Study on Detectability of Signals by Utilizing Differences in Their Amplitude Modulation

抄録

Auditory search experiments were conducted to investigate the detectability of target signals with regard to movements in temporal envelopes. The movements in the temporal envelopes of signals were defined as the mean value of slopes, i.e., the first-order approximation of the temporal envelopes. The movements were systematically controlled by band-pass filtering on the modulation spectrum of the signals. The movements of background signals in each target signal were set to be different from the movements between target and background signals. Stimuli were composed of different temporal envelopes with a noise carrier. 1/2-octave band-noise as a carrier was used in which the center frequency of the carrier was 1380 Hz. Participants were required to determine whether they heard the target signal with the background signals. The results obtained from auditory search experiments demonstrated that the detectability of each target signal could be improved when the movements of the target and background signals differed. The results revealed that the difference in the movements of the signals affected the detectability of the signals.