Proposed explanation how a human ear works are very complicated and not explaining possibilities of human ear[1][2]. Proposed method uses the idea of a diffraction grating. Fig. 1 presents the idea. Sampling frequency – 50000 Hz.
On the first level a cochlea is considered as:
- Delay-line (linear for simplicity) implemented as a vector
- Signal detectors along the delay-line – values in the DL
- Sophisticated low-pass filter along the delay-line (not shown on Fig. 1)
Frequency detection takes place on the second and third level. It looks strange, but frequencies to detect should be arbitrary chosen. This values decide which delayed values are added (“legs” of each adder in Fig.1). It was arbitrarily chosen, that 15 values will be taken into consideration for each adder. Notice, that highest frequencies are detected at the beginning of the delay-line, the lowest are more scattered along DL – to the end for lowest detected frequency (fn and f1 in Fig.1 ). So after 15 periods of the frequency fn this frequency in the signal in the rest of the delay-line is useless – look at the explanation of residual hearing effect.
In the used testing program the file coef.sp2 is created. In it, it is possible to see the distribution of addresses along the DL, where the signals for adders are taken. This values are written as characters so it may be useful to look for similarities with connections of ortoneurons and spironeurons (or auditory nerve?) with hair cells in human ear. The Fig. 2 presents the answer of the program for single frequency. It can detect frequencies little higher than highest expected (ultra sounds by bones).
Pictures which show detected frequencies are presented by the program as the PostScript file, and so inserted to the paper (look description of the program). Frequency discriminator in presentation simply changes the order of presented frequencies. To determine, which frequency was on input simply chose the local maximum, or construct the neuronal net, as it is sometimes suggested [4].
/DL in the program is a vector, so is frequency discriminator – which reverts the order of frequencies (f1 - fn)/