Nevion FRS-HD-XMUX4 - Manual (Page 17)

FRS-HD-XMUX4 Rev. C
nevion.com | 17
5.4.1 Frame sync mode
If a sync input (B&B or Tri-level) is present, the frame synchronizer will output a signal
that has a delay relative to this signal. Two parameters can be set: "Phase delay" and
"Frame delay".
Figure 7: Multicon GYDA view of the video delay settings
Let us first focus on the phase delay , which also may be called “output phase delay”.
This parameter can be positive or negative, and determines the relationship between
the outgoing video and the sync signal.
The phase delay can thus be written in several ways, a large positive delay will equal a
small negative delay, because there is wrap-around on a frame basis. It follows that it
is not useful to specify a phase delay larger than 1 frame. Strictly speaking the range
could have been limited to -1/2 frame to 1/2 frame. For convenience, the delay range is
allowed to be from -1 frame + 1100 samples to 1 frame
– 1100 samples.
In addition to the phase delay, the user may specify additional frames delay. When
frame delay is set to 1 frame, the delay through the card will be between 1 and 2
frames, depending on the input phase between SDI-input and sync input.
The frames and lines are measured in units of the output SDI video standard. If the
output SDI standard is 1080i25, a delay of one line is equal to 35.5us. If the output SDI
standard is 720p50, a delay of one line is equal to 26.6us. If the output SDI standard is
625i25, a delay of one line is equal to 64us.
For a scenario where the card receives different HD video standards, (e.g.
1080i25 and 720p50) the user may want to conserve a specific delay in
microseconds for all HD video standards. This is accomplished by
specifying the delay in number of samples instead of frames and lines. (For
HD video standards the sample frequency is equal over standards, but the
line and frame frequencies are different for the different standards).
If video input disappears
Given that stable SDI input and sync input exists: If the SDI input disappears, the
picture will freeze for <hold time> and then go to video generator if the card is in default
configuration.
If video input reappears
Given stable sync input, the video will reappear after <lock time> of locked video input
if card is in default settings.
If sync input disappears
Given that stable SDI input and sync input exists: If the sync signal disappears, the
card will act as in frame delay mode, see Chapter 5.4.2.
NOTE: This will result in a frame roll as the delay changes.
If sync input reappears
Given that a stable SDI input exists: If the sync signal reappears the delay mode will
change back to Frame Sync mode. Hence the internal clock will be locked to the sync
signal and the delay will again change.
NOTE: This will result in a frame roll as the delay changes.
If both signals disappears