The task in AM detection is
illustrated here. The listener gets a warning followed by two interval
indicators. During one interval, randomly chosen, an AM sound is presented;
in the other interval the same sound but unmodulated is presented. The
listener chooses the interval containing the AM sound and receives feedback.
The modulation depth is varied to find the threshold for AM detection, the
amount of modulation required to hear the modulation some proportion of the
time. |