Tektronix WFM 601A, WFM 601E, WFM 601M - page 112

Reference
3–56 WFM 601A, WFM 601E & WFM 601M User Manual
Figure 3–39 shows the Lightning graticule with a trace. The target boxes at the
end of each vector indicate a tolerance of ±14 mV. The closely spaced small dots
provide a guide for checking transitions. These dots are spaced 40 ns apart while
the widely spaced dots represent 80 ns. The electronic graticule eliminates the
effects of CRT nonlinearity.
@ 525/2:1
VECTOR
LIGHTNING
40 ns
80 ns
R
G
B
B
R
G
C
C
M
M
YL
YL
Figure 3–39: Lightning graticule showing interchannel timing errors
The three signals are back-porch clamped and identically low-pass filtered to
provide a common point and identical delay through the system. The color
difference signals are line alternated, and the luminance signal is inverted on
alternate lines.
The information available from the Lightning display is color difference signal
accuracy (horizontal displacement of either half of the display), luminance gain
(vertical displacement between the black and white levels), timing delay between
either color difference signal and luminance (bending of the green/magenta
transitions). Figure 3–39 shows the graticule and the measurement targets and
timing delay scales.