An electronic apparatus (1) supported against a dog's skin to control
vocalizing by the dog electronically converts the vocalizing into a
sequence of signals representing frequencies of the vocalizing, and
operates a controller to determine if each measured frequency lies within
any of a plurality of predetermined frequency sub-ranges and if so,
increments cumulative totals of the frequencies which lie in the
sub-ranges, respectively, to provide a plurality of cumulative totals
that represent a frequency spectrum of the vocalizing. The controller is
operated to determine whether the barking sounds constitute a valid bark
by comparing the frequency spectrum to a predetermined valid bark
frequency spectrum. Appropriate aversive stimulus signals are produced
between first and second stimulus electrodes if the vocalizing sounds
constitute a valid bark.