Sierra Video 507109-00 - Manual (Page 4)

Composite to 270Mbps Video Converter User’s Guide 4
13, position E, a value of 14, and position F indicates a value of 15. Note that some values are not available
for some switches because some values don’t have 256 possible choices. When the limit for such a switch
is reached, the parameter being adjusted will simply stop changing as the switch is moved to larger settings.
Parameter Storage
The present operating values can be stored to EEPROM for the present video standard by setting SWA to
position E and changing SWB to position 1. Note that SWB must CHANGE; even if that means moving it
away from the desired position and back again. The storage to EEPROM occurs when SWA is then moved
OUT of position E. If SWB is set to any value except 1, moving SWA out of position E will NOT result in
parameter storage to EEPROM. Note that separate storage locations exist for all 4 video standards.
Parameter Recall
The present operating values can be recalled from EEPROM for the present video standard by setting SWA
to position F and setting SWB to position 0 or 1. Position 0 recalls factory calibrated settings which cannot
be altered by the user. As SWB is changed, the modules behavior will reflect the parameters previously
stored in the corresponding EEPROM register. Setting SWB to any value except 0-1 will result the recall
of the customer settings for the present standard. The module can automatically load any parameter set upon
power application if SWA is moved OUT of position F after the desired parameter set has be selected with
SWB.
Blanking Adjustments
Vertical and horizontal blanking can be adjusted to remove production or source information which is not
desirable in the outgoing video signal. While vertical blanking is variable in NTSC, horizontal blanking
provided by the incoming digital video signal is always fixed. It is important to remember that this products
vertical blanking line selector extends into areas commonly blanked by the incoming digital video signal,
but that this product will never UN-blank lines of video explicitly blanked by the blanking bits embedded in
the standard video signal.
Vertical blanking adjustments are performed in a spatially contiguous fashion. This means that, as the
blanking control is incremented, lines of video from both fields are unblanked to provide the appearance of
a contiguous, progressive change in the vertical blanking boundary. Note that no blanking adjustment is
provided at the bottom of the active picture.
Horizontal blanking, by definition of the video standards, always eliminates active pixels in the source
material (unless it is set to zero). Because it changes data within the active portion of the video line, these
transitions take place over a number of pixels. If these transitions occurred over a single pixel, the analog
reconstruction filters would ‘ring’, producing ghosting and even sync disruption at each blanking transition.
Values of ‘0’ indicate that the video edge in question is not being modified by the module in any way. All
other values progressively increase the blanking area in 74 nsec. increments using 5 pixel (370 nsec.) long
transitions
Setup Adjustment
The black level, or setup, of the component signal can be varied from its nominal level in 1LSB steps over a
256 LSB range. The factory values for these numbers reflect the nominal setup value for the selected
standard (7.5 IRE units for NTSC, 0 IRE units for Japanese NTSC or PAL).