Tektronix 1760 series, User Manual

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Basic Measurements
1760 Series Component Waveform/Vector Monitor User Manual
4-18
of checking timing. The signal source can be adjusted until
the ellipse disappears, providing a very accurate method of
correcting timing errors.
Timing errors are indicated by the trace moving away from
the center timing dot. See Figure 4-15. For wide-band (
≥
1.5
MHz) component formats, the smaller spacings of dots repre-
sent approximately 40 ns of error; the larger spacing repre-
sents 80 ns. The timing dots represent proportionally larger
errors for lower bandwidth signals.
For signals decoded from composite (bandwidth of approxi-
mately 500 kHz), the timing dots represent approximately
120 and 240 ns, respectively. The transitions will be “S”
shaped due to the narrow-band color difference signals. Note
that correct timing is always indicated by a transition through
the center dot, regardless of the signal bandwidth.
If a trace appears “bent” toward the center of the display,
delay of the color difference signal is indicated. “Bending”
away from center indicates an advance of the color differ-
ence signal relative to luminance.
C
M
B
R
M
C
G
B
R
G
YL
YL
Approximate 80 ns
delay of Channel 2.
Figure 4-15.
Lightning display showing delay.