Carriers And Channels; Aspects Of Ir Distribution Systems; Receiver Directional Sensitivity; Footprint Of The Radiator - Shure DT 6008 User Manual

DIS Digital Conference System

Carriers and channels

The DCS 6000 Digital IR system can transmit up to
8 different carrier signals (depending on the
transmitter type). Each carrier can contain up to 4
different audio channels.
The maximum number of channels per carrier is
dependent on the selected quality modes. Stereo
signals use twice as much bandwidth as a mono
signal, premium quality uses twice as much
bandwidth as standard quality. Per carrier a mix of
channels with different quality modes is possible, as
long as the total available bandwidth is not
exceeded.
The table below
combinations per carrier:
Mono
Conference
4
2
Possible
2
number of
channels
per carrier
Figure 0-D Possible channel combinations per carrier

Aspects of IR distribution systems

A good infra-red distribution system ensures that all
delegates in a conference venue receive the
distributed signals without disturbance. This is
achieved by using enough radiators, placed at well
planned positions, so that the conference venue is
covered with uniform Irradiation of adequate
strength.
There are several aspects that influence the
uniformity and quality of the infra-red signal, which
must be considered when planning an infra-red
radiation distribution system. These are discussed
in the next sections.

Receiver directional sensitivity

The sensitivity of a receiver is at its best when it is
aimed directly towards a radiator. The axis of
maximum sensitivity is tilted upwards at an angle
of 45 degrees (see Figure 0-C).
lists all possible
Channel Quality
Mono Stereo
Hi-Fi Conference
1
1
1 1
2
2
channel
Figure 0-C
Stereo Bandwidth
Hi-Fi
4 x 10 kHz
2 x 10 kHz and 1 x 20 kHz
2 x 10 kHz and 1 x 10 kHz (left) and 1 x 10 kHz (right)
1 x 20 kHz and 1 x 10 kHz (left) and 1 x 10 kHz (right)
2 x 10 kHz (left) and 2 x 10 kHz (right)
2 x 20 kHz
1 1 x 20 kHz (left) and 1 x 20 kHz (right)
Rotating
sensitivity. For rotations of less than +/- 45
degrees this effect is not large, but for larger
rotations the sensitivity will decrease rapidly.

Footprint of the radiator

The coverage area of a radiator depends on the
number of transmitted carriers and the output
power of the radiator. The coverage area of the
RA 6025 radiator is twice as large as the
coverage area of the RA 6013. The coverage area
can also be doubled by mounting two radiators
side by side. The total radiation energy of a
radiator is distributed over the transmitted
carriers. When more carriers are used, the
coverage area gets proportionally smaller.
The receiver requires a strength of the IR signal
of 4 mW/m2 per carrier to work without errors
(resulting in a 80 dB S/N ratio for the audio
channels). The effect of the number of carriers
on the coverage area can be seen in Figure 0-A
7
Directional characteristics of the receivers
the receiver will
User Manual
decrease the