ADC Telecommunications Inc. DVICSRIU800 Benutzerhandbuch
ADCP-75-114 • Issue C • June 2001
Page 3
©
2001, ADC Telecommunications, Inc.
1.3 Fault Detection and Alarm Reporting
The
RIU is designed to detect a power amplifier over or under current condition and a high
temperature
condition. A single front panel Light Emitting Diode (LED) indicator turns from
green
to red or yellow if a fault is detected. A set of alarm contacts (normally open and
normally
closed) are also provided for reporting an alarm to an external alarm system when a
fault
is detected. Both major alarm (power amplifier over/undercurrent condition or power
failure)
and minor alarm (high temperature) contacts are provided.
1.4 RF Signal Connections
The
RF signal connections between the RIU and DHU are supported through a pair of type N
female
connectors mounted on the RIU front panel. One connector is used for connecting the
forward
path coaxial cable and the other connector is used for connecting the reverse path coaxial
cable.
The RF signal connection between the RIU and the donor antenna is supported through a
single
type N female connector. The single connector is used for connecting the coaxial jumper
cable
that links the RIU to the donor antenna. The DHU cannot be connected directly to a donor
antenna
and requires an interface device such as the RIU.
Note: To comply with Maximum Permissible Exposure (MPE) requirements, antennas must be
installed
to provide at least 20 centimeters (8 inches) of separation from all persons per FCC
47
CFR part 2.1091.
1.5 RF Signal Level Adjustments
The
RIU is equipped with two digital 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. In the forward path, this range provides a maximum
gain
of +40 dB (with attenuator set to 0) or a minimum gain of +9 dB (with attenuator set to 31
dB).
In the reverse path, this range provides a maximum gain of +59 dB (with attenuator set
to
0) or a minimum gain of +28 dB (with attenuator set to 31 dB). Each attenuator is adjustable
by
means of two rotary switches which are mounted behind the RIU front panel. Access to
each
rotary switch is through a small hole. A small screwdriver is required to adjust the switch
setting.
Turning each switch adds or removes attenuation and therefore adjusts the signal level
of
the specified signal path.
1.6 Powering
The
RIU is powered by 120/240 VAC (50–60 Hz) power which is supplied through a standard
three-conductor
AC power cord. The power cord is provided with the RIU and is 98 inches
(2.5
meters ) long. A resetable circuit breaker/On-Off switch is provided at the unit front panel.
The
switch applies power to the RIU internal power supply.
1.7 Cooling
Continuous
air flow for cooling is provided by a fan mounted on the right side of the housing.
A
minimum of 3 inches (76 mm) of clearance space must be provided on both the left and right
sides
of the RIU for air intake and exhaust. An alarm is provided that indicates if a high
temperature
condition (>58º C/136º F) occurs. The fan may be field-replaced if it fails.