1.3 System technology
1.3.1 Basic system concept
The system composition of one digital infrared wireless
conference combo unit, one digital audio power
amplifier and digital infrared wireless conference units:
The digital infrared wireless conference combo unit
receives infrared signals from every digital infrared
wireless conference unit and converts the signals into
audio which is transmitted to the digital audio power
amplifier, or into control signals which are convert into
carrier outputs and transmitted to the digital infrared
conference units.
1.3.2 IR radiation
Audio and control signals of HCS-5335 are transmitted
as modulated infrared light. Infrared radiation is part of
the electro-magnetic spectrum, which is composed of
visible light, radio waves and other types of radiation.
Its wavelength is longer in comparison with the
wavelength of visible light.
Infrared light cannot pass through opaque walls and
ceilings and therefore guarantees privacy of the
meeting by avoiding of being intercepted or disturbed.
In addition, infrared light has no radio radiation and a
license is not required when operating infrared light
systems.
1.3.3 Aspects of infrared signal transmission
Just like visible light, infrared radiation is reflected from
hard surfaces and refracted by hyaloid (glassy or
transparent appearance) items. Objects in the
conference venue as well as structure of the walls and
ceilings will influence the distribution of infrared light.
Infrared radiation is reflected from almost all hard
surfaces. Smooth, bright or shiny surfaces reflect well.
Dark or rough surfaces absorb a large part of the
infrared energy. Usually, surfaces opaque to visible
light are also opaque to infrared radiation.
Shadows from walls and furniture will influence the
transmission of infrared light. This can be solved by
using a sufficient quantity of transceivers. They should
be positioned in a manner to provide an infrared field
strong enough to cover the whole conference area.
1.3.4 Carriers and channels
TAIDEN HCS-5335 compact digital infrared wireless
conference system adopts 1~6 MHz wave band (IEC
61603 BAND
Ⅲ
,
Ⅳ
), shown as figure 1.2.. And the
Channels and corresponding frequencies
refer to table
1.1.
Figure 1.2 Standard wave band in HCS-5335 system
Route
Channel
Frequency
From conference
unit(s) to combo
unit
Audio channel 1
1.8 MHz
Audio channel 2
2.3 MHz
Control channel
2.8 MHz
From combo unit
to conference
unit(s)
Control signal
3.3 MHz
Table 1.1 Channels and corresponding frequencies in
HCS-5335 system
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