Sony Tektronix WFM 1125, User Manual

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Reference
3-18
WFM 1125 Option 0A/0B/0C/0D User Manual
The scale (sequence of dots) between the green and magenta targets provides a
way to check interchannel timing (CH-2 to CH-1 and CH-3 to CH-1) or signal
delay. If the color difference signal is not coincident with luminance, the
transitions between color dots will bend. The amount of this bending represents
the relative signal delay between luminance and the color difference signal. The
upper half of the display measures the P
b
-to-Y timing, while the bottom half
measures the P
r
-to-Y Timing. If the transition bends in toward the vertical center
or black region, the color difference signal is delayed with respect to luminance.
If the transition bends out toward white, the color difference signal is leading the
luminance signal.
The horizontal deflection of the top half of the display is an indication of the P
b
gain and the lower half indicates the P
r
gain. If the color bar signal dots are
within the horizontal dimensions of the appropriate graticule targets, the P
b
and
P
r
gains are within 2% of the correct amplitude.
Since the vertical and horizontal dimensions of the graticule target boxes indicate
2% luminance and color difference gain errors, respectively, you can evaluate
each color bar for encoding accuracy with these limits. The Lightning display
shows the relative level or coding accuracy for Y, P
b
, and P
r
for each of the eight
primary colors much better than the Parade display mode.
Parade Display
This mode displays the component signals Y (CH 1), P
b
(CH 2), and P
r
(CH 3)
one at a time, two at a time, or all three waveforms at once. Measure the
waveforms using the graticule or Cursors.
Gain selections operate as they do in the Waveform display mode and are
available to expand the waveforms vertically to aid in measurement.
Press the OVERLAY/PARADE button on the front panel once or twice so as to
light the PARADE indicator.
Figure 3–13 shows how the waveforms in parade display mode appear on the
graticule.
Interchannel Timing
Measurement
Pr and Pb Gain
Measurement