Motorola SG 2000 用户手册
O p e r a t i o n
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SG 20 00 Ins tal la tion and O pera tion M anua l
In g re ss Con trol
The SG 2000 platform incorporates electronic ingress control switching enabling operators to choose
one of three options for troubleshooting noise sources. A maximum of four switches, (one ingress
switch per RF port) can populate the RF amplifier. Figure 3-2 illustrates their location on the RF
chassis.
one of three options for troubleshooting noise sources. A maximum of four switches, (one ingress
switch per RF port) can populate the RF amplifier. Figure 3-2 illustrates their location on the RF
chassis.
Ingress switches are controlled in one of two ways: (1) remotely — through the optional on-board
LL-SG2 transponder in communication with the status monitoring system or; (2) locally — using the
manual control board (MCB).
LL-SG2 transponder in communication with the status monitoring system or; (2) locally — using the
manual control board (MCB).
The three states of the switch and their functions include:
State Desc ription
Off
Effectively isolates the contaminated leg by adding a minimum of 40 dB attenuation.
–6 dB
Typically initiated at the headend, it provides –6 dB additional attenuation to the return
signal. This is useful in diagnosing noise presence without interfering with normal
service.
signal. This is useful in diagnosing noise presence without interfering with normal
service.
On
Completes the return path without alteration to the return signal.