The iWire-AM Audio Marker is designed to monitor Audio inputs. When performing audio stimulus experiments the onset and the peak amplitude of the audio are of interest . To record audio one would have to sample the data at a very high sampling speed, like 20,000 samples per second. Other physiological parameters such as Heart rate , GSR, temperature etc, are sampled at a slow sampling rate, like 100 samples per sec. The iWire-AM audio monitor allows the sampling of the audio signal at a slow sampling rate.
The iWire-AM monitors the audio signal at a high sampling rate internally, but only report the maximum value of the signal at the rate that the rest of the system is sampling. For example, if the physiological data is being sampled at 100 samples per second, then there is one sample every 10msec. The iWire-AM will monitor the Audio signal and report the maximum value every 10msec. This is similar to reporting the envelop of the audio signal.
The iWire-AM can monitor a microphone input as well as the Left and Right Channnel of an Audio source.
The Microphone monitoring can be used to detect when the subject responds to a stimuli.
The Audio monitor can be used to detect the exact onset of the sound stimulus being presented to the subject.
