IEC 61603-3:1997 pdf download – Transmission of audio and/or video andrelated signals using infra-red radiation -Part 3: Transmission systems for audio signals for conference and similar systems

IEC 61603-3:1997 pdf download – Transmission of audio and/or video andrelated signals using infra-red radiation -Part 3: Transmission systems for audio signals for conference and similar systems.
This part of IEC 61603 gives methods for measuring and specifying those characteristics of audio infra-red (IR) transmission systems for conference and similar systems which are not covered by part I (see also 3.1), It allows systems which make different economic use of the available bandwidth to be described In order that conclusions regarding interference and compatibility can be drawn. Interface (matching) values and other system characteristics are also covered. The standard replaces chapter 2 of IEC 60764.
1.2 Normative references
The following normative documents contain provisions which, through reference In this text, constitute provisions of this part of BC 61603. At the time of publication, the editions indicated were valid All normative documents are subject to revision, and parties to agreements based on this part of IEC 61603 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 60068: Environmental testing
IEC 60268-15: 1996. Sound system equipment — Part 15: Preferred matching values for the interconnection of sound system components
IEC 6031 5-4: 1982, Methods of measurement on radio receivers tot various classes of emission – Part 4: Radio-frequency measurements on receivers for frequency modulated sound-broadcasting emissions
IEC 60417: 1973, Graphical symbols (or use on equipment – Index, survey and compilation of the single sheets
IEC 60764: 1983, Sound transmission using infra-red radiation
IEC 60914: 1 99,, Conference systems — Electrical and audio requirements
IEC 61147: 1993, Uses of infra-red transmission and the prevention o control of interference between systems
IEC 61603-1: 1997, Transmission of audio andor video and related signals using in (re-red radiation – Part 1: General
lEG 61938: 1996, AUdiO, video and audiovisual systems — Interconnections and matching values — Preferred matching values of analogue signals
ISO 7000:1989, Graphical symbols for use on equipment — Index and synopsis ITU-R 412.6: 1995, Planning standards for FM sound broadcasting at VHF
ITU-R 641:1990, Determination of radio-frequency protection ratios for frequency-modulated sound broadcasting
ITU-R 704: 1990, Characteristics of FM sound broadcasting reference receivers for planning purposes
1.3 DefinitIons
For the purpose of this part of IEC 61603, the definitions given in part 1 apply.
2 Explanation of terms and general InformatIon
2.1 Transmitter
A transmitter (link A-B in figure 2) has an audio signal input (analogue or digital). and a special form of electrical output to feed a radiator.
2.2 CombIned transmitter and radiator
A combined transmitter and radiator (link A•C In figure 2) does not have an electrical output. and interface values therefore apply only at the inp4it.
2.3 RadIator
A radiator (link B-C in figure 2) has a special form of electrical input, to be fed by a transmitter
A radiator may be combined with other functions, such as a transmitter. At present, radiators
normally Consist of a number (from ten and more) of Infra-red emitting diodes (IRED5)
employing different technologies. These devices have peak emissions in the wavelength
range 830 nm to 950 nm, and an IR bandwidth of about 100 nm.
2.4 Receiver
Besides the general characteristics given In part I and shown as link C’D In figure 2. others may need to be specified if a receiver is combined with other units to serve, for example. as a transmitter for up-stream signals in a duplex system.
To eliminate Interference from other modulated IR sources, the receiver shall provide enough selectivity with regard to the modulated subcarrier in addition to selectivity In the IR band. Normally, this selectivity shall correspond to the spectral bandwidth of the modulated subcarrier signal. with some margin for instabilities and possible extra features.
Definitions and methods of measurement for selectivity in relation to analogue FM signals are given in the standards dealing with FM broadcast systems, such as IEC 60315-4 and ITtJ-R 412, 641 and 704.
NOTE — For digdaJ audio Iransmieeion, the eubject 01 receiver seleclivly is erndw Consideration.
2.5 Ancillary equipment
Ancillary equipment. such as power supplies or battery chargers, may be required for the operation of the system. The manufacturer should specify all the data necessary for correct operation and maintenance.