Tait TB9100, Installation And Operation Manual

Page: 118 / 144

118 Technical Description TB9100 Installation and Operation Manual
© Tait Electronics Limited May 2006
8.5 Control Panel
The control panel is designed to be the link between the user and the
TB9100 base station. The circuitry for the operation of the control panel is
located on a board mounted behind its front face. All communication
between the base station and the control panel is via the system control bus.
Figure 8.15 shows the configuration of the main circuit blocks, and the main
inputs and outputs for power, audio and control signals.
Control Circuitry
The control panel board translates:
■
I
2
C messages from the reciter into an appropriate response on the LEDs
■
control panel key inputs and fan rotation inputs from both fans into
appropriate I
2
C messages.
Audio Circuitry
The control panel provides a volume knob to control the volume of the
speaker. In addition, the control panel circuitry performs gain control so that
the power output into a 16
Ω
speaker is
≥
0.5W at the maximum position of
the knob, with an input of 167 mV pp.
Power Supply
The control panel operates off a 28 V (nominal) power supply provided by
the reciter. The power supply for the cooling fans mounted on the front
panel is fed through the control panel.
Figure 8.15 Control panel high-level diagram
I C
Translation
2
Microphone
Pre-emphasis
& Gain Control
Speaker
Volume &
Gain Control
LEDs &
Switches
Control
Panel
Microphone
Connector
Speaker
Fan Inputs
Power
Supply
Microphone Audio
System
Control Bus
Speaker
Enable
Speaker Audio
I C Bus
2
28V, GND
Fan Power & GND