuscus）发出宽带频率调制的生物声波声音，并从回声的延迟感知到物体的距离。蝙蝠会记住从一个广播到另一个广播的延迟和延迟模式，并且它们可能依赖于延迟来感知目标场景。在发出一系列广播时，他们可以根据对连续回声的延迟估计来检测延迟的很小变化，这些估计是从调频声音的听觉时间/频率表示得出的。要了解蝙蝠如何感知物体，我们需要知道如何将分布在时间/频率表面的信息汇总在一起以估计延迟。为了评估这种转变，我们测量了回声的频率含量的变化如何从心理物理任务中的误差分布中影响蝙蝠的延迟估计的清晰度，以检测延迟的变化。对于不受限制的回声频率含量和高回声信噪比，蝙蝠可以检测到大约10 ns的延迟中的微小变化。当通过滤除低频或高频来限制回声带宽时，蝙蝠的延迟灵敏度相对于相对回声带宽的倒数下降，表示为Q，Q也是目标脉冲响应的相对宽度，而不是时间。如果此归一化的时间维度导致目标形状的显示与大小无关，则可能对目标分类有效。这种关系可能源于具有主动放大作用的平行频率频道的耳蜗转导，这本身就产生了听觉时间/频率表示。 [参考：38]

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