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RF Technology R50
6 Field Alignment (Calibr ation) Pr ocedur e
6.1 Standar d Test Equipment
Some, or all of the following equipment will be required:
•
Power supply set to 28Vdc, with current >0.25A.
•
RF Signal Generator with 50 Ohm Output impedance, and Frequency range
25-50MHz. The signal generator must be capable of generating a carrier aith
output level adjustable from –60dBm to –128dBm. It must be able to FM
modulate the carrier with a 1kHz audio signal with deviations of 3 and 5kHz.
•
Frequency Counter, or spectrum analyser, capable of measuring frequency
accurate to 0.5ppm.
•
True RMS AC voltmeter with bandwidth > 20kHz, and,
•
a DC voltmeter.
6.2 Invoking the Calibr ation Pr ocedur e Manually
From Version 4 of the firmware, and version 1.4 of WinTekHelp, the calibration
procedure can be performed through a Windows front end program. This is
documented in the WinTekHelp manual. It is recommended that you use the
new Windows based procedure for calibrating each R50.
The firmware still supports the older command prompt method, which is described in
this section.
The firmware will requests the user for information as to meter readings, and/or to
attach or adjust an AF signal generator.
The firmware based calibration program can be accessed from a terminal, a terminal
emulator, or the WinTekHelp terminal emulator.
If the user selects the “Go to the Prompt Window” option from the main menu, they
can manually type commands to invoke the calibration procedure. When the
exciter is ready to accept commands it echoes the following prompt:
R50>
Via a terminal, or a terminal emulator, a user can type various commands in. The
basic command to start the calibration procedure is:
R50>
cal calibration_type
Where "calibration_type" is one of:
(a) misc: Miscellaneous parameters are defined and calibrated
(b) line:
Line1, Line2, Dir Aud (Tone), and microphone inputs are
tested and calibrated.
(c) ref:The reference oscillators are adjusted and calibrated
6.3 The " Miscellaneous" Calibr ation Pr ocedur e
R50>
cal misc
This procedure should not normally be invoked as part of any field maintenance.
The program will print out the Model Name and Serial Number of the exciter. If these
parameters haven't already been defined (e.g. at an initial calibration, at the
factory, the service personnel will be prompted to enter these values).
