Signal Processing; Quality Modes - Danish Interpretation Systems DCS 6000 User Manual

DIS
light, radio waves and other types of radiation. It
has a wavelength just above that of visible light.
Like visible light, it is reflected from hard
surfaces, yet passes
materials such as glass.
The infra-red radiation spectrum in relation to
other relevant spectra is shown in Figure 3.2-A.
1 Daylight spectrum
2 Sensitivity of the human eye
3 IR radiator
4 Sensitivity of IR sensor
5 Sensitivity of IR sensor with daylight filter
Figure 3.2-A Infra-red radiation spectrum in relation to other
spectra
The DCS 6000 Digital IR system uses high
3.2.2

Signal Processing

frequency carrier signals (typically 2-8 MHz) to
prevent interference problems with modern
light sources (see section 3.3.3). The digital
audio processing guarantees a constant high
audio quality. The signal processing in the
transmitter consists of the following main steps
(see Figure 3.2-B):
1. A/D conversion - Each analogue audio
channel is converted to a digital signal.
2. Compression - The digital signals are
compressed to increase the amount of
information that can be distributed on each
carrier. The compression factor is also
related to the required audio quality.
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User Manual DCS 6000 Digital IR System rev H.docx
3. Protocol Creation - Groups of up to four
digital signals are combined into a digital
information stream. Extra fault algorithm
information is added. This information is
used by the receivers for fault detection and
correction.
4. Modulation - A high frequency carrier signal
is phase-modulated
information stream.
5. Radiation – Up to 8 modulated carrier
signals are combined and sent to the IR
radiators, which convert the carrier signals
to modulated infra-red light. In the IR
receivers a reverse processing is used to
convert the modulated infra-red light to
separate analogue audio channels.
In the IR receivers a reverse processing is used
to convert the modulated infra-red light to
separate analogue audio channels
The DCS 6000 Digital IR system can transmit
3.2.3

Quality modes

audio in four different quality modes:
Mono, conference quality, maximum 32
channels (standard quality)
•
Mono, Hi FI quality, maximum 16
channels (premium quality)
•
Stereo, conference quality, maximum 16
channels (standard quality)
•
Stereo, Hi FI quality, maximum 8
channels (premium quality)
•
The conference quality
bandwidth and can be used for transmitting
speech. For music the HI-FI quality mode gives
near CD quality.
User Manual
with the digital
.
mode uses less
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