CHAPTER EIGHT
DPOAE test
70
DPOAE test
8.2.1
Line and Bar graphs
The two screens display the same test data graphically, either as a line
graph or a bar graph.
The blue dots or bars at each frequency show the DPOAE signal level and
the red section represents the noise level in this frequency region.
A tick/checkmark will appear above a bar/dot if the DP at that frequency
has met its pass criteria. Please refer to the
Configuration
chapter for
further information on the DP pass criteria.
If local
Norms
have been set in the test set up area then they will
be displayed as a grey shaded area or brackets (see chapter
15
Configuration
). Norms are for indication only and do not affect stop
criteria.
The F2 frequencies are displayed below the bars/dots. The blue section of
each band represents the DP signal level at the 2F2-F1 frequency and the
red section represents the noise level in this frequency region.
If either the OAE signal or noise level at a DP frequency is greater
than 20dB SPL, an up arrow will appear above the band to show the
level is off the graphical scale.
If no data has been collected at any given frequency then no
histogram will be drawn and a diamond symbol will appear instead. If
at a particular frequency the environmental noise level is high during data
collection, no good data will be collected at that frequency and the diamond
symbol may remain for a number of loops. In constant noise the diamond
may be displayed throughout the complete test.