Aladdin Digital Infrared Language Distribution
Installation and User Manual
Televic Conference Systems
2011-09-01
55
4.3.2.
Testing the Coverage Area
To make sure that the whole area is covered with
adequate IR radiation and avoiding thus black spots,
an extended reception quality test should be done.
The test can be done in two ways:
Testing During Installation
1.
Check that all radiators are connected and
powered up.
2.
Set the transmitter in the Test-mode (see
section 2.3.6). For each channel, a test tone
frequency will be transmitted.
3.
Set a receiver to the highest available channel
and listen to the received signal through the
headphones.
4.
Test all positions and directions (see next
paragraph).
Testing During a Meeting
1
．
Set a receiver in the Test-mode. The quality of
the received carrier signal is indicated on the
display of the receiver.
2
．
Test all positions and directions (see next
paragraph). The higher the value, the better
the signal.
Testing all Positions and Directions
Walk around the conference venue under the test
mode of the transmitter or the receiver; test every
position where the signal must be received. If an
area is detected as having bad reception or even no
reception at all, two main causes should be taking
into consideration:
Bad coverage
The receiver cannot pick-up adequate
infrared radiation. This may be because the
tested position is out of the footprint of
the installed radiators or the radiation is
blocked by obstacles such as a column, an
overhanging balcony or other large
objects.
Check whether you used the correct
footprints for the system design or not.
Check if the radiators used have a)
sufficient output power and b) are not
switched to half power operation by
mistake. If bad reception is caused by a
blocked radiation path, try to remove the
blocking obstacle or add an extra radiator
to cover the shaded area with more IR
energy.
Black spots
IR signals coming from two radiators may
cancel out each other (multipath effect)
when reaching the receiver. Bad reception
only happens on some special path.
Multipath effect is confirmed being the
cause of bad reception if the bad signal
received by the receiver is improving the
instant a radiator is a) changing its
direction b) shaded -off or simply
switched-off. IR radiation, reflected from a
surface with a high reflectivity may also
cause multipath effect.
Check that the signal delay compensation
switches on the radiators are set to the
correct value. Check the system design. If
necessary, reduce the distance between
the two radiators that cause the problem
and/or add an extra radiator.
Please note that due to the physical characteristics
of the signal distribution, it is not possible to avoid
multipath effects completely.
