Bosch Appliances 3122 475 22015en manual Aspects of infra-red distribution systems

INTEGRUS Installation and User Instructions System description and planning en 3

1.2.4 Carriers and channels

The Integrus system can transmit up to 8 different car- rier 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 sig- nals use twice as much bandwidth as a mono signals, 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 band- width is not exceeded. The table below lists all possible channel combinations per carrier:

45

45

90

Figure 1.4 Directional characteristics of the receivers

Possible

number of

channels

per carrier

	Channel quality
Mono	Mono	Stereo	Stereo	Bandwidth
Standard	Premium	Standard	Premium
4				4 x 10 kHz
2	1			2 x 10 kHz and 1 x 20 kHz
2		1		2 x 10 kHz and 1 x 10 kHz (left) and 1 x 10 kHz (right)
	1	1		1 x 20 kHz and 1 x 10 kHz (left) and 1 x 10 kHz (right)
		2		2 x 10 kHz (left) and 2 x 10 kHz (right)
	2			2 x 20 kHz
			1	1 x 20 kHz (left) and 1 x 20 kHz (right)

1.3Aspects of infra-red 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 IR- radiation of adequate strength.

There are several aspects that influence the uniformity and quality of the infra-red signal, which must be con- sidered when planning an infra-red radiation distribu- tion system. These are discussed in the next sections.

1.3.1Directional sensitivity of the receiver

The sensitivity of a receiver is at its best when it is aimed directly towards a radiator. The axis of maxi- mum sensitivity is tilted upwards at an angle of 45 degrees (see figure 1.4). Rotating the receiver will decrease the sensitivity. For rotations of less than +/- 45 degrees this effect is not large, but for larger rotations the sensitivity will decrease rapidly.

1.3.2 The footprint of the radiator

The coverage area of a radiator depends on the num- ber of transmitted carriers and the output power of the radiator. The coverage area of the LBB 4512/00 radiator is twice as large as the coverage area of the LBB 4511/00. 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 1.5 and figure 1.6. The radiation pattern is the area within which the radiation intensity is at least the minimum required signal strength.

Bosch Security Systems 2005-04 3122 475 22015en