iWire Audio Marker for marking the onset of auditory stimulus
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
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.