Outdoor Public Address Systems
The outdoor public address systems can be divided into the following categories according to transmission and signal processing:
1. Traditional outdoor public address systems: the outdoor public address system is transmitted to the terminal loudspeaker through the audio line. The power amplifier of the machine room to the loudspeaker is high level, usually 100V or 70V. The advantage is that the loss of the line is less, the load connection is convenient, and it only takes the step-down transformer. The loudspeaker is connected to the line on the road.
2. Digital addressable outdoor public address systems: real digital addressable public address system, its audio signals, control signals and communications are all carried out in the digital domain, with a far greater transmission distance and better transmission effect, especially the transmission of audio and control signals on a twisted pair of two cores. It greatly saves the cost of installation and wiring, and provides a precondition for future system maintenance and high reliability of the system.
3. Streaming media (IP) intelligent outdoor public address systems: streaming media (IP) intelligent digital address is a pure digital network audio broadcasting system based on the Internet and LAN. It is different from the traditional analog audio, FM, addressing and CNC broadcasting systems. The streaming media (IP) intelligent digital address system is fully compatible with the present Internet and LAN, the application of TCP/IP protocol, without any other wiring, can use the existing campus network or internal LAN; embedded hardware terminal, can set independent IP address, through a multi-layer switch, through the host can control the settings and playback of each terminal, more can be selected on the terminal needs. Because of the use of computer technology, the system can almost be compatible with all audio formats, using the IP technology, the content of the program can be played without any restrictions, each terminal can play the desired program content as he wants. It can completely replace the traditional intelligent address system based on analog or digital, and truly realize the IP audio broadcasting function based on the Internet or LAN. It supports broadcasting, live broadcast, on demand and so on, and also supports a wide range of popularization and application.