Tektronix 2212 Service Manual page 97

NTSC COMPOSITE VIDEO
BOTTOM
I
OF
FIELD
2
6
EQUAL I ZINC
PULSES
6
SERRATED
PULSES
6
EQUALIZING
PULSES
Video Option
RETRACE
I
TOP
BLANKING OF
FIELD 1
~
I-
s2 s-i- 1
-1-
2
-1-
3
-f-
4
-f-
s -+- 6 -+- 7
-f-
s -+- 9 -+- 10-!
I-
22-j
PLL VCO OUT
HCLK
VERTICAL SYNC
BOTTOM
I
OF
FIELD 1
6
EQUALIZING
PULSES
FIELD
1
6
SERRATED
PULSES
6
EQUALIZING
PULSES
RETRACE
I
TOP
BLANKING OF
FIELD 2
~
I-
263-+- 1 -+- 2
-+--
3 -+- 4 -+- 5 -+- 6
-+
7
-+--
8
-+--
9
-1-
10
-I
I-
22-j
PLL VCO OUT
HCLK
VERTICAL SYNC
2212 Service Manual
FIELD 2
Figure 3-9: Timing Diagram from Composite Sync to Trigger Signal
02703B preloads the line selector counter (02709, 02710, 02711) with the
value as written in the control register (02706, 02707) by the main controller.
The preload value reflects the line number that is selected to trigger on.
The line selector counts up, clocked by HORIZCLK_O and produces a RCO.
If TV _EN_O is valid, ALL_LINES is not valid, UNLOCKED is not valid, and RCO
is valid, then the combinatorial logic inside 02708 creates a trigger pulse from
CMPSS (or HCLK after a small delay).
Revised 3/93
3- 39