BOBCAT HD-SDI
Hardware User’s Manual
Imperx, Inc.
Rev. 1.4
6421 Congress Ave.
6/2/2014
Boca Raton, FL 33487
+1 (561) 989-0006
47 of 175
signal output level and gain/offset. Theoretically, the black level should reside
at 0 volts and the gain changes should only lead to increasing the amplitude of
the video signal. Since the camera has two separate video outputs coming out
of the CCD, there is always some offset misbalance between the video outputs.
Thus, changing the AFE gain leads to a change in the offset level and to a
further misbalance between the two video signals. To correct the balance
between two signals for a particular gain, the user should always adjust the
offset for each output – refer to the Camera Configuration section. The overall
camera gain can be calculated using formula 2.3, where Fixed Gain (FG) is
user selectable (- 3dB, 0, 3 dB, or 6dB).
VGA Gain [dB] = FG [dB] + 0.0351 x
gcode
(2.3)
Figure 2.8 – AFE gain and offset.
2.6.2.
Digital Domain – manual control
The camera has a built in digital gain and offset control. There are 20 possible
digital gain levels from 1.0x to 3.0x with step of 0.1x, and 1024 offset levels
from (–511, to + 511).
2.6.3.
Automatic Gain Control (AGC)
The camera can be set to automatic gain (and exposure) control in order to
keep the same image brightness during changing light conditions. In this mode
the user sets the image brightness (luminance) to be maintained, and the
camera adjusts the gain accordingly. The user can select the average or peak
brightness to be maintained. The camera starts with changing the gain within
lig h t in t e n s it y
vi
de
o o
ut
put
b l a c k l e v e l
p i x el o u t p u t
0 V
A F E g a in
A F E o u tp u t
~ 2 0 m V o f fs e t
