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Directional coupler test points, Bode equalization – Motorola BLE*/* User Manual

Page 29

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3-8

Amplifier Setup

BLE*/* Installation and Operation Manual

Figure 3-4 illustrates BLE87* flatness and control ranges:

Figure 3-4
Typical flatness and control ranges

CH2 S21 /M log MAG

BLE87S/12/G

1 dB/ REF 30.49 dB

4: 30.757 dB

870.000 000 MHz

1: 30.434 dB

52 MHz

2: 30.306 dB

200 MHz

3: 30.394 dB

800 MHz

4

3

2

10:22:15

25 Jun 2001

1

PRm

C?

Del

14.7 dB P3-412 @870.0 MHz

START 52.000 000 MHz

STOP 900.000 000 MHz

Directional Coupler Test Points

Accurate

−20 dB directional-coupler test points are available at the input and at the output of

the BLE*/*. Because these test points are 75-ohm source impedance, they do not require special
test probes.

After the output hybrid, a second directional coupler provides signal to the optional ADU board.
This signal is used only when the ADU board is installed. It is not necessary to terminate this
port when the ADU is not installed.

Bode Equalization

The Bode board, which is an electronically controlled equalizer, receives its control input from
either the ADU or TDU control boards. The response of the Bode board compensates for cable
attenuation changes due to temperature. If necessary, you can control the Bode board manually
using the potentiometer labeled Manual Level (

MAN

) in Figure 2-8.