Installation Guide Part 3

NGL FX Installation Manual Rev. * 70 of 84
Table 9: Sync Indicators
Board
Selection
External
Sync
Source
DS3
(Master)
Green
DS9
(Submaster)
Yellow Pedestal Lights Description
Master Absent On Off - Self generating sync, no external
sync pulse received. (Normal)
Master Present Off Blink - Master is receiving an external
sync pulse. When this occurs the
master becomes a submaster.
(Abnormal)
Submaster Absent Blink Blink On
(This is the default
indication and can be
changed using SAM)
Submaster either lost or never
received external sync pulse.
Report this error by System Event.
(Error)
Submaster Present Off On - Submaster is receiving an external
sync pulse. (Normal)
DC Power Indicator (DS13)
DS13 on the Main PCB will illuminate when 24VDC is applied to the board at terminals J18 or
J31.
Noise Sources
There are generally two different types of noise sources our systems can encounter; asynchronous
and synchronous.
Asynchronous noise is random in nature and is found through out the frame (signal and noise
channel) when certain devices are at close proximally to our system. These sources could reduce
detection and in some cases cause false alarming. Asynchronous noise sources could be the
following:
1. CW Sweeper – These devices sweep through out detection band causing loss of detection
and false alarming. They usually have a constant linear sweep rate (100Hz to 200Hz)
with a certain high and low frequency range and a constant signal level.
2. Spiky Noise – This is usually from automatic door motors, (broken) lighting ballasts and
other pulse listening systems not synchronize to our system.
Synchronous noise is associated with items in close proximally to our system which resonate
during our transmission cycle and look like a tag ring down to our system. These items are more
of a false alarm threat when compared to asynchronous noise especially if the item is moving.
They could also affect detection because of the complex mixing of the intended tag signal and
offending resonance. Synchronous noise sources could be the following:
1. Automatic Door Frames – In some cases metal doors will resonate and cause an emission
much like a tag ring down. When the door opens and closes, the background subtraction
feature could be defeated causing false alarms.