Larson Davis System 824, Справочное руководство

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12-4 824 Reference Manual 11/8/00
Linearity measurements can also be
performed using the linearity dis-
play, (page 11-9). Linearity evaluation can easily be performed by placing the
cursor on the audiometric presentation frequency, then vary-
ing the hearing level output and monitoring the measured
level on the 824.
Similarly, cross talk measurements are performed with the
non-test earphone being measured, then comparing the test
earphone level to that measurement.
Any Level-a Screen
This screen is accessed by pressing the VIEW key, then
selecting the SLM/RTA with the up/down arrows and press
the check key
. Once in the SLM+RTA Live screen, press
the up or down arrow
to display the Any Level-a
screen.
This screen displays the current Fast and Slow time aver-
aged sound pressure level reading without frequency
weighting (dBF for flat). This level will vary with the audi-
ometer output, but also may vary due to signal components
other than the audiometric frequency. Therefore, linearity
measurements made with these levels will not be accurate at
lower amplitudes.
The frequency and period of the signal measured by the
sound level meter are also displayed at the bottom of the
screen. It may be necessary to increase the audiometer HL
output level for a more stable measurement.