User's Manual Part 1

ADCP-75-187 • Preliminary Issue 1B • November 2005 • Section 2: DESCRIPTION
Page 2-4
© 2005, ADC Telecommunications, Inc.
2.4 RF Signal Connections
The RF signal connections between the rear access HU and the EBTS are supported through
four N-type female connectors. Two connectors are used for the forward path RF signals and
two connectors are used for the reverse path RF signals.
The RF signal connections between the front access HU and the EBTS are supported through
two N-type female connectors. One connector is used for the forward path RF signal and the
other connector is used for the reverse path RF signal.
In most installations, it is usually necessary to install external attenuators to support the RF
interface between the HU and the EBTS. The HU should be as close as possible to the EBTS to
minimize coaxial cable losses.
2.5 RF Signal Level Adjustments
The HU is equipped with several attenuators for adjusting the signal levels of the forward and
reverse path RF signals. The attenuators provide an attenuation adjustment range of 0 to 31 dB
and can be set in 1 dB increments. The attenuators are software controlled and are adjusted
through the EMS software GUI, NOC/NEM interface, or SNMP interface.
The host forward path attenuators adjust the level of the input RF signal(s) to the HU. Using
the forward path attenuator, an input signal with a nominal composite signal level of –9 dBm to
–40 dBm can be adjusted to produce maximum power output. Additional external attenuation
is required if the input signal level is greater than –9 dBm.
The host reverse path attenuators adjust the level of the output RF signal(s) from the HU and
will add from –1 dB of gain (attenuator set to 31 dB) to +30 dB of gain (attenuator set to 0 dB)
to the RF output signal(s) at the HU.
2.6 Propagation Delay
The HU forward and reverse path propagation delays may be adjusted in 0.1 µsec increments
within a range of 0 to 63 µs. The propagation delay is software controlled and may be adjusted
through the EMS software GUI, NOC/NEM interface, or SNMP interface.
2.7 Optical Connection
Optical connections between the HU and the RU are supported through two optical ports
equipped with UPC/SC (flat) connectors. One port is used for the forward path optical signal
connection and the other port is used for the reverse path optical signal connection.
Note: The optimum composite RF input signal level for 800/900 MHz SMR systems is
–20 dBm.