I. Background and Introduction With the rapid development of technology, radio equipment and systems are undergoing tremendous changes. In addition to extensive use of digital equipment, the start, the system continuously to the network structure development.
Networked radio system that allows data acquisition, programming, and program broadcast a fundamental change in the exchange, so that broadcast model is more flexible, is simple, more secure and reliable system has greatly enhanced radio Radio in the media in an increasingly competitive environment, the status of the radio to bring greater development.
Henan People's Radio New Broadcasting House, completed in 2002,. With the completion of the new building, Henan People's Radio Broadcasting System on the comprehensive reform and upgrading. The new system architecture must have some leadership and advanced use of advanced technologies and programs to ensure the Henan People's Radio, the future development of space.
Through constant comparison and many discussions, the final choice of Henan People's Radio Network based on ATM technology-based radio station play the system. This is the most critical of the system and highlight the core technologies and features.
New radio broadcast network control system was built and put into use in 2003. The system includes seven sets of studio and broadcast system of total control. By the British Broadcasting System's network of AudixBroadcast digital broadcast console ADD9000, and digital audio broadcasting ATM network control system-ANTS.
System ATM network with the British Marconi Company's ASX-200BXATM switch as the core, were set up 11 ATM network nodes, 7 nodes are equipped with ATM network interface ADD9000 digital broadcast mixer, respectively, at 7 studio; four nodes is a different traditional ATM network digital audio interface audio conversion interface in total control room, for receiving external signals and external rotation transmission signal. Through the ATM network, seven studio and master control systems together into a whole. All the audio signal conversion in the network nodes into network signal into the ATM network to realize all of the audio signals on network management, deployment and routing control. In each network node, according to the need to extract the appropriate audio signal processing, signal conversion from the network became AES digital audio signals, used to connect other non-networked audio devices.
Entire network broadcast control system developed by the British AudixBroadcast ANTS management software to manage. This software is an integrated management system that can achieve a variety of ATM network management functions, but also can set all audio signals, scheduling and delivery, constitutes a complete radio broadcast control management system.
New system through a new radio broadcast and management, as well as stable and efficient system performance, the Henan People's Radio broadcast stations to provide a more varied way of broadcast, and effective programs to improve the quality and broadcast quality, making Henan People's Radio program to listen to keep on the enhanced radio in a highly competitive position in the market.
The system put into use three years from its stable performance and significant market success, fully proved ATM network in the field of application of radio station play's success.
Second, the system core technology-ATM network digital audio transmission technology
International professional audio engineers protocol (AES) after careful investigation and demonstration, launched in 2002, for digital audio transmission of the AES47 standard network. Full name is "AE47-2002: AESstandard for digital audio? Digital input-outputinterfacing? Transmission of digital audio over asynchronoustransfermode (ATM) networks". "AES47-2002: AES standard digital audio - Digital input / output interface mode - in the asynchronous transfer mode (ATM) networks to carry digital audio." This is the first web-based AES technology organization of professional audio transmission standard.
2.1 ATM Network ATM (Asynchronous TransferMode) in 1988 by the ITU-T (International Telecommunication Union Telecommunication Standardization Sector) for the telecommunications network to support broadband multimedia services and proposed a transfer mode, was recommended as the Broadband Integrated Services Data Network B-ISDN's information transfer mode and the foundation.
ITU definition of the ATM: ATM is Asynchronous Transfer Mode. Asynchronous refers to the statistical multiplexing nature of ATM. Transfer mode refers to the network used in the multiplexing, switching and transmission technology, which transfers information from one place to another transfer method used. In this transfer mode, information is organized into cell (CELL), all user information from a cell do not occur periodically. Thus, ATM is a cell in the network to the unit of statistical multiplexing and switching and transmission technology. Construction of the network using ATM technology called ATM transmission network, which is the channel from the VC-level network (or telecom network), VP-level access network and transmission network 3 composed of the media. In ATM mode, the network has multiple connectivity features, including support for radio (broadcast) type connections and multicast (multicast) type connectivity capabilities.
ATM is a new packet switching technology, the cell actually is a fixed-length packet, cell total length of 53 bytes, which is the letter of the first 5 bytes of header, 48 bytes of information section, or payload. Letterhead that cell fate contains the logical address, priority, flow control and error control information. ATM cell of the way to transfer information, and business characteristics, the bit rate has nothing to do with good data compatibility. Any business information, including voice, data and images, after cutting into a single package, after the format cell, can be transmitted in the network for transmission and switching. Method using asynchronous time division multiplexing
ATM, will come from different cell sources of information to bring together, within the buffer queue, the queue cell according to the sequence of arrival, by priority to the transmission line output one by one, from beginning to end phase of the cell stream. Sign the letter with the same element in the transmission line does not correspond to a fixed time slot, nor is there by cycle, avoiding the complex cell sequence control. Asynchronous time division multiplexing so that ATM has a great deal of flexibility, any business is the actual amount of information to take up resources so that maximum utilization of network resources. In addition, regardless of the nature of business how different sources (such as the rate of high and low, sudden size, quality, and how real-time requirements), networks are handled by the same model, the real