Motorola BT100 - Manual (Page 27)

3-2 Amplifier Setup
BT100 Installation and Operation Manual
Forward Path Alignment
You must perform the following BT100 alignment procedures for proper performance in the
forward path:
ƒ Select the appropriate cable equalizer or cable simulator
ƒ Select the appropriate input, midstage, and output pads
ƒ Verify proper flatness control
ƒ Verify proper level control
Before You Begin
Before you begin to set-up the amplifier and perform forward-path alignment, please read the
following instructions and recommendations.
For proper forward alignment obtain:
ƒ RF output levels and tilts of all BT100s in the forward or return path
ƒ RF input level for the BT100 being set up (from system design or as-built map)
ƒ A carrier at the system’s highest frequency. It can be modulated or continuous wave (CW)
and should be inserted in the headend at standard video levels. This carrier is used to
simplify field set-up.
It is recommended that you:
ƒ Install the system design value SFE-100-* and a high value (20 dB or above) forward input
pad (JXP IN) before you install or remove the electronics chassis or apply power to the
BT100.
Leave the forward input pad location open if a high value pad is not available. A more
accurate forward input test point reading is achieved with a high value pad installed.
ƒ Do not remove or install the electronics chassis cover while the BT100 is powered.
ƒ If you need to remove or install the electronics chassis cover for any reason, shut off
the AC power first. Verify that all chassis cover screws are tightened to 10–12 in-lbs.
ƒ Do not use wire jumpers to bypass the SFE-100-* location.
ƒ Recognize that actual pad and SFE-100-* values may differ slightly from their design
values. This is caused by factors such as walkout errors, worst-case data utilization during
design and temperature variation from 70
°F.
ƒ Secure the electronics chassis in the housing and torque to 18 to 22 in-lbs. to facilitate heat
transfer and avoid damage from overheating.
ƒ Perform a bench alignment. Pre-aligning the BT100 response on the bench (Section 4,
“Bench Testing”) for a system signature simplifies field alignment.
ƒ Field sweep the entire bandwidth of the amplifier to correct frequency response for passive
signature and roll-off.
ƒ Close the housing in accordance with the instructions in Section 5, “Installation.”