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●
Recommended external sync signal
(5-2) Level setting
The level setting is mostly divided into the following two groups:
●
Gain setting
This is to set the gain (amplification ratio) of the
preamplifier between the CCD imaging device
and the A/D converter.
Communication command H’30
●
Offset setting
This is set by the communication command in
serial communication.
Communication command H’32
●
Correlation between gain setting value and observed gain value
The setting value of this equipment is controlled by giving 0 to 255. The setting value and the actual GAIN value are
approximately proportional. The approximate value is calculated by the following equation.
(Note) When the CCD element receives excessive light with the amplifier set at low gain value due to the restriction of the dynamic
range of the CCD light receiving element, the signals of the nonlinear range of the CCD element and the preamplifier may be
output at the high brightness area. In this state, unnatural image (Note below) may appear in the neighborhood of the
saturating signal area of the image due to the characteristic of the nonlinear area. This phenomenon, which is associated with
the saturation characteristic of the CCD element, is not a failure arising from the camera.
To eliminate this phenomenon, reduce the amount of light by stopping down the lens and newly set a higher gain value. Then,
the output signal from the CCD element at the saturating area will be appropriately saturated into a white level for the output.
(Note)The above described unnatural image represents the following states:
●
Black and white look inverted at the saturating area.
●
The outline of the saturating area is blurred.
●
The saturating area slightly shifts upward and downward.
●
The brightness value of the saturating area does not reach 1023.
(Note) The sensitivity correction is sometimes conducted at the factory before shipment using Digital gain function for the purpose of
maintaining sensitivity of the camera. As the output of AD converter are digitally multiplied, the data of some gray levels may be
absent depending output level of AD converter and setting value of digital gain Set the setting value of Digital gain (Control
register: H’31) at “0” to turn the sensitivity correction OFF. The analog gain is employable as per normal.
・
Signal polarity
：
Negative logic
Pulse width
ＨＤ：３．２±１μｓ（Low
level）
ＶＤ：１ ～ １３Ｈ
（Low
level
）
HD Permissible frequency deviation
３０
fps :
１５.７３４ＫＨｚ±１％
６０
fps :
３１.４６８ＫＨｚ±１％
９０
fps :
４７．６７４ＫＨｚ±１％
３０
fps
：８μｓ
８μｓ
ＨＤ
ＶＤ
・
External HD/VD Input phase Phase difference
：３０
fps
±
８
µ
ｓ
：６０
fps
±
４
µ
ｓ
：９０
fps
±
2.6
µ
ｓ
９０
fps
：２
.
６μｓ
６０
fps
：４
μ ｓ
２
.
６μｓ
４μｓ
Signal level
Time
Time
Signal level
Signal level
Time
１０ ２ ３
０
０
１ ０ ２ ３
０
I
ncrease in OFFSET
Increase in GAIN
Image signal
１ ０ ２ ３
（
Before setting adjustment
）
CDS GAIN (dB) = 3.64 + 0.132
×
( Setting value + GOFS [ 7..0 ] ) dB
Communication command 30H Fixed value GAIN OFFSET
Communication command 32H
