TB7100 Service Manual Functional Description 31
© Tait Electronics Limited October 2005
UI Board
The UI board does not include a microprocessor. A synchronous bi-
directional serial interface provides communication of key status, LCD and
LED-indicator data between the transmitter/receiver boards and the UI
board. The serial data is converted to or from a parallel form by a number
of shift registers for the function keys and indicators. For the LCD, the serial
data is fed to a driver IC that converts the serial data to a form suitable for
the LCD. The keys are scanned and the LCD and LED indicators updated
approximately every 50ms. The T
X/RX switch controls what is displayed on
the LCD and also whether the transmitter board or the receiver board will
be programmed.
Programming
Application
The programming application is a program on a PC that is connected to the
base station via the P
ROG/MIC connector on the user interface.
The programming application enables the user to program the base station
with the required channels and subaudible signalling settings.
The transmitter and receiver modules are programmed individually
according to the setting of the T
X/RX switch on the front panel.
Calibration
Application
The calibration application is a program on a PC that is connected to the
base station via the P
ROG/MIC connector on the user interface.
The transmitter and receiver modules are designed to be totally
electronically tuned. No physical tuning is required, as all tuning is done by
electronic trimming. The calibration application can assist in the tuning of:
■ AD6521 CODEC voltage reference
■ TCXO frequency
■ receiver front end
■ transmitter driver and final gate bias limit
■ transmitter power control
■ deviation and squelch.
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