Specifications

Chapter 1 — Features 3
Encoder Output
The multiplexer video encoder produces a single video signal
containing field by field samples from all camera inputs. The
signal is provided in both composite and S-Video formats
(color models only) for connection to a video recorder.
Encoder operation is continuous and independent of display
and decoder functions. All inputs are sampled in camera
number order until motion is detected, when active cameras
are sampled more often.
The encoder uses Vertical Interval Signaling (VIS) techniques
to encode system information onto video output to the VCR.
Time, date, camera title, camera number and alarm status
information are placed on the 16 horizontal lines preceding
the first active video line. This technique improves vertical
synchronization recovery and improves graphics degraded
by poor tape recorder performance.
Decoder Output
The multiplexer decoder processes the video output by the
VCR during playback, recovering the video from each cam-
era originally recorded. The decoder digitizes the playback
video and recovers the VIS information encoded onto each
field. The recovered field is written to the video display
memory if required for display.
The call monitor displays full screen images of cameras asso-
ciated with alarms or images from any selected camera. It is
based on switched analog camera video.
Color demodulation is based on luminance and color differ-
ence processing. Demodulation circuitry operates on a line
by line basis and will correctly demodulate chroma informa-
tion conforming to the NTSC (PAL) video standard.
A graphic generator with two interlaced bit mapped pages
provides the alphanumeric and graphic overlays required for
on-screen menus, camera titles and system messages.