Video Inputs - AV...DV
Four analog video input ports are located in both external camera and internal video connectors. The ports are named AV, BV, CV, and DV.
Video Inputs - AV..DV
Each port is physically made up of two pins named, xV+ and xV-; with x = {A, B, C, D}. The video signal is applied across xV+ and xV-; the "warm wire" of the transmission line transporting the video signal "x" has to be connected to the xV+ pin while the "cold wire" of the transmission line has to be connected to the corresponding xV- pin. If the transmission line is a coaxial line, the "warm wire" is the inner conductor and the "cold wire" is the outer conductor.
Both pins shows an input impedance of 22K to the chassis ground and the xV input is further decoupled to the ground by a 100 nF capacitor. The input port is a quasi-differential(*) input since xV+ and xV- exhibit different impedance to the ground.
The video signal flows through a common mode choke that attenuates the common mode noise of the signal. The differential input is terminated by a switchable 75Ω termination resistor. The termination resistor is disconnected during the initialization of the board and can be activated under software control(**). The filtered video signal is applied to the differential input port of the A to D converter through a pair of coupling capacitors.
(*) fully symmetric video signals are not allowed.
(**) MultiCam parameter: VideoTerminator.
DC Characteristics
Video Inputs - DC characteristics |
Min |
Typ. |
Max |
Units |
Input voltage range -Absolute max rating |
-5 |
|
+5 |
V |
Differential input impedance - Terminator OFF |
|
10 |
|
kΩ |
Differential input impedance - Terminator ON |
|
75 |
|
Ω |
Common-mode input impedance to GND |
|
22 |
|
kΩ |