Grass Valley LGK-3901 - Manual (Page 22)

GUIDE TO INSTALLATION AND OPERATION
16 | LGK-3901/DSK-3901
4.4 Reference
4.4.1 Reference Types
The LGK-3901/DSK-3901 will lock to one of the following inputs, in order or priority:
• Universal Reference Signal (URS) from a Densité REF-1801, if present and enabled
• REF IN Analogue Reference Input, if present and compatible
• PGM IN, if present and at the correct video standard
• Otherwise the card will free-run
The compatibility matrix between REF IN type and output video format is shown below:
REF IN Type
525i / 59.94
625i / 50
1080i / 59.95
1080i / 50
720p / 59.94
720p / 50
525i / 59.94 ›
625i / 50 ›
1080i / 59.94 › ›
1080i / 50 › ›
720p / 59.94 › ›
720p / 50 › ›
1080p / 59.94 ›
Outpu
t Vide
o Format
1080p / 50 ›
4.4.2 Adjusting Reference Timing
Note: Reference timing should always be adjusted off-air since it can result in a loss of picture in downstream
equipment. Errors may occur in the SDI stream whilst the adjustment is taking place.
The reference offset can be modified via the front panel menu SETUP > REFERENCE > OFFSET in the either:
• Lines and Samples
• Lines and µs
Use the joystick arrows [+] and [–] to increase or decrease the offset value. For any video standard the factory default
reference timing is 0 lines plus half the length of a video line. This will buffer about half a video line for inputs that are
timed to a reference offset of + 0 lines + 0 samples (or + 0 lines + 0 µs).
Reference adjustment affects the line number marking of the output stream. It needs to be adjusted to match the input
signal timing of the local facility. Ancillary data such as timecode, captions and audio metadata may be missed by
downstream equipment if they are not present on the same line that they were input on. If the output reference timing
is not set correctly then problems may be seen such as: