Dedicated Micros Sprite Lite Guide D’installation página 4

Installing
Before you start:
Check the contents of the box
The following items are included in the box:
Sprite Lite
PSU
Mains cable with 3-pin plug fitted (North America)
Mains cable without plug fitted (Other regions)
Rack mount kit (rack mount ears and fixing screws)
Setup Guide
Choosing a location for installation
Sprite Lite is designed to be rack or desk mounted. The following precautions must be
taken when installing Sprite Lite:
• Openings in the unit's case are provided for ventilation. To prevent overheating, these
openings should not be blocked or covered.
• Ensure there is a 1" (3cm) gap on either side of the unit.
• Ensure the unit is not located in an area where it is likely to be subjected to mechanical
shocks.
• The unit should be located in an area with low humidity and a minimum of dust. Avoid
places like damp basements or dusty hallways.
2
A quick overview of multiplex recording
A video multiplexer is simply a device that records a multiple number of cameras to a single
videotape. Video multiplexers achieve this by rapidly switching through a number of cameras and
recording this stream of full screen images onto a single videotape.
Normal VHS tapes are used to provide 24, 48, or 72 hours of recordings using a process
known as time-lapse recording. Time-lapse recording extends recording time by slowing
the tape down and recording fewer pictures per second.
To extend recording time per tape, fewer pictures per second are recorded by introducing a
field delay; each time-lapse mode has a field delay. The field delay is the number of fields
or pictures the VCR waits before recording the next picture. For example, a field delay of 8
will record every 8th image to tape.
The amount of time it takes for a camera to be refreshed is called the update rate. The
update rate is affected by the field delay – the greater the field delay, the slower the update
rate. The update rate can be calculated with the following equation:
PAL
Update rate (sec) = No. of cameras x Field delay
50
There are three main functions a multiplexer can achieve:
• Multiplex recording
• Multi-screen viewing
• Playback
Video multiplexers fall into two categories: Simplex and Duplex. A simplex multiplexer can
achieve only one of the above functions at once. For example, if live multi-screens are being
viewed, it is not possible to multiplex record or playback. Duplex multiplexers can achieve two
of the above functions simultaneously. For example, multi-screens can be viewed whilst
multiplex recording.
There are also semi-duplex multiplexers, such as the Sprite Lite DX4, which like a duplex
multiplexer, can achieve two functions simultaneously, but cannot multiplex record and
playback at the same time using two VCRs.
NTSC
No. of cameras x Field delay
60