Specifications

The amount of headroom varies from one manufacturer to another, so you
may discover one brand works better than another under certain circumstances, but
the problem does not necessarily lie with the DVR.
THE REAL PROBLEM.
One of the most over looked problems in CCTV installation is the output level
adjustment of the camera. The standard for camera output is SYNC = 40 I.R.E.
units, WHITE = 100 I.R.E. units, and the COLORBURST = 40 I.R.E. units. However
some camera manufacturers have "fudged" the standards some what. We find that
WHITE levels in auto iris and auto shutter control systems to be padded up to 120
I.R.E. units (1.285714 Volts peak to peak). That is 20% above the standard
maximum level established by the Institute of Radio Engineers.
When a camera's WHITE level is set anywhere above 100 I.R.E. units the
video signal can exceed the maximum headroom allowed by the DVR and the
system will go into digital overload resulting in the failure of the DVR to record a
video signal. When a monitor is attached to the video signal the video can be viewed
because a video monitor is not sensitive to overload. This would lead you to believe
that the DVR is non-functional, when actually the camera level is not set correctly.
SOLUTION.
To avoid DVR problems at installation and subsequent service calls the
camera's in the system must be adjusted to the proper standard levels so that the
video will not overload the DVR. It is recommended that a Camera Master or
waveform monitor be obtained to set the camera's level accurately. If the type of
camera you are using will not allow the WHITE level to be set to 100 I.R.E. and you
have already purchased the camera's, then you can insert a video correction
amplifier like the GB-60 and adjust the gain below unity (a loss of signal) to solve the
problem. The Camera Master CM-2 and the Ground Loop Blocker Amplifier GB-60
can be purchased at FM SYSTEMS, INC.
Proper setting of the video levels will correct the problem and an
understanding of what causes the problem will help you to solve other level related
problems with digital equipment in the future. If you would like more information
regarding this or other CCTV related problems call FM SYSTEMS, INC. CCTV
HELP LINE at: 800-235-6960.
CCTV TRAINING MANUAL PAGE 13 OF 28