The EEPROM will then be tested by reading the complete EEPROM to
generate
a checksum which will be compared to a checksum
stored
id'
in
the
EEPROM.
If an error is found the word
"CAL
"
will be
flashed on
the HL display and the initialization
process will
continue.
Dip Switch
#3
will be checked to determine which CAL mode is to
be initialized.
If in the OFF position the transducer SPL
calibration mode is selected,and if in the ON position, the
Custom SPL selection mode will be selected.
4.4 MODE INITIALIZATION
When
the
transducer
SPL Calibration
Mode is
selected the
instrument will be initialized as follows:
Tone Type = Current selection
Frequency
,=
Current selection
Channel = OFF
Calibration HL = 10
dB
below the nonextended HL limit
for.
the current transducer and frequency
Transducer SPL = Calibration HL + Current RTL
+10
dB
Pad = Out
Transducer Routing = Current selection
HL Display =Current custom SPL level stored in EEPROM
Response LED = OFF
Stimulus
On LED = OFF
Low Battery Segment = Current state
"+"
Segment = OFF
4.5 EARPHONE SPL CALIBRATION MODE
This Calibration Mode is used to calibrate the SPL for each
stimulus for each transducer.
This is done by adjusting the
selected transducer output SPL level to the specified value
displayed on the HL display.
This SPL value is the sum of the
calibration HL level and the Reference Threshold Level (RTL) for
the current transducer and frequency.
The RTL may be either the
standard
RTL value or
a custom RTL
value
depending on
the
position of Dip Switch
#3
when the Calibration Mode was entered.
The transducer
SPL calibration data is
stored in
EEPROM by
transducer and stimulus.
4.5
.1
TONE TYPE SWITCH
This switch
operates as in the Normal Mode to select
the
Tone
Type of the stimulus.
4.5.2 ROUTING SWITCH
This
switch
operates as
in the Normal
Mode to
select
the
transducer to be calibrated. All transducers must be
calibrated
and they can be calibrated in any sequence.
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