In a hearing aid having an oscillation detector and a method for establishing
the presence of oscillations in a hearing aid, sinusoidal input signals of the
microphone can be detected, and so oscillations that are present can also be detected.
To this end, the number of digitized sample values in consecutive periods of the
input signal is determined, and a long-term average value NL and a short-term
average value NK are formed from these numbers. When NL and
NK are essentially identical, the presence of oscillations is detected.
