Tait TB8100 Service Manual page 57

Connections to the
Reciter
Balanced Audio
Output
Unbalanced Audio
Output
Balanced Audio
Input
Unbalanced Audio
Input
RSSI
Rx Gate
Tx Key
Digital Inputs
TB8100 Service Manual
© Tait Electronics Limited September 2006
The system interface board has two connections to the reciter: a 40-way
flexible connection, and a high-speed connection.
The 40-way connection is essential to the system interface board's operation.
It provides power and communications from the reciter, along with all the
other system interface inputs and outputs.
The high-speed connection is only used on system interface boards which
require a high rate data connection to the reciter processor.
The balanced audio output is a 600Ω audio interface. The output level can
be set over the range –20dBm to +10dBm, for 60% modulation. The
output level can be set with a resolution of 0.1dB. This output may be
either transformer isolated or just AC coupled.
The unbalanced audio output should only be used with high impedance
loads (greater than 10kΩ). The output level can be set over the range
0.3Vpp to 3.0Vpp, for 60% modulation. The output level can be set with
a resolution of 0.1Vpp. This output is AC coupled.
The balanced audio input is a 600Ω audio interface. The input level can be
set over the range –20dBm to +10dBm, for 60% modulation. The input
level can be set with a resolution of 0.1dB. This input may be either
transformer isolated or just AC coupled.
The unbalanced audio input is a high impedance input (greater than 10kΩ).
The input level can be set over the range 0.3Vpp to 3.0Vpp, for 60%
modulation. The input level can be set with a resolution of 0.1Vpp. This
input can be either AC coupled or DC coupled, depending on the type of
board (refer to Table 2.1 on page
The RSSI output is DC coupled and provides a voltage proportional to the
received signal strength with a user-defined characteristic.
The Rx Gate output is an open collector output. The transistor is on when
a valid signal is received. The maximum current rating of this output is
100mA. The maximum voltage that should be applied to this output is 30V.
The Tx Key input has a high input threshold guaranteed to be greater than
5V. The low input threshold is 2V. A low input keys the transmitter.
The digital inputs have 5V logic thresholds and are active low. The
maximum external pull-up voltage on these inputs is 20V.
55).
Reciter Circuit Description 57