User's Manual

ADCP-75-187 • Issue 1 • September 2005 • Section 2: DESCRIPTION

Page 2-4

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.

2.8 Controller Area Network Interface Connection

Controller Area Network (CAN) interface connections between multiple HUs are supported by

a pair of RJ-45 jacks. One of the jacks is designated as the network IN port and the other jack is

designated as the network OUT port. The CAN interface allows up to 24 HUs to be connected

together (in daisy-chain fashion) and controlled through a single EMS computer.

2.9 Service Interface Connection

The service interface connection between the HU and the EMS computer is supported by a

single DB-9 female connector. The service connector provides an RS-232 DTE interface. When

multiple HUs are networked together, the supporting EMS computer may be connected to the

service connector of any one of the networked HUs.

Note: The optimum composite RF input signal level is –20 dBm.