Motorola BT100 - Manual (Page 38)

Amplifier Setup 3-13
BT100 Installation and Operation Manual
ƒ Reverse signal generator — must produce at least one signal within the return bandpass
and have variable output
ƒ Return sweep or alignment equipment
It is recommended that you:
ƒ Do not remove or install the electronics chassis cover when the BT100 is powered
ƒ Do not use wire jumpers to bypass the SRE-100-* location
ƒ Perform the return optical link set up before performing amplifier set up
ƒ Specify reverse alignment design levels for a single carrier
ƒ Consider sweep equipment as a single carrier and operate at design levels
ƒ Do not include injection point losses in reverse design levels
If JXP THERM devices (JXP-TH*C) are specified for level control, they should be installed in
the JXP THERM pad facility (illustrated in Figure 2-13) prior to alignment.
Alignment Procedure
The return amplifier configuration includes one high-gain (30 dB) return amplifier hybrid, and
an appropriate SRE-100-* equalizer. All components are plug-in and are easily installed.
To align the return path:
1 If the BT100 is powered, remove all fuses before you perform the following steps.
2 Install the design value pad in the return output pad location (JXP) which is located directly
beneath the JXP THERM.
3 Install the design value return equalizer, SRE-100-*, in the location “RTN EQ”.
4 Verify that the return input pad locations (JXP, JXP 1, JXP 3, and JXP 4) have 0 dB pads
(or JXP-ZX jumpers) installed.
5 If you require ICSs, install them in the ICS locations illustrated in Figure 2-13. If you plan
to install the ICSs later, install JXP-2Bs to simulate the through-loss of the ICSs. This
eliminates the need to rebalance the return path if you install the ICS later.
6 Verify that the return pad (JXP location located to the right of the return hybrid) has a 0 dB
pad (or JXP-ZX jumper) installed.
7 Verify that the return thermal pad socket (JXP THERM), located between the hybrid output
and the SRE-100-*, has a 0 dB pad (or JXP-ZX jumper) or a JXP-TH*C installed.
8 Set the sweep equipment output level to the amplifier’s design input level. Add insertion
point loss.
9 If required, change the return output pad and/or equalizer to achieve, as close as possible, a
match of the reference level as compared to the node.
10 Verify the sweep response of all insertion points, if applicable.
11 Verify that the pad and equalizer values are similar to the map design values.
For systems that must meet especially stringent return-path flatness requirements, you may need
additional flatness response correction in the return path. You can obtain additional flatness by
installing the JXP-RPC board in one of the return-path JXP pad facilities. The recommended
location is the JXP-THERM pad facility. However, if you are using JXP-THERMS in the return