Directional Emission and Time Precision as a Function of Target Angle in the Echolocating Bat Carollia Perspicillata
Carollia perspicillata is a frugivorous bat which emits broadband, frequency-modulated pulses through the nostrils. Interference between the nostrils produces complex emission patterns containing amplitude minima at frequency-dependent angles (Fig. 1 and Hartley and Suthers, in preparation). Such patterns imply large, angle-dependent variations in the frequency structure of emitted pulses. The effect that this has on the potential time (target range) precision with which a point target can be located at angles that are off the main axis of emission can be investigated by calculating the autocorrelation function (ACE) of the emitted pulses at such angles. The potential time precision, which is reciprocally related to the effective bandwidth, can then be derived from the envelope of the ACF (Cahlander 1967, Skolnik 1980). This paper presents an analysis of the angle-dependency of time precision in two individual Carollia.
KeywordsMain Axis Sound Field Effective Bandwidth Emission Pattern Sidelobe Level
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