Grass Valley PDR v.2.2 - Manual (Page 56)

Chapter 2 Using the Profile Configuration Manager
38 Profile Family
• Comb Filter. Decode mode tries to separate high frequency luminance from
the chrominance using the same notch filter as the notch decoder, but also
takes information from the next line. It uses this information to determine if
high frequency is luminance or chrominance. A comb decoder readily
determines finely spaced vertical lines are luminance. A lack of line-to-line
phase alteration causes difficulty with fine horizontal lines.
• Spatial Adaptive. Decoding uses either the comb or notch decoder, on a
pixel by pixel basis, depending on which gives the best results. For
horizontal lines, notch is used; for vertical lines, comb is used.
NOTE: Spatial adaptive decoding uses the high or low threshold
setting.
Clamp Speed
Clamp speed sets the reaction to changing DC levels of the input signal. Click
Enable Clamp Speed to enable it. Speed can be either slow or fast. The fast
clamp speed is more reactive to small DC variations. The slow speed ignores
short-term DC level changes but gradually changes the clamping level to track
the input.
Vertical Interval
These controls set how vertical interval signals are handled. Move the Group
Definition slider to set how many lines are in Groups 1 and 2. In Group 1, Notch
and Pass are available while Blank and Pass are available in Group 2:
• Notch applies notch filtering to the vertical interval video line. This means
that chrominance information and any luminance around the chroma
subcarrier are removed.
• Pass indicates that the vertical video line is passed-through.
• Blank indicated that line the group are blank.