Archives of Acoustics, 24, 1, pp. 39-48, 1999

An influence of a modulating signal starting phase on the modulation detection

A. P. Sęk
Institute of Acoustics Adam Mickiewicz University
Poland

E. B. Skrodzka
Institute of Acoustics Adam Mickiewicz University
Poland

This paper is concerned with an influence of a modulator starting phase on psychometric functions of amplitude modulation (AM) and frequency modulation (FM) detection, for low modulation rates, i.e. fmod = 2 and 5 Hz. For a sinusoidal carrier at a frequency of 0.25, 1 and 6 kHz it is shown that there is no effect of a sinusoidal modulator starting phase. Data shown in this paper are consistent with predictions of models based on excitation pattern changes and with a concept according to which AM/FM detection at low modulation rates depends mainly on maximum and minimum values of signal amplitude/frequency. Time intervals between beginning of a signal and the moment when the signal reaches maximum/minimum value of amplitude/frequency and a pattern of physical parameter changes as a function of time seem to be less crucial when the changes are continuos in time.
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