SS0607-8
30 September 1988
studio is being driven by a reference-synchronizing generator that will
adjust the timing of that entire studio. Each source cluster is driven by a
source-synchronizing generator so that the source cluster timing will stay
together.
The reference output from each studio reference-synchronizing
generator is sent to the routing switcher.
The reference input to any
source-cluster-synchronizing generator can be assigned to any studio. This
automatically times the source cluster to the studio using it.
If the
reference-synchronizing generator has a phase preset installed, the phase
setting for every configuration can be stored and recalled.
A typical
configuration could be source cluster 1 timed into studio 1, the output of
studio 1 and source cluster 3 timed into studio 2, source cluster 2 timed
into studio 3, which is also a timed input to studio 2.
These timing
assignments can easily be interchanged with the phase preset and routing
switcher once the initial timing is completed and stored in each reference-
synchronizing generator.
a. This system provides maximum flexibility in tailoring each studio
for the production it is to be used for. The cameras would be assigned to a
studio doing live production and the video tape machines could be used for
post production in another studio. Many more sources can be added by using
this design without causing major system design problems.
b. Distributed synchronizing generator systems also provide redundancy,
which is an important advantage.
Should a failure occur in the master
generator, the reference and source generators will free run. The free run
action will keep the equipment functioning.
Learning Event 2:
DESCRIBE THE PROBLEMS AND DEFINE SOLUTIONS OF SC/H PHASE
1.
In the late 1940s the Electronic Industries Association (EIA)
established monochrome television standard RS170.
In recent years the
proposed color standard RS170A has received increasing acceptance. RS170A
fully outlines the phase relationship of the color subcarrier to horizontal
sync. A graphic representation of this standard is included in Figure 2-3,
p. 16.
If we look at the equation that relates horizontal sync to
subcarrier and consider the number of lines in each frame, several
conclusions can be made.
H = 2 X 3.579545
455
2.
First, there are 227.5 subcarrier cycles per horizontal line; so,
subcarrier phase reverses every line.
This is desirable to reduce the
visibility of color subcarrier on monochrome receivers.
Second, with 525
lines per frames, there are 119437.5 subcarrier cycles in each frame.
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