Glossary beginning with I

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I

I.C.B.A.

International Committee for Bioloogical Acoustics.

IBAC

International Bioacoustics Council

International Bioacoustics Congress

impuls

See pulse.

impulse

"a brief change of current produced in a circuit. By extension, it could be used for a train of waves (electrical or acoustic) of which it constituted the envelope; but this train would have to be short relative to the interval between it and the next." [1]

References

Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Acoustic Behavior of Animals. Elsevier; 1963.

impulsion

"strictly = impulse... in my experience, not used in the sense in which pulse is used in English, until recently, and then only in partial equivalence, as translated below from Grand LArousse, 1962:

radiotech: train of very high frequency waves, used notably in radar, whcih succeed one another periodically in time intervals of some decades of microseconds, and whose duration varies from some hundreds of microseconds to a fraction of a microsecond.

television: sudden variation of amplitudeof the modulation, used for transmitting time-base sync. signals.

The seocnd of these definitions is much the same as the British Standard for impulse; the first equates to certain limited kinds of pulse, (as well as to impulses), namely (1) of high-frequency waves; and at the same time (2) of short pulse duration (e.g. less than a millisecond).

It does not, however, specify that the pulse duration shall be short relative to interval or period, and this is where the new definition appears to me to depart from time-honoured practice in the French-language, which, when I was working in France 10 years ago, appeared to have no equvalent whatever to the everyday concept of pulse in the English-speaking world; at that time, impulsion, at least among the physicists I worked with, equaed rigorously to impulse, not pulse.

Thus the present situation is taht in the electrical context, impulsion can be used for anything from impulses, s.s. to pulse, provided the latter be of inframillisecond duration and of h.f. current. Pulse in acoustics still has no equivalent." [1]

References

Broughton WB. Glossarial Index. In: Acoustic Behavior of Animals. Acoustic Behavior of Animals. Elsevier; 1963.

interval of recurrence

"lapse of time between the end of one member of a series of more or less irregularly periodic sounds and thebeginning of the next. For the concept to have any real meaning in respect of irregular sounds, it must obviously be a mean of a fair sample." [1]