Control of doppler shift compensation in the greater horseshoe bat,Rhinolophus ferrumequinum
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FlyingRhinolophus ferrumequinum lower the frequency of the constant frequency part (f A ) of the emitted sounds in order to compensate for Doppler shifts caused by the flight speed. The echo frequency (f E ) is kept constant within a frequency band of about 200 Hz, the center frequency of which is about 150 Hz above the average or resting frequency (f R ) emitted by roosting bats shortly before take off. For the compensation they use a feedback control system in which the emission frequency is changed to hold the echo frequency at a criterion value. This feedback system was demonstrated by experiments with bats flying in an experimental wind tunnel and in a He-O2-micture. In the wind tunnelRhinolophus lowers the emission frequency in order to compensate for Doppler shifts which are caused by the ground speed flown by the bat. In the He-O2-mixtureRhinolophus compensates for Doppler shifts which correspond to the different sound speeds in the gas mixture.
Frequency Band, Feedback Control, Wind Tunnel, Center Frequency, Doppler Shift
Journal of comparative physiology, Vol. 82, no. 1 (1973-03).
Schnitzler, Hans-Ulrich, "Control of doppler shift compensation in the greater horseshoe bat,Rhinolophus ferrumequinum" (1973). KIP Articles. 1215.