Modeling and effect of distortion product generated by harmonic complex tones

To study deeply the effect of distortion product on auditory perception, a functional model is proposed to generate distortion products at frequencies below those of primary stimuli. The operations include calculating different power of the stimuli, low pass filtering, searching optimum weights, and summing the weighted signals across all filtering channels. The model uses simulate annealing and genetic algorithm to search the globally optimum weights. Moreover, this paper studies the effect of distortion products on pitch perception for unresolved harmonics based on the proposed model. Results find that distortion products could enhance the resolvability and temporal information of the harmonics. Thus, it is suggested to use background noise with appropriate sound levels to mask distortion products to reduce the effect on pitch perception.