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TB9400/TN9275 Installation and Operation
Description
33
© Tait International Limited
May 2023
1.8.1
Signal Paths
gives an overview of signal paths within the reciter.
Digital P25 signals from the receive RF interface pass through the digital
receiver and P25 modem to the control firmware in the control processor.
The control firmware passes the signal through the Ethernet interface to the
site controller (P25 trunked networks), to the console gateway
(conventional networks), or for a satellite, to the central voter in a simulcast
system.
Input to the Ethernet interface can be from the site controller (P25 trunked
networks), from the console gateway (conventional networks), or from the
central voter in a simulcast system. These inputs are processed by the
control processor and passed through the P25 modem to the transmitter. If
the base station is itself a central voter, this input can also be a received
signal, which is voted on and sent back through the Ethernet interface to the
site controller.
1.8.2
Online and Offline Modes
The base station normally operates in Online mode, but Offline mode can
be selected via its WebUI.
Online Mode
In Online mode, the base station is in service and performs its normal
functions of transmitting and receiving radio signals.
Figure 1.6
Reciter signal paths
Modulator
Demodulator
P25
Modem
FM
Baseband
Audio
G.711
Control
ADC
DDC
DAC
RTP
UDP
IP
Transmit
RF Interface
Receive
RF Interface
Ethernet
Interface
Protocol
Stack
Reciter Control Board
Cartesian
Loop
ADC
Transmit
RF Interface
(feedback
from PA)