GB/T 34999-2017 in English

Background of Standard Formulation and Analysis of Technological Evolution

With the rapid development of digital technology, the broadcasting industry has increasingly higher requirements for audio quality. This standard is based on the technical foundation of GY/T158—2000 "Studio Digital Audio Signal Interface" and combines the international standard IEC 61606 series to formulate detailed technical requirements and measurement methods for the specific needs of digital audio recording systems in broadcast centers.

In terms of technological evolution, this standard focuses on solving the signal fidelity problem of digital audio systems during transmission, processing and recording, and especially proposes clear technical indicators in terms of quantization bits, dynamic range and distortion control. At the same time, the standard also takes into account the interoperability of equipment and the uniformity of test conditions to ensure that equipment produced by different manufacturers can be compatible and meet broadcast quality requirements.

Comparative Analysis of Standard Frameworks

Test Instruments and Conditions

Test instrument requirements include:

• Signal Generator: Frequency error ≤±0.05%, amplitude error ±0.01 dB.
• Signal Analyzer: Filter characteristics must comply with GB/T3241-2010 requirements, and the level meter accuracy is ±1% or less than 1/2 LSB.

Test conditions include ambient temperature (15°C~35°C), relative humidity (45%~75%), and power supply parameters (220V±22V, 50Hz±2Hz). All measurements must be performed under standard settings to ensure that the equipment gain controller is adjusted to a flat frequency response state.

Implementation Suggestions

1. Follow the interface requirements in the standard, and give priority to the XLR balanced interface and BNC unbalanced interface specified in GY/T158-2000.
2. In system design, ensure that the gain controller, equalizer and other audio processing modules are in the factory recommended settings.
3. Regularly calibrate the test instrument to ensure that the measurement accuracy meets the standard requirements (such as the level meter accuracy is at least 0.25 dB).
4. For multi-channel equipment, perform channel characteristic tests one by one and record the maximum gain difference and phase difference.