* Public Address System Intelligent Public Address System
13
III. Typical system
3
—
1
Structure of typical system
See figure 3-1 for the structure of a typical system
3
—
2
Connection of typical system
Arrangement of prior input port: prior microphone and chime/alarm signals are still connected to prior input
module like the minimum system, to develop its prior function.
Arrangement of normal input port: only a on-duty microphone is arranged for the person on duty to publish
notices or give calls. The microphone occupies the normal input port, and partition operation is available, not
all background music will be mute. Notes: although the emergency microphone on the front panel can be
used by the person on duty, it has the privilege of first class priority (only next to the “full alarm” manual
button of the absolute priority), so conflicts may occur between it and alarms and other break-in broadcasts,
thus it should not be used randomly and should be used at need.
A normal input port
is distributed to
DSPPA
special sound source and
CD
each, so that they will not restrict
each other, and at the same time, provide different background music for different broadcasting partitions.
Other normal input ports can be used by any external sound sources. For example, to provide several leisure
programs to guest rooms (if any) in the broadcast service area, several CD players or tuners can be connected
externally. Additionally, arrange a meeting room as a speaker partition, and distribute a standby input port to
it (pre-embed lines in the field). When necessary, externally connect the sound console and provide several
microphones, to be used for conference call. And if arrange a square as a speaker partition, and set a standby
input port at a corner of the square. When necessary, externally connect the sound console and provide
several microphones, to be used for public address of a temporary square meeting.
Speaker partitions with a volume controller should better use a three-wire system broadcasting amplifier. By
using this, plenty of pipelines can be saved. Especially important partitions should better use primary/standby
amamplifier automatic switchover, to ensure a reliable system.
Figure 3-1 Block diagram of typical system
Broadcast
ing
amplifier
Area
1
Remote
partition call
Connect to city
call line
Connect to fire
control center
m
n
MIC
×
m
LINE
×
n
Broadcas
ting
amplifie
r
Power time
sequencer
Supply power to
broadcasting
amplifier and
other devices
Monitor voice box
Remote
partition
call
Area n
Smart broadcasting system
Prior
microphone
