Measuring forward gain, Example – Motorola BT100 User Manual
Page 41
4-2
Bench Testing
BT100 Installation and Operation Manual
CAUTION!
To protect the network analyzer, you must configure the SSP-PIN power combiner to block AC power from the input
port.
To preserve signal quality, verify that all unused ports are terminated.
CAUTION!
Before you begin the following subsection, remove the input pad (JXP IN) before you apply power. This is necessary
to avoid damage to the hybrids.
Measuring Forward Gain
This subsection provides instructions for measuring the full gain and the operational gain and
flatness of the BT100.
To measure the full gain of the amplifier:
1
Determine whether the power-supply jumper is positioned for 60 V or 90 V operation.
2
Connect the BT100 to the test equipment as illustrated in Figure 4-1 and apply power.
3
Verify that the DC voltage is 24 V
± 0.4 V and re-install the input pad.
4
Apply the sweep signal and adjust test equipment as needed.
5
Select manual gain by placing the drive control select jumper in the
MAN
position and turn
the
MANUAL LEVEL
control (
MAN
) (Figure 2-13) fully clockwise.
6
Measure the gain at mixed forward frequency using the procedure outlined in the operator
manual provided with the test equipment in use.
To correct this number, add the insertion loss of the SSP-PIN power combiner (0.6 dB at
750 MHz, 0.7 dB at 870 MHz, or 1.1 dB at 1 GHz), the loss of the cable simulator at mixed
forward frequency, and the loss of the cable equalizer (1.0 dB), if it is installed.
Example
The test equipment indicates a measured gain of 24 dB with a BT100 and the cable
simulator is set to 20 dB.
1.1 dB (power combiner)
+ 1.0 dB (cable equalizer)
+ 20.0 dB (cable simulator)
+ 24.0 dB (measured gain).
46.1 dB (unit gain).
The result must meet advertised specifications for the unit.
The operational gain of the BT100 provides reduced gain capability. This enables the unit to
operate in the proper region of the Bode board when it is controlled by the ADU or QADU drive
units.
To measure the operational gain and flatness of the amplifier: