WIRELESS TRANSMISSION METHODS FOR AUDIO SIGNALS IN PUBLIC ADDRESS (PA) SYSTEMS
Abstract
The demand for flexible and reliable audio solutions has driven the adoption of wireless technology in public address (PA) systems. However, many existing solutions suffer from significant trade-offs, including limited operational range, audible latency, poor audio fidelity, and low power efficiency, especially in the low-to-mid cost segment. This project aimed to address these limitations by designing and constructing a fully integrated 60W wireless public address system, with a specific focus on optimizing the wireless transmission method for robustness and high-quality audio delivery.
The design process involved a comparative analysis of wireless technologies, leading to the selection of a 2.4 GHz Digital Spread Spectrum (DSSS) transceiver module for its optimal balance of range, latency, and interference immunity. A high-efficiency Class-D amplifier circuit was designed around the TPA3116D2 integrated circuit to provide powerful audio amplification. The system was realized through careful schematic capture, PCB layout prioritizing signal integrity and electromagnetic compatibility (EMC), and systematic integration of all subsystems.
Rigorous testing of the constructed prototype demonstrated a maximum wireless range of 45 meters in an open field with an exceptionally low latency of 18.5 milliseconds, making it suitable for real-time speech reinforcement. The amplifier delivered 55 watts of output power into a 4-ohm load with a total harmonic distortion (THD) of less than 0.1% and a peak efficiency of 86.6%. These results confirm the successful development of a cost-effective system that effectively merges robust wireless audio transmission with high-fidelity, high-power amplification, fulfilling a recognized gap in the market and providing a solid foundation for future development and potential commercialization.
Keywords: Public Address System, Wireless Audio, Class-D Amplifier, 2.4 GHz Transmission, Total Harmonic Distortion (THD), Latency, Efficiency.
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