What are the advantages and disadvantages of the four transmission methods of campus broadcasting system?
The campus broadcasting system is an important hardware infrastructure of schools. With the development of technology, the development of campus broadcasting has gone through several generations of products, which can be divided into transmission methods: audio wired constant voltage (constant resistance) transmission, wireless frequency modulation transmission wired frequency modulation transmission, and digital IP network transmission. Next, let me tell you about the advantages and disadvantages of each of these four transmission methods.
① The most common is wired constant voltage audio twisted pair transmission: its advantages are cheap terminals and simple structure; The disadvantage is that each classroom requires wiring, and the system is strictly configured according to the principles of power matching and impedance matching. It has poor scalability and cannot achieve stereo broadcasting. The program capacity is small (only one set of programs can be transmitted), and it cannot simultaneously broadcast different content according to grade level.
② Wireless FM transmission method: Its advantages are simple construction, no need for wiring, low cost, and the ability to achieve simultaneous broadcasting of multiple channels; The disadvantage is that it requires space and frequency resources, and in principle, it needs to be approved by the radio management department. It is susceptible to external interference and has relatively poor reliability.
③ Wired coaxial cable frequency modulation transmission method: Wired frequency modulation is based on the frequency division multiplexing technology of cable television coaxial cable transmission method. Its advantages are that it can achieve simultaneous transmission of multiple channels, strong scalability, and terminal speakers only need to meet the receiving level, without being limited by quantity or power. Cable TV technology in China has gone through nearly 20 years of development history and is fully mature. Its supporting products are affordable and have stable performance. Cable FM broadcasting can be transmitted through cables with closed-circuit VOD, dual control, and closed-circuit television, without the need for wiring, with simple construction, expandable number of transmitted programs, and intelligent broadcasting addressable control function; The disadvantage is that the wired frequency modulation transmission method is based on weak signal transmission, and the frequency modulation speaker requires an external 220V AC power supply. Each school classroom can provide a stable 220V AC power supply.
④ The IP network broadcasting system is based on the widely used Ethernet network platform, making full use of the network platform, such as campus LAN, which does not require wiring and is completely different from products such as pure analog broadcasting, FM addressed broadcasting, and CNC broadcasting. It combines multiple digital audio technologies and demonstrates its significant superiority in many aspects. The audio transmission distance is infinitely extended and can run on cross gateway local area networks and the Internet, supporting a wide range of important applications. It centrally controls broadcasting from the main campus to branch campuses, and simultaneously broadcasts from the company headquarters to various regional branches, achieving fast and reliable information communication. It can simultaneously broadcast different programs to multiple terminals, which not only fully realizes the functions of traditional broadcasting systems, but also has multiple functions such as file on-demand, USB playback and recording, and two-way intercom between terminals.
IP broadcasting is superior to previous generations of broadcasting systems in terms of transmission distance, sound quality, diversified functions, safety and reliability, personalized terminals, easy maintenance, simple engineering, and networked management.
