Barco PULSAR BG, User Manual

Page: 57 / 126

P
ULSAR
BG Main Scr/Aux Unscr
Page 1
1 DESCRIPTION
A P
ULSAR
equipped with this option is able to work with specified (see warning) scrambled video on
the main (scrambled) input. An unscrambled signal will be placed on the aux input. If the detector
does not find any signal at the main input, the P
ULSAR
will switch automatically -after a short select-
able delay- to the unscrambled signal at the aux input. The audio signal will be switched also. It is
also remotely controllable by means of a hard contact at the rear panel or by the RS-485 connector.
There are some conditions that must be fulfilled before this main scrambled/aux unscrambled option
can be used:
•
The scrambled signal must be well clamped in the scrambler itself: no DC-level variation in time
or temperature. However, if there would be a constant DC-shift in the video, it can be compen-
sated by setting the DC-offset.
•
Hum is not allowed. This can be prevented by using double screened coaxial cables, as short as
possible e.g. install the modulator and the scrambler next to each other.
There are different ways to connect a scrambler to the P
ULSAR
. The most common are shown in the
figures on the next pages.
If the P
ULSAR
has a built-in stereo coder or is going to be modified to a
stereo device, the REF VID input connector must be installed. Without the
stereo coder this connection is not needed.
Figure 1: The UNSCR VIDEO enters the P
ULSAR
via a BNC T-connector where the signal is
branched to the REF VID input connector in order to separate the sync pulses for locking the pilot on
the stereo coder module. The other direction of the T-connector leads to the scrambler. The scram-
bled signal is connected now to the main input. In this case, there is a different signal connected to
the main (SCR) and the aux (UNSCR) input. The signal on the aux can be e.g. a test pattern.
Figure 2: Basically, the principle is the same as in figure 1, except that the same signal is
connected to the main (SCR) and the aux (UNSCR) input. Remark that on the main input the signal is
scrambled and on the aux input the same signal is unscrambled. One the of the T-connector is still
put on the REF VID input of the P
ULSAR
, while the other side is connected to the aux input. Via the
standard loop through connection (BR21 must be put into the non-default position) of the aux input,
the signal enters the scrambler.
Figure 3: If the scrambler has a loop through, the BNC T-connector is not necessary.
Figure 4: As an option the main input can be made loop through.
Notice that different combinations of these models are possible.
OPTION: MAIN SCRAMBLED/AUX UNSCRAMBLED SUBSTITUTION
ORDER NUMBER: C9825565
REMARK