【 Weak current College 】 public broadcasting system (2)---Power By 【 China power house network 】

Public broadcasting's design and selection

First, the public broadcasting system of classification
Modern buildings of the public broadcasting system according to the nature of building size, use and function requirements can be divided into the following three types:
⑴ the business of broadcasting system.
⑵ service broadcasting system.
⑶ fire broadcasting system.
1. the business of broadcasting system: office buildings, commercial buildings, schools, hospitals, rail stations, airports, stations, banks and factories, and other buildings set business of broadcasting, to meet the operational and administrative requirements of business broadcasting.
2. service broadcasting system: Hotel, hotels, shopping malls and entertainment facilities and large public places set service broadcast, service broadcasting range is the background music and Guest programme broadcasting, aims to offer an appreciation of music radio program, to serve as principal objects., such as service hotel broadcasts four sets of general elections. Broadcast content arrangement should be based on the service object and project level.
3. fire broadcasting system: mainly used for fires, fire control, fire service personnel from fire radio guide people to quickly evacuate the dangerous places.
Second, the design of public broadcasting
1. public broadcasting's design based on the following criteria
(1) industry standard to the people's Republic of China civil construction electrical design code JGJT-16-92.
(2) the national standards People's Republic of China automatic fire alarm system design code GBJ/16-88.
2. the composition of the public broadcasting system
Public broadcasting system is mainly composed of signal source, power equipment, monitoring equipment, control equipment, fire radio control equipment, the user equipment and broadcasting transmission lines.
3. the public broadcasting system design
⑴ transmission mode: System output powerfeed delivered by cable way.
⑵ on line attenuation requirements: in the public broadcasting system, from the output of the amplifier unit to line up of speakers of the line between user attenuation should meet the following requirements:
· Business broadcasting should not exceed 2 DB (1kHz)
· Services of broadcasting should not be greater than 1 DB (1kHz)
⑶ adopts constant pressure output of feed line, the output voltage by 70V or 100V.
⑷ power amplifiers of capacity calculation method:
The business of broadcasting systems and operations of the broadcasting system of calculation method:
P=K1×K2×ΣPo
Type: P--power amplifier output total power (W);
Po--Ki×Pi, each tap at maximum power when broadcasting (W);
Pi--I tap on user devices rated capacity;
Ki--I tap while need coefficient;
Service broadcasting, the rooms show each Ki of 0.2-0.4;
Background music by 0.7-0.8 Ki
K1--line attenuation compensation coefficient: line attenuation while taking 1.26 1dB; line attenuation 2dB from 1.58; when
K2--aging factor, generally take 1.2-1.4;
· Fire broadcasting system of calculation method: the system of calculation method has the following two ways:
A. power amplifier capacity on the system speaker 1.3 times.
B. power amplifier capacity on the system of maximum 3 layer speaker 1.5 times.
⑸ standby power amplifier
Public broadcasting system of the power amplifier should be set back up power amplifiers, power amplifiers in work power amplifier failure can automatically or manually put into use. For important radio power amplifier (such as fire radio power amplifier), its standby power amplifier should be can't work amplifier failure automatically put to use immediately. The number of standby power amplifier should be important to determine the load capacity of broadcasting.
⑹ Speaker settings
· In offices, living rooms, changing rooms, and other Office settings 3W speakers box.
· Floor corridor generally use ceiling loudspeaker, speaker of the spacing by storey (ceiling height) 2.5 times. Choose 3-5W ceiling speakers.
· Hall, conference room, restaurant, retail shopping, entertainment venues and other places to put 3-6W speaker box.
· Room bedside control cabinet 1W-2W speakers.
· In building decoration and room height allows for large space of the use of sound column or combination of speakers.
· Noise is high, the humid place setting speaker, Horn speakers should be used. In places where noise high the Horn speaker sound pressure level than the environment 10-15dB noise.
⑺ broadcasting system power requirements
· Small-capacity radio can supply power directly from the socket; capacity above the 500W, sets the broadcast control room, its power can be used by the nearest power controller-dedicated power supply.
· AC voltage offset value is greater than + General 10%, when the voltage offset does not meet the requirements of the device limitations, you should install the equipment near automatic voltage regulator unit.
· Broadcast AC power supply capacity is generally final broadcasting equipment AC power consumption capacity 1.5-2 times.
· Fire radio equipment using fire power.
⑻ transmission cable choice
· Room service of broadcasting channels use copper conductor multi-core cables or copper conductor stranded wire plastic.
· Other broadcasting channels use copper conductor stranded wire plastic.
· Various programs should use shielded signal cable.
· Fire broadcasting channels should be used for flame retardant copper conductor cable or fire-resistant type copper conductor wireCable.
⑼ line laying
· Lines used to wear steel pipe or cable laying, and lighting, power line and cable laying.
· Fire broadcasting line fire protection measures should be taken.
Emergency broadcast system design:
⑴ fire radio speaker settings should meet the following requirements:
· Emergency broadcast speaker settings in the corridors,halls, restaurants and other public places, the number should be able to guarantee any part from the floor to the most recent one speaker in walking distance of no more than 25 meters. The intersection in the aisle, the corner should set speakers. Sidewalk ends last cry out from the wall is not more than 12 metres. Each speaker rated power should not be less than 3W.
· In-room speakers power should not be less than 1W.
· In-room air conditioning rooms, ventilation, laundry room, recreational facilities and garages are available for background noise such as speakers, plays in its range of playback sound pressure level should be higher than background noise identification 15dB, speaker of power.
⑵ fire broadcasting should not be greater than 100V voltage feeder. Each floor of the feeder isolation voltage regulator to ensure that when any of the tap has a fault, should not affect other tap of a normal radio.
⑶ fire broadcasting output branch should be evacuated sequence control, playback evacuation instructions floor control procedures are as follows:
· N-tier and n-tier or above the floors of a fire, you should connect the fire floor is adjacent to and below.
· First floor there is a fire, you should reach this layer, layer 2 and underground floors.
· Basement there is a fire, you should connect the underground floors and first floor.
⑷ fire broadcasting and service broadcasting or operational radio combination, should meet the following requirements:
· Fire should be able to fire control room will fire evacuation floor speakers and amplifier forced to fire the broadcasting State.
· Fire control rooms should be able to monitor fire radio power amplifier for operation.
· Room bedside cabinet within the speaker, shall have the fire broadcasting function.
· If fire broadcasting and service broadcasting or operational radio and speaker with volume switch, the system should be used in third-line wiring cables forced open the fire so broadcasts.
Public broadcasting is to a limited extent in the public service broadcasting. In General, the public broadcasting signals through housed in broadcasting service area in the broadcast line, is a one-way (download) cable. Usually set in the communities, agencies, services, businesses, schools, buildings, supermarkets and all kinds of venues, for publishing news and information, publication and rest within the signal, provides the background music and paging and been forced into disastrous accident emergency broadcast, etc. Become a modern city and rural areas and in various public places is an integral part. I believe that shocked the world 9.11 event, World Trade Center collapse before its public broadcasting system must process in life-saving play an important role.