User Report: by Terry Brown
nVision SG4424 HD Sync Synchronization Generator
HOLLYWOOD Founded in 1982, LaserPacific Media Corp. is a
digital HD motion picture and television post production facility
offering a full range of services. From the first, LaserPacific
made a commitment to introducing all-digital technological solutions
to the Hollywood community.
The development of our innovative High-Definition Laboratory-which
opened in 1998 and focused on 24p HDTV acquisition, editing and
delivery-enabled our clients to make a relatively painless transition
from standard-definition to high-definition.
 |
| Terry Brown, vice president of engineering
for LaserPacific, poses with the facility's master control reference
system that includes two nVision NV4000 frames holding five
SG4424 HD slave sync generator cards. |
A critical component for the successful high-definition operations
of our plant was a slave sync/pulse generator that could output
all the necessary reference signals needed to synchronize the various
ATSC formats in use. We also needed a sync generator that had some
very specific relationships between 30 fps and 24 fps frame rates.
Since there were no 24p systems available off-the-shelf, LaserPacific
partnered with a number of manufacturers, including nVision, to
develop the critical components. At the same time, nVision was looking
at the task of enabling its digital video routers to have vertical-interval
switching of signals running at different temporal rates.
THE NEXT GENERATION
We started working with nVision to design a "next generation"
sync generator. It was our task to define the various reference
signals anticipated being used within our facility, and we worked
closely with nVision's engineering staff, including Bob Hudelson,
Chuck Meyer and Birney Dayton, to determine what the relationship
of the sync components should be.
The result was the SG4424 HD Slave Sync Generator, which we installed
as a prototype in late-1998, plus subsequent production-version
updates and enhancements since that time. The SG4424 is designed
to lock to an external NTSC or PAL reference signal from the master
sync generator.
Internal jumpers let us select either Hi-Z or 75-Ohm impedance
for the loop-thru PAL/NTSC references, as well as the type of HD
sync format we need, including 1080i/60, 1080i/50, 1080p/30, 1080p/25,
1080p/24 and 720p/60, in the appropriate 0.1 percent offsets. Front-panel
LEDs light when a valid signal is connected to the NTSC or PAL reference
inputs, and when the module's outputs are locked to the selected
reference input.
We now have a total of two NV4000 Series frames in our master control
reference systems area, with a total of five SG4424 cards. This
configuration provides us with eight NTSC/PAL sync reference sources,
some of which are duplicated to provide redundancy. We distribute
these sync sources via a dedicated router to approximately 100 destinations
within our Hollywood plant.
A 24/7 OPERATION
To date, the system has proved to be completely reliable, a performance
record that is essential for a 24/7 operation like ours. The SG4424
is total workhorse, and has been very solid since we first started
to use it back in 1999-but, there again, all our nVision components
have been extremely reliable.
Thanks to companies like nVision, we were able to fast track solutions
for our 24p infrastructure, giving us a one-year head start in the
industry. The nVision SG4424 HD Slave Sync Generator has become
a totally integrated part of how we do business here at LaserPacific.
Terry Brown is the vice president of engineering for LaserPacific
Media. The opinions expressed above are the author's alone.
For more information, contact nVision at 530-265-1000 or visit
www.nvision1.com
|
