Motorola BLE*/* - Manual (Page 19)

2-8 Overview
BLE*/* Installation and Operation Manual
The input and output of the return path each include a JXP-*B pad facility. You can also use
either pad socket as a test point or a signal injection point. The return output pad value is
normally selected to control the return signal level into the next upstream amplifier. Select an
appropriate return input pad to attenuate excessive input signal.
The return-input test point and the return-output test point are
−20 dB directional couplers.
Both test points present 75-ohm source impedance and do not require special test probes.
Ingress Control Switch
The ingress control switch (ICS) provides return-path signal attenuation or cutoff in the BLE*/*.
This is accomplished through the frequency agile LIFELINE
® status-monitoring module,
LL-BLE-HMS-*/*. (Figure 2-8 illustrates the location of the optional ICS).
The ICS provides a means of isolating sources of ingress from a centralized location. Using a
downstream command through the LIFELINE status-monitoring system, you can attenuate the
return path through the line extender by 6 dB or by 38 dB. By reducing the ingress level at the
headend or monitoring point, you can further isolate the ingress source.
After an ingress source is isolated to the last possible amplifier, node, or line extender, you can
shut the return path off at that location. This limits the impact of the ingress on the remainder
of the network while eliminating the source of ingress.
Options and Accessories
The factory ships the BLE*/* as a fully functional unit, but you must configure it appropriately
for the field-location requirements. You must install the correct forward equalizer or broadband
cable simulator and input pad to place the unit into service. Section 3, “Amplifier Setup”
provides information to assist you in this task. Use model JXP-*B pads to control field signal
levels. To compensate for temperature, install the automatic drive unit (ADU) or thermal drive
unit (TDU) before placing the BLE*/* in service. You can install other items, such as a return
amplifier and additional surge protection (model FTEC-BTA) at your discretion, but these
options do not render the BLE*/* inoperative if they are not included.
Table 2-1 provides a comprehensive list of options and accessories for the BLE*/*:
Table 2-1
BLE*/* options and accessories
Model Description Function
ADU-* Automatic Drive Unit This board automatically controls amplifier output levels
that change with cable attenuation and hybrid output.
The selection of a pilot frequency is required.
TDU Thermal Drive Unit This board controls amplifier gain and slope for
changes in cable attenuation for the sensed
temperature.
RA-Kit/H or L Return Amplifier Kit This kit enables two-way operation and includes a
high-or low-gain return hybrid and jumpers.
SFE-0, SFE-1 Starline Forward Equalizers These equalizers are not bandwidth specific and
compensate for 0 dB and 1 dB of cable, respectively,
from 5 MHz to 1 GHz.