Operation Of Control-Head Circuitry - Tait TM8000 Series Service Manual

Operation of Radio
2.3

Operation of Control-head Circuitry

User Interface
Connectors and
Circuit Boards
TM8100 Mobile Radio Service Manual
May 2004 © Tait Electronics Limited
Figure 2.14 is a simplified block diagram of the transceiver architecture
showing the hardware modules integrated with the software modules.
The same DSP (digital signal processor) device includes the software that
controls the transceiver and the software constituting the digital-signal-
processing blocks in Figure
described with reference to
following two parts:
operation in receive mode
operation in transmit mode
Operational descriptions of these two parts are given in
(on page 54) and Subsection 2.5 (on page 57)
In this subsection the operation of the control-head circuitry is
summarised. A detailed description of the circuitry is given in
(on page 63). Control heads with UI provide a user interface consisting
of:
seven-segment LCD
up and down channel-selection keys
four programmable function keys
/
push-button key
ON OFF
LED indicators
volume control
internal speaker
microphone connector
The LCD displays one or two characters depending on the type of
control head. The microphone connector may also be used for the
connection of a handset or programming lead. If required, a concealed
microphone may be fitted inside the control head.
There is an 18-way electrical interface between the control head and
radio body. The physical connection is via an 18-way loom. The control
head normally contains a single PCB assembly called the control-head
board. The differences between the boards for the one- and two-digit-
display control heads are discussed in
dynamic microphone is used or a concealed microphone fitted, a small
circuit board must be mounted on the control-head board. The added
board has the necessary amplification, filtering and switching functions.
The internal speaker is connected to the control-head board via a lead
with a mating connector so that it can be easily disconnected.
2.14. The operation of the radio is then best
Figure 2.14 and with a division into the
respectively.
Section 3 (on page
General Description
Subsection 2.4
Section 3
63). If a
53