Testing The Coverage Area - Bosch INTEGRUS Installation And Operating Manual

INTEGRUS | Digital Infra-red Language Distribution System

1.6 Testing the coverage area

An extensive reception quality test must be done to make sure that the whole area is covered with IR radiation of adequate
strength and that there are no black spots. Such a test can be done in two ways:
Testing during installation:
1. Check that all radiators are connected and powered up and that no loose cables are connected to a radiator. Switch the
transmitter off and on to re-initialise the auto equalisation of the radiators.
2. Set the transmitter in the Test-mode (see section 2.5.7). For each channel, a different test tone frequency will be
transmitted.
3. Set a receiver on the highest available channel and listen via the headphones to the transmitted test tone.
4. Test all positions and directions (see next paragraph).
Testing during a meeting:
1. Set a receiver in the Test-mode and select the highest available carrier. The quality of the received carrier signal is indicated
on the display of the receiver (see section 4.3).
2. Test all positions and directions (see next paragraph). The quality indication should be between 00 and 39 (good reception).
Testing all positions and directions
With the transmitter and receiver in one of the two test modes, go around the conference hall and test the reception quality at
every position where the infra-red signals must be received. When an area is detected where there is bad reception or even no
reception at all, two main causes must be considered:
Bad coverage
The receiver can not pick-up infra-red radiation of adequate strength. This can be because the tested position is outside 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 that you used the correct footprints for the system design, that radiators with enough output power are installed and that
a radiator is not accidentally switched to half power operation. When the 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.
Black spots
The receiver picks-up IR signals from two radiators which cancel out each other. The multipath effect can be identified by the
observation that the bad reception only occurs along a specific line and/or when good reception returns when the receiver is
rotated to another direction. This can be confirmed by keeping the receiver in the position and direction with the bad reception
and then either shading-off the radiation from one radiator with your hand or switching off one radiator. If this improves the
reception quality, then the multipath effect is causing the problem. Note that IR radiation that is reflected from a surface with a
high reflectabiliy can also cause multipath problems.
Check that the signal delay compensation switches on the radiators are set to the correct value and that a switch is not
accidentally positioned between two numbers. Re-check your system design. When necessary, reduce the distance between the
two radiators that cause the problem and/or add an extra radiator.
Note that due to the physical characteristics of the signal distribution, it is not always possible to completely avoid multi path
effects.
BOSCH Security Systems | February 2003
en |
21