4.9.5 ATTENUATOR MAXIMUM OUTPUT LEVEL CALIBRATION (D4)
NOTE:
If Default
Data is loaded,
this procedure must be
performed before calibration of earphones.
TEST DISCR
IPTION
__-
If the Microprocessor of the GSI 17 has been replaced or a major
calibration data loss has occurred the Attenuator Maximum output
level must be calibrated.
When performing this calibration, the
operator will measure the output level on the connector
(important
-unloaded)
of the currently
selected transducer
and
adjust the attenuator position
until correct output voltage is
measured.
The calibration data is then stored and the process is
repeated for
all remaining stimuli.
The stimuli may be
calibrated in any order,
but all must be calibrated.
Originally
all output levels were adjusted to 2.5 vrms
*.15
vrms for each
frequency.
The newer GSI
17's
have specific maximum output
levels for calibration.
Serial numbers and output levels are
outlined below.
NOTE
:
When performing this procedure,
output must be unloaded
(no phone plugged in).
SERIAL NUMBERS LESS THAN 1230 (EXCLUDING 1068, 1175r AND 1212)
All frequencies 2.5 vrms
(+.15
vrms)
SERIAL NUMBERS GREATER THAN 1230 (INCLUDING 1230, 1068, 1175, AND 1212)
_
Frequency (Hz)
Voltage (rms)
(2.5
dB)
125
2.30
250
2.30
500
2.15
750
1.90
1
K
2.50
2
K
2.50
3
K
2.50
4
K
2.50
6 K
2.50
8
K
2.50
38
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