Anritsu MT9812B, Operation Manual, Page: 65 / 144

4-13
Operation
4
4.3 Optical Sensor Operation
POINT
“E-007” is displayed when the zero setting is executed
with insufficient light insulation.
After displaying the value, the MT9812B returns to the
measurement status. In this case, however, the mea-
surement value (absolute value) may not be correct.
Ensure that the metal light insulation cap located on
the unit front panel is attached to the optical connector
and re-execute the zero setting.
The electrical offset of the light-receive circuit within
the optical sensor depends on the ambient tempera-
ture and time elapse.
When the light levels less than –40 dBm are to be mea-
sured or when a high-precision measurement is to be
performed, it is necessary to execute the zero setting
just prior to the start of the measurement.
The execution time mentioned above (30 s) is the typi-
cal value at room temperature (25
°
C). Execution may
occasionally take 2 minutes, especially for a high ambi-
ent temperature.
When the “0 (zero)” of the seven-segment number
moves to the right and left, the execution of zero set-
ting is in progress. Then, you must wait for a while.
If the “0” display does not move, refer to paragraph
“7.4 Troubleshooting.”
4.3.3 Setting Calibration Wavelength (Optical Frequency)
As the photodetector of the optical sensor of the MT9812B has the wavelength
sensitivity characteristics, the sensitivity compensation is required therefore to
acquire the correct absolute measured value.
Automatic compensation is carried out in the MT9812B when setting the wave-
length (optical frequency) of the light to be measured.
(1) Setting of the optical wavelength to be calibrated
Operations Remarks
Press the Prmtr key. Continue pressing the key until the unit display
turns to “nm”.
Press the or key. Select the input digit.
Press the or key. Set the value.
Press the Enter key. The pressing this key establishes the setting.