User's Manual

4-12 888-2687-001 10/19/07
WARNING: Disconnect primary power prior to servicing.
Ranger ™ Mobile Series
Section 4 Theory of Operation
4.4 Transmitter RF System
Figure 4-4 shows a simplified block diagram of the transmitter RF system. The RF
system for each model will be described separately.
4.4.1 CZ500F RF System Description
The CZ500F has only one PA module, which makes the RF system very simple. The
Apex
R
exciter feeds the Splitter board. The RF drive output of the splitter going to PA2
is simply terminated with a 50 ohm load. The PA Module output is determined by the
exciter power level. The PA module output passes through the circulator to the mask
filter and then to the cabinet RF output. The circulator reject load is a 1kW 40dB
attenuator which supplies a sample of the reflected power to the RF Monitor Board for
metering on the GUI Output Service screen.
There are Forward and Reflected power directional coupler samples both before and
after the mask filter for calibration and metering. A third sample is provided after the
mask filter for the RTAC (Real Time Adaptive Correction) sample required by the
Apex
R
exciter.
The Backplane Interface board provides for connection of the Control bus (CAN bus
and parallel control lines) and the LVPS (+/-15Vdc and +7.5Vdc) for the module.
Figure 4-3 CZ500F RF System Block Diagram
RF Monitor Board
*Mask
Filter
A - PA Forward
B - PA Reflected
C - Total Forward
D - Total Reflected
A
B
RTAC
PA 1
Backplane
Interface
RF Drive
Fixed
CD-1A
Exciter
RF Drive
Reject
Load
Splitter
Control Bus
and LVPS
To PA 1
C
1kW 40dB
Attenuator
C D
50 ohm
Load
*CZ500F mask filter is located outside the transmitter cabinet.
Circulator