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New trend for PA system - Networking, Wireless and High Definition

Date:2016年6月13日 14:28

Public Broadcasting System (referred to PA) is a self-managed use of units, within the scope of the construction business and emergency broadcast to the public, and to provide background music system. Currently, public broadcasting has shown a good momentum of development. Main features: market demand for more and more and more complex functional requirements; broadcast production innovation capability of enterprises continued to improve, more humane products.

As technology develop rapidly, belong to the category of electro-acoustic public address and sound reinforcement systems have been considerable development, but their development has different features: professional sound system generally based on electro-acoustic performance of the division level, while public broadcasting should be prepared according to the main functions and speech intelligibility division level. In recent years, public broadcasting system, showing networking, wireless and high definition of the development of new trends


1. Public broadcasting network development trend

Recently many indications: Public broadcasting has entered the network age

Typical network broadcasting system is based on IP data transmission network audio sound system, it may be in the same local area network or across the Internet Internet use within the LAN gateway, into a TCP / IP network protocol broadcast systems based DSPPA it is an application, and CobraNet dedicated private network broadcasting system comparison flexibility. CobraNet network broadcasting system is an integrated hardware, software and communication protocols for the integration of real-time network audio transmission technology, it can guarantee the quality of the audio transmission, but is limited by expensive and cumbersome equipment line, lack of flexibility. A typical system consists of a broadcast network broadcast network control center, network terminals, network paging microphone, fire network interfaces and other components. Break through the traditional system of public broadcasting only under a centralized control can only pass and disadvantages from the engine room, interactive features strong, zoning and grouping can be any combination of control, can achieve long distance transmission over the network. If the typical network broadcast system combines safe city and banks and other terminal intercom system can implement application specific extensions

Network broadcasting system is generally applicable to a large area of large commercial buildings, schools (University City), buildings, airports, railway stations, urban area and other occasions. Shanghai World Expo is the use of network broadcasting system, according to the land, area, national venues multilevel priority setting, which saves cost, easy to manage. Topology shown in Figure 1, Figure 2. The current standard of public broadcasting frequency mainly by the Chinese Institute of Electronics Engineering Branch of acoustic and Sound Technology Co., Ltd. Guangzhou DSPPA editor of "Public Broadcasting System engineering and technical norms" GB50526-2010, at home and abroad are still no specific standards for the public broadcasting network and norms.

Broadcast network design points to note:

1) should effectively understand the needs of consumers, and to avoid the use of digital and public broadcasting network, a waste of investment;

2) network system design parameters understanding of the project to be constructed, it is determined that the use of high-quality security CobraNet network or convenient, low-cost TCP / IP networking, determine the opening of multicast protocols;

3) Depending on the project according to the needs of classification set priorities, flexible networking.


2. Radio appears

During the "Eleventh Five-Year "national public emergency system construction plan" put forward: "Strengthening early warning systems and early warning information release platform, to build all kinds of public emergencies public information release channels, improve the whole society, especially in remote mountainous areas , rural and other information at the end of early-warning capabilities to address the warning information release last kilometer bottleneck problem. " Country attaches great importance to this one broadcasting system applications, therefore, the lifting cable "bond" on-demand radio was born.

Before several provinces in the "village" and "sound village" project, carried out some useful exploration, it has a lot of valuable experience and success stories. Each existing broadcasting platforms, including cable television, FM radio technology is mature, fully able to meet the application needs of rural emergency broadcast. Rural radio system most of the time used by the towns, villages and other grass-roots level. Backbone network using wireless FM transmission and the terminal of cable coverage combination of approaches, both good solution to the problem of full coverage, but also to achieve multi-level interaction manageable and controllable. In the event of such a large earthquake is similar to natural disasters, the final valid or FM broadcast technology. Make full use of the existing backbone network radio and television networks can save and invest, without additional wiring maintenance, conservation of resources and late fees

Radio during the fight against natural disasters, the role is irreplaceable, it can be quickly evacuated, directing relief work. Since the technology is mature, medium difficulty, radio system extensions or modifications are also many applications

Sichuan county "villages" system is a typical case of radio broadcasting system. Its design with simple, advanced and reliable principle, do not use a lot of equipment in case of the completion of the multi-level addressable linkage function, county, township and village levels compatible with the ability of linkage. The use of county-level radio station platform to host multi-function control center, the radio station signal, emergency broadcast microphone signal, GSM wireless networks, telecommunication lines and other types of emergency signal into the control panel by setting priorities to achieve the various types of signals hierarchical priority control. It will advance the various government departments in the emergency telephone numbers provided to the control panel and set its separate password. Required release emergency broadcasting, you only need to dial a phone number or an emergency control panel wired phone number, you can implement the relevant operation according to Chinese voice prompt content. By phone broadcasting can achieve the partition selection, direct broadcast or publish voice alarm signal, perform a pre-event. In broadcasting the emergency control room can be directly controlled by the host computer to control some of the major functions and partition selection.

The township's wireless FM transmitter transmit signals to each administrative village. In a broadcast multi-function controller-based, emergency radio signal from the county removed from the closed-circuit television system, an emergency signal from the microphone, external CD / DVD audio, computer audio signal and control data signals, GSM cell phone signal reception, etc. all into the multipurpose controller. After mixing inside the controller hardware and program prioritization process. Audio signals and control signals via a dedicated audio Optical transmitter into the high mountains, and finally to all administrative villages through a transmit antenna

Administrative villages have local broadcast function, can receive the emergency broadcast signal towns and counties. 5, constituting the system is relatively simple, with a single addressable broadcast control terminal as the center, comes with 120W constant pressure amplifier, can simultaneously connect four 25W High Definition horn speakers. Usually publish daily local broadcast when there is an emergency broadcast superiors publish, automatically converted to receive broadcast signals broadcast superiors. At the same time the system configuration set UPS power supply, even when utility power is out for a long time it can also be an emergency broadcast.

Jiangxi Province is located in the East Asian monsoon region, terrain and complex geological conditions, the special climatic conditions and the uneven spatial and temporal distribution of precipitation, easy to form a local heavy rainfall, leading to flash floods disasters, the province many counties included in the national non-county mountain flood prevention works building measures. Non-engineering measures for mountain flood prevention in the county through the establishment of monitoring systems covering torrential rainstorm and flood-prone areas, information transmission and reception system, early warning information service system, rural end early warning systems and monitoring and prevention system, improve the existing mountain flood defense system, effectively reduce the loss of flash floods disasters. By design, the village in the mountain flood-prone area of the construction of the main radio stations, villages and group building its jurisdiction radio sub-station. Master station can send warning centers by receiving warning information transmitted by radio to the master warning area sub-stations, loudspeakers broadcast to all households.


3. High-definition broadcasting system development trend

For a long time, sound clarity station broadcasting system is poor, many people could not hear a noisy time. With the rapid development of railway technology, railway transport railway ancillary equipment requirements are also increasing. The original radio system can not meet the new requirements to the Hankou Railway Station broadcasting system, for example, the main manifestations

Ceiling / wall / floor / column is not for acoustic treatment;

Space station Volume: 138m (L) × 64 m (W) × 18 m (H);

Reverberation time up to 7.6S, 200Hz standing serious;

In a passenger when the ambient noise of up to 75dB.

To build such a complex acoustic environment, sound broadcasting has not been satisfactory, the Ministry of Railways leadership considered it necessary to improve the system sound applications in broadcast stations, high-definition requirements.

Definition PA system is sound clarity of speech transmission index system (STIPA), "Public Broadcasting System engineering and technical norms" Article 2.0.29 This is made clear explanation: STIPA is a simplified form of speech transmission index, with the PA system for objective evaluation (including public broadcasting system) of speech transmission quality. And 3.3.1 lists the public broadcasting electro-acoustic performance levels. STIPA can be measured by the relevant instruments. Figure 7 shows a definition of sound HD STIPA value must be greater than or equal to 0.80.

Demand for high-definition reality, well-known manufacturers in the single speaker, speakers aspect developed a highly directional, high-power, high-sensitivity full-band, band attenuation is slow, high-definition language (STIPA up to 0.88) or high definition remote ceiling speakers remote horn speakers, plus cabinet narrow frame, streamlined appearance and other modifications to meet the high requirements of the occasion, bringing high-definition sound experience. In some large public broadcasting hall, exhibition on the application, there have been small (micro) line array speakers and flat line array shown in FIG. 8, the high sensitivity of such products, strong direct sound good effect, while easy construction installation

Another method is a high-definition sound reinforcement phased array technology, China broadcast this unique technology. 9, the use of phased array sound column as shown in digital processing (DSP) technology can be virtual directivity characteristics different shapes sound column, and other properties of the sound column itself is not affected, the adverse conditions suitable for architectural acoustics [large volume of space, Acoustical conditions are poor, long reverberation time and sound turbidity] halls, stadiums PA, with the remote control or computer remote control to achieve accurate sound coverage useful areas auditorium etc., and inhibit its spread to unwanted areas, reduce acoustic renovation stadium PA system power consumption and investment.

Phased Array speaker has a wide range of applications, such as Karamay Convention Exhibition Center equipment flat line array speakers; Guangdong Science Center Phased array column sound perfectly adapted to the environment and so to build sound complex.


4. Conclusion

Public broadcasting network rendering, wireless, high-definition trend is the result of market demand and technological development of common birth, which also contributed to the development of public broadcasting technologies in our country.

TypeInfo: Industry News

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