In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 85, No. 6 ( 1989-06-01), p. 2642-2650
Abstract:
Bats of the species Eptesicus fuscus have been trained to discriminate a stationary simulated target from a target with a virtual distance that jitters from sound to sound. Similar to Simmons [Science 207, 1336–1338 (1979)], a jitter-detection threshold below 1 μs was found. However, Simmons’ decreased performance at a time delay jitter of 30 μs could not be replicated , a critical feature used to postulate the idea that bats employ a coherent cross-correlation receiver for ranging. Such a receiver uses all phase information in the signal for delay estimation and therefore will be biased by phase manipulations. To test for such a bias, a phase jitter of ±45° and a time jitter in the echo were overlaid. It was not found that there was a combination of both where their effects canceled. Full phase information is thus not used in delay estimation. However, bats were able to detect a pure phase jitter, e.g., polarity inversion of the signal. Bats could a lso detect phase jitter in the presence of randomized time jitter and vice versa. Phase jitter and time jitter, therefore, are separable features for a bat. The underlying physiological mechanism is not clear.
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
1989
detail.hit.zdb_id:
1461063-2
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