1 Public address (PA)
Sound broadcast that is managed by the user and serves the public within the area occupied by the user. It includes business
announcement, background broadcast, and emergency broadcast.
2 Public address system
A system composed of all public address equipments and facilities serving public address coverage area, as well as the acoustic
environment of this public address coverage area.
3 Public address equipment
A general term for all the equipments in public address system. It includes loudspeakers, power amplifiers, transmission lines
and transmission equipments, management/control equipments, paging equipments, microphones and other signal source
4 Emergency broadcast
Broadcast by public address system to its service zone(s) in case of public emergency. For example, alarm signals, guidance
information about public evacuation, and instructions given by relevant departments on the emergency site.
5 Business announcement
An announcement releasedby public address system to its service zone(s) intended for the whole or part of the audience. For
example, notices, news, information, voice files, paging, time tones, etc.
6 Background broadcast
Broadcast by public address system to its service zone(s) to create a certain atmosphere. For example, background music and
background sounds (including environmental simulation sounds) in a variety of occasions, etc.
7 Loudspeakers distribution
To design and allocate loudspeakers in specific area of public address system.
8 Transmission line
Lines that used for transmitting public address signals from signal processing equipment(s) (including amplifiers) or station to
onsite loudspeakers in the service zone(s), including various conductive cables and optic-fiber networks.
9 Transmission distance
Length of the line from the input terminal of public address Transmission line to the load terminal.
10 Rated transmission voltage
Rated voltage of the original terminal of Transmission line. That is, the nominal input voltage of loudspeaker (or some other
terminal devices) connected to the Transmission line.
11 Ensured function
The most basic function that public address system shall provide.
The priority of source signals to be broadcast.
13 Microphone priority
To enable a microphone the highest airing priority.
14 Voice file
The broadcast voice recorded in advance.
15 Dual function system
The standby mode of emergency broadcast system. Normally, the system runs as a business announcement system or
background broadcast system. When triggered by an emergency signal, the system switches automatically to emergency
16 One touch ready
Makepublic address systemto enter a specified state by one touch.
Broadcast intended for seeking person, things or help, or temporary broadcast to the designated zone(s) as required.
18 Call station
The device that is independent from the broadcast host and can make zone Paging.
To Override other signals being on-air with specific contents, or to forcibly awaken the stand-by system in order to release
20 Zone management
To divide public address service area into several broadcast zones and manage them. Broadcasting can be turned on or off
for each zone separately or for all zones.
21 Zoning with matrix mode
To mange broadcast zones in matrix mode. Broadcasting can be turned on or off separately for each zone, and different
signals can be sent to two or more zones simultaneously.
22 Zoning override
To Override one or more broadcast zones selectively without affecting other zones.
23 Remote control and monitor
To monitor and control public address system outside the station (or control center).
24 Ensured sound pressure level
The averaged value of the root-mean-squared (RMS) steady-state sound pressure level that shall be achieved in public
25 Sound field irregularity
The maximum difference between Sound Pressure Level (SPL) values measured in public address zone.
26 Leak out acoustic attenuation
The difference between the Ensured sound pressure level of public address system and the SPL30moutside the border of the
27 System signal-to-noise ratio
The signal-to-noise ratio from the audio signal input terminal of public address system