Lecture 3 - The bionic bat

From the 1985 lecture programme:

A special branch of communication involves the use of echoes to replace sight when visibility is poor. In echo systems, the transmitter and receiver are side-by-side and signals are reflected back by surrounding objects. The emitted signal is already known but any changes in the returning echoes can be interpreted to determine the position and nature of the reflecting targets. Two well known examples are radar, using radio waves, and bats which emit high frequency sounds for similar purposes. There are remarkable resemblances between them, even in the variety of ways in which each can work.

We will investigate experimentally the basic principles of a sonar system using sound echoes in air. Progressive improvements to the design will result in high performance instruments that are nicknamed bionic bats. They will be compared both with examples of the real animals and with different kinds of radar and radio telescopes. This highly developed ability of bats accounts in large part for the unusual appearance of many species, often thought to be ugly until their adaptations are understood.

Man-made radar and sonar are now used for many different purposes, from astronomy and geography to commercial fisheries, ornithology and clinical medicine. Some outstanding examples will be demonstrated from a variety of such applications.






David Pye



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