IEC 61603-3:1997

Overview

IEC 61603-3:1997 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies requirements and measurement methods for audio infra-red (IR) transmission systems used in conference and similar applications. This part 3 of the IEC 61603 series focuses exclusively on the transmission of audio signals via infra-red radiation, complementing other parts that cover video and related signals.

Its primary goal is to provide clear guidelines for designing, testing, and specifying IR audio transmission systems to ensure reliable, high-quality performance in professional conference sound systems and similar environments. The standard supersedes earlier IEC 60764 chapter 2 and is intended for use by system developers, manufacturers, and installers of audio IR equipment.

Key Topics

Scope and Application

• Defines the methods for measuring key characteristics of IR audio transmission systems not addressed in Part 1.
• Applies to systems in conference rooms, meeting spaces, and other environments where wireless IR audio communication is needed.
• Covers system planning, installation considerations, and functional partitioning among components.

Technical Requirements

• Characteristics of IR sources: Defines parameters such as spectral output and signal modulation for IR transmitters.
• Receiver characteristics: Measurement methods for sensibility, signal-to-noise ratio, and channel discrimination of IR receivers.
• Interface values: Specifies electrical interface levels for transmitter outputs and receiver inputs to ensure system compatibility.
• Polarity and signal integrity: Guidelines on maintaining proper polarity and minimizing spurious emissions.
• Channel allocation and modulation: Recommendations for frequency assignments, subcarrier channels, and modulation techniques to avoid interference.

Measurement and Testing

• Establishes general conditions for measurement to ensure consistent results across different test environments.
• Provides detailed methods to evaluate system parameters, enabling manufacturers and users to verify conformity with performance standards.

Marking and Documentation

• Specifies the marking requirements for devices and components, including frequency and channel identification.
• Recommends content for technical specifications, aiding transparency in product data sheets.

Applications

IEC 61603-3 standard finds practical usage in diverse areas where high-quality wireless audio transmission is critical:

• Conference systems: Facilitates clear, interference-free audio transmission for multi-channel conference setups.
• Hearing assistance systems: Supports IR transmission in assistive listening devices commonly deployed in auditoriums and public venues.
• Corporate meeting rooms: Enables flexible and wireless audio distribution without risk of RF interference.
• Broadcast and media production: Used where reliability and audio fidelity are essential, and wired connections are impractical.

Adoption of this standard ensures interoperability between components manufactured by different suppliers and enhances system reliability and user experience.

Related Standards

IEC 61603-3 is part of the broader IEC 61603 series on infra-red transmission systems for audio and video signals:

• IEC 61603-1: General principles for audio/video IR transmission.
• IEC 61603-2: Transmission systems for wideband audio and related signals.
• IEC 61603-4 to 6: Cover low/high-speed remote control systems and high-quality audiovisual IR transmission.

Additionally, practitioners are encouraged to consult:

• IEC 61147: Technical report associated with audio and multimedia systems.
• IEC 60050: International Electrotechnical Vocabulary for standardized terminology.
• IEC 60027, 60417, and 60617: For graphical and letter symbols used in electrical and electronic equipment.

By following IEC 61603-3:1997, manufacturers and integrators of infrared audio systems for conferences and similar environments can achieve standardized, high-performance transmission solutions that meet international quality and compatibility benchmarks.