Return Rf Signal Flow; Before The Return Legs Combine; After The Return Legs Combine - Philips Diamond Line 2 Manual

Return RF Signal Flow

The signal flow is the same
for all three of the Diamond
Line 2 amplifier's return legs.
Refer to Figure 11 as you
read the descriptions in this
section. See also "Accurate
return setup" on page 10 for
a discussion of return-path
features and benefits.
Amplifiers are shipped with
the return output equalizer
and return output attenuator
positions empty; you must
plug both circuits in for the
amplifier to work.
38

Before the Return Legs Combine

Return Input Port (J2, J3, or J4). A return input port routes
incoming return signal to the amplifier. (This port also routes
forward outgoing signal to distribution cables.)
Return Test Signal Injection Point (Output Test Point). Since the
forward output test point allows access to the return band,
you can inject return test signals here (although you can't
measure return signal).
Return Input Diplex Filter. See "Input Diplex Filter" on
page 35.
Return Input Attenuator. A 9-A-WC or 10-A-WC series
plug-in attenuator is used in this position primarily for ingress
isolation. (See page 163.) A "zero" attenuator is shipped in
this slot for circuit continuity.
Return Input Test Point. Accessible through a cut-out in the
module cover, this -20 dB resistive test point lets you verify
the return signals at the return hybrid input. It is
approximately -15dB from the test point's position in the
circuit.
Return Combiner. Return signals from J2, J3, and J4 are
combined into a single feed for the return amplifier. This
three-way combiner has equal (5 dB) loss in each leg.

After the Return Legs Combine

Return Amplifier. This hybrid, which amplifies the combined
return signal, features an improved compression point and bit
error rate (BER) for digital-loaded traffic over a discrete
amplifier design.
Return Output Equalizer. Accessible through a cut-out in the
module cover, the 7-REF-WC series equalizer provides an
output tilt at the return amplifier that will provide a flat input
at the next return amplifier. Amplifiers are shipped with the
return output equalizer position empty. Select and install the
appropriate value based on the amplifier's location in your
network.
A return EDB plug-in may be installed instead of the
7-REF-WC series equalizer to flatten circuitry response
anomalies.
10 July 2000 Diamond Line Amplifiers