4RF Aprisa XE User Manual page 110

108 | Configuring the Traffic Interfaces
Line Termination Impedance
The line termination impedance (Zt) is the impedance seen looking into the DFXO or DFXS interface. The
line termination impedance is not the same as the hybrid balance impedance network (Zb) but can be set
to the same value.
Changing the DFXO / DFXS impedance setting on the Aprisa XE changes both the line termination
impedance and the hybrid balance impedance to the same value.
Hybrid Balance Impedance
The hybrid balance impedance (Zb) is the impedance network on the opposite side of the hybrid from the
DFXO / DFXS line interface. The purpose of this network is to balance the hybrid to the impedance
presented to the DFXO / DFXS line interface.
Changing the DFXO / DFXS impedance setting on the Aprisa XE changes both the line termination
impedance and the hybrid balance impedance to the same value.
Transhybrid loss
Transhybrid loss is a measure of how much analogue signal received from the remote terminal is passed
across the hybrid and sent to the remote terminal.
The transhybrid loss is maximized when the hybrid balance impedance matches the impedance presented
to the DFXO / DFXS line interface. An optimized hybrid minimizes circuit echo.
Aprisa XE User Manual