Shiori Yu, Hiryu Shizuko, Watanabe Yu, Riquimaroux Hiroshi, Watanabe Yoshiaki
Faculty of Engineering, Doshisha University, Kyotanabe, Japan.
J Acoust Soc Am. 2009 Sep;126(3):EL80-5. doi: 10.1121/1.3186798.
Because horseshoe bats emit a long-duration pulse, the returning echo temporally overlaps with the emitted pulse during echolocation. Here, the pulse-echo interaction that horseshoe bats actually experience during flight was examined using onboard telemetry sound recordings. Doppler-shifted returning echoes produced beats in the amplitude patterns of constant-frequency components. Bats shortened the pulse duration with target distance, but the overlap duration was at least 8 ms within the approach phase. The computations suggest that the phase difference in slowly amplitude-modulated sound (the beat signal) provides a useful cue for target localization.
因为菊头蝠发出持续时间较长的脉冲，在回声定位过程中，返回的回声在时间上与发出的脉冲重叠。在此，利用机载遥测录音研究了菊头蝠在飞行过程中实际经历的脉冲-回声相互作用。多普勒频移的返回回声在恒频分量的振幅模式中产生拍频。蝙蝠会随着目标距离缩短脉冲持续时间，但在接近阶段重叠持续时间至少为8毫秒。计算结果表明，缓慢调幅声音（拍频信号）中的相位差为目标定位提供了有用的线索。
