The "Line" Calibration Procedure - RF Technology Eclipse Series Operation And Maintenance Manual

6 FIELD ALIGNMENT PROCEDURE
This procedure is similar to the maximum deviation procedure (See 6.5). The Line 1
and Line 2 audio paths are turned off for this procedure, as is the Direct Audio (TONE)
input. The only signal sent to the modulator is a tone of 107.2Hz.
The program starts off, with the following message:
This procedure sets the maximum tone deviations for a
Max Deviation of 5kHz. Note that the actual maximum
tone deviations automatically scale with the Max Deviation.
eg a 500Hz tone deviation would be a 250Hz tone deviation
when a 2.5kHz Max Deviation was chosen.
Disconnect the RF connection to the PA,
and connect a deviation meter to the exciter's BNC output.
The audio is being switched off, and 107.2Hz tone generated
Enter the User Specified Tone Deviation(Hz):
The user is expected to connect up the deviation meter, and enter the User Specified
Maximum Tone Deviation. This is a deviation that is different to the standard
deviations of 750Hz, 500Hz, 375Hz, 250Hz, and 150Hz. The factory default for this is
600Hz.
Thence a procedure that is almost identical to that used for setting maximum deviations
is used to set these tone deviations. There is one significant difference, though, and that
is, as well as using + (or p, or P), and – (or m, or M) keys to step the deviation up or
down, one can also use the < key, or the > key. These last two keys will step down, or
up, the level of signal transmitted by U500, whereas the other keys will modify the
setting of the digital POT U503 (see 5.5).
6.7

The "Line" Calibration Procedure

T50> cal line
This procedure should not be used as part of any usual field maintenance, unless any
component has been replaced that might affect the gain of any of the audio inputs.
Note that if the deviations are calibrated, then this procedure will be automatically
invoked.
The program begins:
Calibrating Line 1 and Line 2 audio levels
Attach an audio signal generator to Line 1
Set the output to be a sine wave, 388mV rms and 1kHz
Disconnect the RF connection to the PA
and connect a deviation meter to the exciter's BNC output.
Enter + or - to increase or decrease the deviation,
and <RET> when the deviation is 3kHz
RF Technology T50 Page 33