Signal Processing
The Integrus system uses high frequency carrier signals (typically 2-8 MHz) to prevent
interference problems with modern light sources (see section The footprint of the radiator,
page 23). The digital audio processing guarantees a constant high audio quality.
The signal processing in the transmitter consists of the following main steps (see the next
figure):
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.
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 convert the carrier signals to modulated infrared light.
In the IR receivers a reverse processing is used to convert the modulated infrared light to
separate analogue audio channels.
Figure 4.2: Overview of the signal processing (for one carrier)
Quality modes
The Integrus system can transmit audio in four different quality modes:
– Mono, standard quality, maximum 32 channels
– Mono, premium quality, maximum 16 channels
– Stereo, standard quality, maximum 16 channels
– Stereo, premium quality, maximum 8 channels
The standard quality mode uses less bandwidth and can be used for transmitting speech. For
music the premium quality mode gives near CD quality.
4.1.2
4.1.3
Language Distribution System Planning | en 21
Bosch Security Systems B.V. Operation manual 2013.11 | V1.4 |
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