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Operating Instructions
1780R-Series Operator’s Manual
3–13
Figure 3–7: 1781R Waveform Graticule
Graticule horizontal scales are divided into 12.7 divisions along the
horizontal line at blanking level. The vertical graduations are scaled
according to measuring units and ranges unique to each system – mV
for the CCIR graticule, and IRE units and percent modulation for
NTSC. A mV scale has been added to the NTSC graticule to
facilitate component measurements. The graticules are also marked
for K-factor tolerances and linear-distortion measurements.
Line-time distortion-NTSC. Line-time distortion is measured using the
graticule box labeled L.D. = 2%, 5%. Any test signal that contains
an 18 ms, 100 IRE bar can be used. To make a measurement, select a
one-line sweep and use the two arrows on the 50 IRE line to position
the bar horizontally. Make sure that the blanking level of the
waveform is on the baseline, and that the bar top passes through
100 IRE at its midpoint. (It may be necessary to use the variable gain
control to normalize the gain.) The box excludes the first and last ms
Operating Instructions
1780R-Series Operator’s Manual
3–13
Figure 3–7: 1781R Waveform Graticule
Graticule horizontal scales are divided into 12.7 divisions along the
horizontal line at blanking level. The vertical graduations are scaled
according to measuring units and ranges unique to each system – mV
for the CCIR graticule, and IRE units and percent modulation for
NTSC. A mV scale has been added to the NTSC graticule to
facilitate component measurements. The graticules are also marked
for K-factor tolerances and linear-distortion measurements.
Line-time distortion-NTSC. Line-time distortion is measured using the
graticule box labeled L.D. = 2%, 5%. Any test signal that contains
an 18 ms, 100 IRE bar can be used. To make a measurement, select a
one-line sweep and use the two arrows on the 50 IRE line to position
the bar horizontally. Make sure that the blanking level of the
waveform is on the baseline, and that the bar top passes through
100 IRE at its midpoint. (It may be necessary to use the variable gain
control to normalize the gain.) The box excludes the first and last ms