Specifications

Proper termination can be checked by measuring the SYNC pulse amplitude
anywhere in the video cable. It should read 40 I.R.E. with the termination ON, and
80 I.R.E. with the termination OFF. If the SYNC level does not change when you
remove the termination, the camera or video source is not standard 75 Ohms and
should be serviced or replaced. Problems with V.I. control systems can result if the
level does not double when you remove the termination.
THE BASIC THREE.
To check performance of any CCTV camera installation make sure the SYNC
level is 40 I.R.E. units +/- 5 I.R.E. WHITE level should be 100 I.R.E. units +/- 5
I.R.E.. Remember if you want to run high white level say 120 I.R.E., be sure that all
camera's in the system have the same level of I.R.E +/- 5 I.R.E. Color burst level
should be 40 I.R.E. units +/- 5 I.R.E. SYNC, WHITE, and COLOR BURST are the
three basic measurements to make to insure proper operation of your CCTV
system.
CCTV VIDEO GROUND LOOP PROBLEMS.
When Video Ground Loop problems or 60 cycle Bars occur, they are easy to
see on a video monitor. They look like a horizontal band or bar across the video
monitor that slowly moves up the video screen. These bars can be barely
noticeable, or can be so bad that the video monitor loses lock and breaks up the
picture. If the video camera is Line-Locked to the 60 cycle main power, the bars may
stand still in the picture, but they still obscure picture definition and create customer
complaints.
The source of the 60 cycle bar originates from the power industries use of
local grounds to balance their power grid. Everywhere 60 cycle power is used, a
local ground is attached to the power grid to return all unbalanced current flow to
ground. As an example, you will notice that every main power breaker box will have
a ground wire or conduit going to a ground rod or similar device connected to an
earth ground. Every correctly installed power outlet will have a connection to this
ground.
Not all grounds are created equal. In fact the earth ground in one building is
most likely to have a different voltage potential relative to any other building, even
grounds inside the same building will have different voltages between them, based
on the uneven current flow of the power load.
CCTV TRAINING MANUAL PAGE 3 OF 28