AVIIVA® EM2-EM4
32
1013D - AVIIVA EM2/EM4 02/11
e2v semiconductors SAS 2011
5.3.6
Gain and Offset
Ultimate Concept
: A different way to set the Gain in order to improve the Tap balance
The “U” Concept has been developed to get a real improvement in term of tuning for the multi-Tap sensors :
As each sensor tap is driven by a different analog Chain, for an increasing of the global gain of the Camera,
each tap can have a different behavior on its own Gain and offset.
This means that to be perfectly adjusted, a balance of the taps should be performed ideally after each
change of the Gain. The Ultimate Concept offers a solution as following:
The Global analog Gain of the Camera is divided in 2 parts :
A preamp-Gain which is composed of several steps (5 x steps of 6dB, from -24dB to 0dB on the AVIIVA
EM2/EM4)
An amplification Gain with a continuous tuning (from 0dB to +8dB on the AVIIVA EM2/EM4)
At each step of Preamp Gain, a Tap balance has been performed in factory for both Gains and Offsets and
saved in ROM memory. When a new value of Preamp Gain is set, the factory settings of the both Gain and
offset balance is automatically reloaded.
For sure, the user can also perform his own balance (automatically or manually) and can save it in one of the
four dedicated memory banks.
After the Preamp Gain level, the user can add more gain by using the Amplification Gain:
The best tuning is when the Amplification Gain is set at its minimum possible
Each change of Preamp Gain value loads automatically the associated values of the Tap balance (Gain and
offset for each sensor tap).
This action takes more time than simply changing the Amplification Gain
Pre Amp
-
-
6
6
-
-
1
1
2
2
-
-
1
1
8
8
-
-
2
2
4
4
Amp
Gain
(0 to +8 dB)
-
-
2
2
4
4
d
d
B
B
-
-
1
1
6
6
d
d
B
B
-
-
1
1
8
8
d
d
B
B
-
-
1
1
0
0
d
d
B
B
-
-
1
1
2
2
d
d
B
B
-
-
4
4
d
d
B
B
-
-
6
6
d
d
B
B
+
+
2
2
d
d
B
B
0
0
+
+
8
8
d
d
B
B
0
0
d
d
B
B
