K12703 ; 14/43
- 14 -
Program page F
Program pages from B to E
Program page A
[Electronic shutter operation mode]
Shutter system = Continuous/asynchronous
Type of shutter speed = High speed/ low speed
Electronic shutter table = Correspondence relation
b/w shutter switch position and shutter speed
[Other operation modes]
Scanning system = Normal /Partial
[Level setting]
Gain setting value = (Saved as the internal value)
Offset = (Saved as the internal value)
And others
(5-4) Gain setting of preamplifier
● Gain variable amplifier and integrated gain
The image signal output from CCD is amplified inside the
camera through the fixed gain amplifier on the anterior
stage and then through the following variable gain amplifier
before being input into the A/D converter.
The left block chart shows this flow.
(Note) The gain value (dB) described here is the one based on
the CCD output (0 dB) as the baseline.
● Correlation between MGC gain setting value and MGC gain
This equipment is controlled by giving the MGC setting
value. The correlation between this setting value and
the MGC gain (integrated gain including the gain of the
variable gain amplifier and that of the fixed gain
amplifier) is shown in the right graph.
(Note) When the CCD element receives excessive light
with a low gain value of the amplifier due to the
restriction of the dynamic range of the CCD light
receiving element, the signals of the nonlinear
area of the CCD element and the preamplifier
are 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 or downward.
● The brightness of the saturating area does not reach 1023.
(5-5) Program page setting
The FC series cameras are internally equipped with nonvolatile memories
then various operation mode settings and level settings can be stored in
them. The setting items are stored in the virtual pages (hereinafter referred
to as
“program pages”) inside the camera.
This camera has 6 program pages of
“A”, “B”, “C”, “D”, “E” and “F” (right
figure).
The camera starts operating according to the various settings stored in the
relevant page when the mode switch is at any one of the positions from
“A”
to
“F” at the time of power-on.
(!) As this camera is not equipped with the substantial shutter setting switch
on the rear panel,
“Mode switch” described here means setting values of
hypothetical mode switch set on the memory inside the camera.
The position of this (hypothetical) mode switch can be set, read and
saved with serial communication command.
(Note) The memory has the configuration area aside from the saving area
of the program pages that is independent from the program pages.
The common setting items (Configuration items) are saved on this area.
ＣＣＤ
P r e a m p lif ie r
Ａ／ Ｄ
Ｇ ＡＩＮ
Var iable gain amplifier
0dB
（
Fixed
）
I n t e g r a t e d g a in
M G C s e tt in g
Fixed gain amplifier
MG C G A IN CO DE
M
G
C
G
A
IN
(d
B
)
10
20
30
40
20
40
6 0
80
A0
C0
E0 (h ex )
32
64
9 6
12 8
16 0
192
224 (d ec)
Fig. 5-3 Gain setting
Fig. 5-4 Gain characteristics
