Operations Manual

Page 18 RF Technology R50
6 FIELD ALIGNMENT (CALIBRATION) PROCEDURE
D911 is a 4.096V (3%) reference diode. Its output is buffered by U906 which then
produces a reference voltage rail Vref, which is used by the CPU's A/D converter, and
the DACs.
6 Field Alignment (Calibration) Procedure
6.1 Standard Test Equipment
Some, or all of the following equipment will be required:
Power supply set to 28Vdc, with current >1A.
RF Signal Generator
50 Ohm Output impedance
Frequency range 25-50MHz
FM modulation at 1KHz
3KHz peak deviation for 25KHz or 20KHz channel spacing
Frequency Counter
The accuracy should be at least 0.5ppm, preferably 0.1ppm
True RMS AC voltmeter, and a DC voltmeter.
6.2 Invoking the Calibration Procedure
The R50 has in-built firmware to perform calibration. This firmware requests the user
for information as to meter readings, and/or to attach or adjust the AF signal generator.
The firmware based calibration program can be accessed from a terminal, a terminal
emulator, or the Eclipse50 terminal emulator.
As for Section 4.1, the firmware, after power up, issues 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
(d) all : (which does all the above)