Black Spots; Interference From Ir Systems - Danish Interpretation Systems DCS 6000 User Manual

DIS
The receiver picks-up IR signals from two
3.6.5

Black spots

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.
Black spots can occur in case a transmitter is
located in the same room as the radiators. In that
case, disable the mini IR radiator of the
User Manual DCS 6000 Digital IR System rev H.docx
transmitter with the configuration menu (see
section 2.5.16).
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.
IR assistive hearing systems and IR microphones
3.6.6

Interference from IR systems

operating at frequencies above 2 MHz can
disturb the reception at the lowest carriers. If
such is the case, disable the lowest two carriers
(see section 4.5.11) and re-check the reception.
User Manual
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