Signal Processing; Quality Modes - Shure DT 6008 User Manual

DIS Digital Conference System

Signal Processing

The DCS 6000 Digital IR system uses high
frequency carrier signals (typically 2-8 MHz) to
prevent interference problems with modern light
sources (see section 'IR radiation'). The digital
audio processing guarantees a constant high audio
quality. The signal processing in the transmitter
consists of the following main steps (see Figure
0-B):
1. A/D conversion - Each analogue audio channel
is converted to a digital signal.
2. Compression -
compressed to
information that can be distributed on each
carrier. The compression factor is also related to
the required audio quality.
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 with the digital information
stream.
5. Radiation – Up to 8 modulated carrier signals
are combined and sent to the IR radiators, which
Audio
Channel
4x
Audio
Channel
Figure 0-B Overview of the signal processing (for one carrier)
The digital signals
increase the amount
A/D Conversion
& Compression
4x
A/D Conversion
& Compression
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 .

Quality modes

The DCS 6000 Digital IR system can transmit
audio in four different quality modes:
are
•
of Mono, conference quality, maximum 32
channels (standard quality)
•
Mono,
channels (premium quality)
•
Stereo, conference quality, maximum 16
channels (standard quality)
•
Stereo,
channels (premium quality)
The conference
bandwidth and can be used for transmitting
speech. For music the HI-FI quality mode gives
near CD quality.
Protocol Creation
& Modulation
6
Hi FI quality, maximum
Hi FI quality, maximum
quality mode
Carrier (to IR Radiators)
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