Tait TB9100 - Page 28

28 Description TB9100/P25 CG/P25 TAG Installation and Operation Manual
© Tait Limited March 2014
12V DC PA-only
subracks
In 12V DC PA-only base stations, the DC power input is connected directly
to the PA, where it is fed to the internal boost regulator board. This board
provides a 12VDC output for the reciter and a 28VDC output for the PA
circuit boards.
Subracks with no PA
and no PMU
When the subrack has neither PMU or PA, reciters or gateway modules
obtain their power from a DC terminal block at the rear of the subrack.
Distribution from
the reciter
The reciter input power feed is distributed to all internal reciter boards.
Local regulation ensures that noise and common mode interface signals are
kept to a minimum between sub-assemblies. Various power supplies in the
reciter further power and isolate critical sub-sections.
The reciter also powers the control panel, via a backpower protection diode.
The system control bus is used to route power from the reciter to the control
panel. When a reciter is powered and plugged into the control bus, if a
control panel is connected there will always be a reciter present to drive the
control bus functions.
Figure 1.6 Subrack power distribution
DC
AC
12V
Aux. DC
28V
28V
28V
Boost
Regulator
28V
12V
12V
Subrack with PMU
12 V DC
PA-only subrack
PMU
PA
PA
Reciter
Reciter
Control
Panel
Control
Panel
10.8 - 32V
10.8
- 32V
Subrack with no
PA and no PMU
Reciter
Control
Panel
DC terminal at
rear of subrack
J17 connector
on subrack inter-
connect board