The fundamental frequency of EIG events is determined directly, without first
detecting the events themselves. Use is made of an analysis window containing more
than one event (3-5). Techniques (1-8) are utilized which are somewhat similar
to those utilized to detect, and estimate pitch in speech processing. The invention
is based on two important biological discoveries. The first is that the EIG is
generated by a functional pace maker. The second is that the EIG signal is quasi-periodic
most of the time. The use of pitch detection algorithms is based on the essentially
quasi-periodic nature of the EIG signal. Quasi-periodic means that the intervals
between successive events are not exactly identical, but may vary slightly, that
the amplitude and shape of successive events may also exhibit some variance.
