Snell & Wilcox HD1012, Руководство по установке

Страница: 21 / 57

www.snellwilcox.com
S&W Production & Post Production HD1012 Installation Manual – V3, Issue 1, Rev 1 Page 13
SYSTEM TIMINGS - continued
Referencing - System Delays
The total delay through the system depends partly on the current standard but mainly on which
cards are fitted to the HD1000 mainframe. The minimum delays for each non-DVE card are shown
below. The delay through the external HD1132 router (when fitted) is a few serial (1.485GHz)
clocks and is therefore negligible.
System Delay Timings
Name Function Optional? Clocks Time (at 74.25MHz clock-rate)
DES Deserialiser No 56 0.75421µs
SRC Sources No 6 0.080808µs
KEY Chroma Keyer Yes 137 1.8451µs
CCR Color Corrector Yes 74 0.99663µs
BDR Border Generator Yes 320 4.3098µs
SWR Switcher No 99 1.3333µs
CPU CPU & Outputs No 24 0.32323µs
Total 716 9.6431µs
The times above are calculated based on the standard 74.25MHz clock rate as used by most HD standards.
For NTSC-timing-compatible standards such as 1080i/59.94Hz that use the 74.25/1.001MHz clock-rate, the
times will be longer by one part in one thousand.
Therefore with all options fitted, the minimum delay through the system is 716 clocks (9.6431µs),
as shown above. With no options fitted, the minimum system delay is 56 + 6 + 99 + 24 = 185
clocks (2.4916µs); the BYPass card that replaces a non-fitted option card incurs no clocks.
This minimum delay will, of course, only be achieved if all the input sources are timed
appropriately. As shown on the previous page, sources can arrive over 47 to 79 lines (depending
on line-standard) earlier than required and still be synchronised correctly.
If a source arrives outside the timing window, i.e. too early, or closer to output timing than the
system’s minimum delay, then the source will appear horizontally as well as vertically displaced.
For example, with a fully-optioned system, this will happen if the source arrives later than 716
clocks before the output or earlier than (716) clocks before the output.
The Border Generator has the ability to add up to 20 lines of delay to all paths (see the description
of the
Configure - System - System Delays menu in the User Manual for more information about
this). For the duration of a line in microseconds, see page 9. Any delay added in this fashion will
not affect the input window if the machine is being genlocked to an external source - instead the
output will be delayed. However, if the sources are locked to the Ref Sync Output, this adjustment
will eat into the timing window, and the
Ref Sync Out put’s Sync H/V-Phase controls may need to
be adjusted.
Any signals sent through a DVE will be delayed by precisely one extra frame.