Zur Nichtlinearität des Gehörs

Two kinds of nonlinearity of the ear are studied. One of them refers to the hydrodynamical (Section 1), the other one to the frequency theory (Section 2). Excursions of finite amplitude produce on the partition wall of the cochlea secondary waves of higher harmonics or combination frequencies. Secondary waves of frequencies higher than the primary ones are suppressed, whereas secondary waves of lower frequencies (beat frequencies) generate separate maxima on the partition wall, as postulated by ‘place’ theory.

To understand nonlinearity, the frequency theory may be applied also to small amplitudes. The nerve impulses, which are connected to a certain phase of oscillation of the partition wall, may be integrated into a pulse, which is both amplitude- and phase-modulated. The pulse repetition frequency is equal to one of the primary frequencies, whereas the fundamental frequency of the phase- and amplitude-modulation is equal to the beat frequency of the first or higher order.