
Otocheck ABR
User Manual
131
Mode of operation
22.1.1
Stimuli description
Click stimuli: 80µS duration square pulse of alternating polarity.
Chirp stimuli: 2.5ms duration rapidly swept tone of alternating polarity. The
frequency dispersion of the chirp is defined by the delay at frequency
T(f)= k * f^
−d
with k=0.0920, and d=0.4356.
The wide band chirp waveform was cosine filtered in the time domain to
give the required duration and a frequency range of 1686 to 4614Hz (-3dB
points). The waveform and spectra of the short chirp are illustrated below.
Short Chirp time domain (x-axis in samples at 25.6kHz):
Short Chirp frequency domain: