Motorola BT100 operation manual Forward Path Alignment, Before You Begin

3-2 Amplifier Setup

Forward Path Alignment

You must perform the following BT100 alignment procedures for proper performance in the forward path:

ƒSelect the appropriate cable equalizer or cable simulator

ƒSelect the appropriate input, midstage, and output pads

ƒVerify proper flatness control

ƒVerify 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:

ƒRF output levels and tilts of all BT100s in the forward or return path

ƒRF input level for the BT100 being set up (from system design or as-built map)

ƒA 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:

ƒInstall 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.

ƒDo not remove or install the electronics chassis cover while the BT100 is powered.

ƒIf 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.

ƒDo not use wire jumpers to bypass the SFE-100-* location.

ƒRecognize 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.

ƒSecure the electronics chassis in the housing and torque to 18 to 22 in-lbs. to facilitate heat transfer and avoid damage from overheating.

ƒPerform a bench alignment. Pre-aligning the BT100 response on the bench (Section 4, “Bench Testing”) for a system signature simplifies field alignment.

ƒField sweep the entire bandwidth of the amplifier to correct frequency response for passive signature and roll-off.

ƒClose the housing in accordance with the instructions in Section 5, “Installation.”

BT100 Installation and Operation Manual