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GENNUM CORPORATION
27360 - 2
28 of 55
G
Figure 8 Switch Line Locking
The ability to manually re-synchronize the flywheel is also
important when switching asynchronous sources or to
implement
other
non-standardized
functions.
video
switching
The GS1560A also implements automatic switch line lock
handling. By utilizing the synchronous switch points defined
by SMPTE RP168 for all major video standards with the
automatic video standards detect function, the device
automatically re-synchronizes the flywheel at the switch
point.
This function will occur regardless of the setting of the
FW_EN/DIS pin.
The switch line is defined as follows:
For 525 line interlaced systems: re-sync takes place at
the end of lines 10 & 273.
For 525 line progressive systems: re-sync takes place at
the end of line 10.
For 625 line interlaced systems: re-sync takes place at
the end of lines 6 & 319.
For 625 line progressive systems: re-sync takes place at
the end of line 6.
For 750 line progressive systems: re-sync takes place at
the end of line 7.
For 1125 line interlaced systems: re-sync takes place at
the end of lines 7 & 568.
For 1125 line progressive systems: re-sync takes place
at the end of line 7.
A full list of all major video standards and switching lines is
shown in Table 4.
NOTE 1 : The flywheel timing will define the line count such
that the line numbers shown in Table 4 may not correspond
directly to the digital line counts.
NOTE 2: Unless indicated by SMPTE 352M payload
identifier packets, the GS1560A will not distinguish between
50/60 frames PsF and 25/30 frames interlaced for the 1125
line video systems; 24 PsF will be identified.
EAV
ANC
ACTIVE PICTURE
EAV
ANC
SAV
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
Video source 1
EAV
ANC
ACTIVE PICTURE
EAV
ANC
SAV
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
ACTIVE PICTURE
EAV
ANC
SAV
Video source 2
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
DATA IN
ACTIVE PICTURE
EAV
ANC
SAV
ANC
ACTIVE PICTURE
EAV
ANC
SAV
Switch point
Flywheel TRS
position
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
ANC
ACTIVE PICTURE
DATA OUT
ACTIVE PICTURE
EAV
ANC
SAV
EAV
ANC
SAV
FW_EN/DIS
switch video source 1 to 2
Flywheel re-synch
EAV
ANC
ACTIVE PICTURE
EAV
ANC
SAV
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
Video source 1
EAV
ANC
ACTIVE PICTURE
EAV
ANC
SAV
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
ACTIVE PICTURE
EAV
ANC
SAV
Video source 2
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
DATA IN
ACTIVE PICTURE
EAV
ANC
SAV
ACTIVE PICTURE
EAV
ANC
SAV
Switch point
Flywheel TRS
position
EAV
ANC
ACTIVE PICTURE
SAV
EAV
ANC
SAV
ACTIVE PICTURE
DATA OUT
switch video source 2 to 1
EAV
ANC
SAV
ACTIVE PICTURE
EAV
ANC
SAV
Flywheel re-synch
FW_EN/DIS