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greenMachine callisto Reference Manual - Rev 1.5
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Frame Synchronization
The algorithms used for frame synchronization are extremely robust and very tolerant of poor
input signals. The Synchronizer uses “Flywheel” functionality. This allows the module to recover
from any missing sync pulses on the input signal(s) by predicting where they should be and then
re-inserting them.
If no converters are active, the frame synchronizer passes the video in the connected input
format.
Reference Source
The frame synchronizers can be referenced by the external reference input or either one of the
video processing paths. The reference source is a global setting i.e. both frame synchronizers
use the same reference source and can’t be set individually.
If the reference source is set to external reference and no external reference is connected, the
frame synchronizer is in free run mode.
TRS Error Behavior
In addition to synchronizing the video signal(s) to the reference source the frame synchronizers
can also detect TRS errors of the video signal. The frame synchronizers can individually be
configured to either ignore the TRS error or to freeze on TRS error. The freeze behavior is
determined by the freeze mode setting.
Freeze Mode
The Freeze Mode determines the behavior of the individual frame synchronizers when
set to “Freeze on TRS” and detecting a TRS error on the processed video signal.
Possible selections are:
- Freeze Field 1
Only Field 1 will be frozen and output. This only applies for interlaced standards. For
progressive standards the frame synchronizer will automatically freeze frame.
- Freeze Field 2
Only Field 2 will be frozen and output. This only applies for interlaced standards. For
progressive standards the frame synchronizer will automatically freeze frame.
- Freeze Frame
The frame synchronizer will freeze the frame on TRS error.
- Test Pattern
When detecting a TRS error the frame synchronizer will output a test pattern. The
test pattern is identical to the one selected for the test pattern generator.
This setting is ideal to identify TRS errors on the video signal.
Output if no Input
This setting determines the behavior of the frame synchronizer if the processed video input signal
is lost. Three possible selections are available.
- Freeze (outputs the last frame)
- Black (outputs a black signal)
- Test Pattern (outputs the selected test pattern)