Operating instructions

3-12 Amplifier Setup
4
Connect a signal-level meter to the FWD OUT test point and tune the meter to the high
band-edge carrier.
5 Turn the auto level (VADU) potentiometer (illustrated in Figure 2-11) fully clockwise and
then reduce to obtain the level obtained in Step 9 under Manual Gain Control.
VADU/VQADU Pads and Levels
This subsection provides information regarding the proper VADU/VQADU padding
requirements for the MBV3-100*.
A JXP-*B pad is installed in the input line to the VADU/VQADU location. This pad adjusts the
VADU/VQADU input level for the standard application of the MBV3-100* but you can change
this pad depending on the operational output of the MBV3-100*.
In the MBV3-100* analog VADU circuit, a JXP-6B pad is generally recommended. This is the
standard ADU pad value as shipped from the factory and is appropriate for an amplifier output
level range from +43 dBmV to +49 dBmV at 550 MHz. Use a JXP-0B pad for output levels below
+43 dBmV and a JXP-10B for output levels above +49 dBmV.
The standard pad for the VQADU is a JXP-0B. This pad value works for a MBV3-100* output
level from +38 dBmV to +47 dBmV at 550 MHz. Use a JXP-6B when operating above +47 dBmV
at 550 MHz.
Motorola does not recommend operating the MBV3-100* above +46 dBmV at 550 MHz.
Use of a VADU or VQADU is recommended for improved output level stability although you can
operate the MBV3-100* in the manual mode. Select manual mode by placing the drive control
select jumper, illustrated in Figure 2-11, in the
MAN position. The gain of the MBV3-100* is then
determined by the potentiometer marked
MAN on the amplifier cover.
Return Path Alignment
The following subsections describe the MBV3-100* alignment procedures required for proper
performance in the return path.
Before You Begin
Before you begin to set-up the amplifier and perform return-path alignment, please read the
following instructions and recommendations.
For proper return alignment obtain:
 RF alignment levels and insertion points for all MBV3-100*s
 RF reference output level of the headend optical receivers
Equipment required for return-path alignment includes:
 Full complement of JXP-*B pads and STARLINE Return Equalizers (SRE-*-*)
 Reverse signal generator — must produce at least one signal within the return bandpass
and have variable output
 Return sweep or alignment equipment
It is recommended that you:
 Do not remove or install the electronics chassis cover when the MBV3-100* is powered
MBV3-100* Installation and Operation Manual