DB Elettronica Telecomunicazioni CTX 5, User Manual

Page: 10 / 86

DB
ELETTRONICA TELECOMUNICAZIONI S.p.A.
Pag. 10/86
p
SWITCHING ON PROCEDURE
•
Connect an audio generator to the audio inputs of the unit with a 0 dBm signal of test;
•
Connect a video generator on the video input of the unit with a black signal (0% field) as test
signal;
•
Connect a dummy load of at least 50 W on the RF output of the unit in case the CTX is used
as stand alone, or connect a dummy load properly dimensioned at the total output of the
transmitter in case the CTX is a driver unit;
•
Connect the CTX to the mains (220 VAC ± 10%, 50/60 Hz) and switch on it: the output
power level set in the factory is 0 W. Wait up the message STATUS OK appears on the
display;
•
Set the unit to ALC mode (
CONFIGURATIONS MENU -> OUTPUT OPTIONS -> AGC
MODE
);
•
Increase the output power up to the desired level (depending on the fact that the unit is used as
stand alone or as driver for a transmitter) setting the value in the menu
CONFIGURATIONS
MENU -> OUTPUT OPTIONS -> RF OUTPUT (AGC)
;
•
If you have at your disposal a signal demodulator, connect it to the RF MONITOR
connector (of the CTX unit if it works as stand alone otherwise the one of the transmitter)
and adjust the SYNC value up to have the 100% sync in the output of the unit;
•
Adjust the Video level up to have 1Vpp;
•
Adjust the deviation of the unit to optimize the transmission: normally it is factory set
depending on the standard (50 Hz for the PAL and SECAM standards, 25 Hz for the NTSC);
•
Check the voltages on the page
STATUS MENU -> VOLTAGE INFO
and verify that all
the values are correct;
•
The setting of the unit is complete: switch off the unit, disconnect the dummy load from the
output and connect the output to the antenna system. Disconnect the audio and video
generators and connect the signal that will be transmitted on-air. Switch on the unit again and
check that all the parameters are ok and the unit shows the message STATUS OK on the first
page of the menu.
NOTE:
in case the frequency is not at the correct value, it is possible to adjust the value of the 10
MHz external reference using the trimmer on the rear panel up to have the right frequency value.