Tektronix 1730 Series, Instruction Manual

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1730–Series Operating Instructions
2–24
0V
1.2
1.0
1.1
0.9
0.8
0.7
0.6
0.5
0.4
0.2
0.1
0
PAL
–0.3
+0.7
Tek 2% & 4% K FACTOR
Figure 2-17: PAL graticule.
The boxed area slightly to the left of center at the 1.0 V level is scaled for 2%
and 4% K–Factor ratings for precise tilt measurements. This structure is
designed to work with an 8
m
s, half–amplitude duration (HAD) bar. The short
dashed lines to the right of the bar tilt measurement structure are used to measure
pulse–to–bar ratio; they are weighted for 2% and 4% K–Factor ratings.
There are 2% and 4% markings near the horizontal center of the graticule on the
0 V line (sync tip level) to assist in measuring sync amplitude. The dashed
horizontal line at the top of the graticule is equal to 1.234 V to indicate peak
amplitude of 100% color bars. Between the 0.9 V and 1.1 V lines, there are
markings at 20 mV intervals.
Making Measurements. To use the PAL vertical scale for measuring the
K–Factor for line time distortion and pulse–to–bar ratio measurements, set the
signal blanking level at the graticule blanking line (0.3 V) and position the
leading edge of the bar to the ascending arrow, just right of graticule center.
Check to see if insertion gain is unity. If it is not, adjust the 1730–Series VAR
for exactly 0.7 V of signal amplitude from baseline to middle of the white bar.
Check to see that the negative–going bar transition passes through the descend-
ing arrow.
To measure the K–Factor for line time distortion, measure the largest deviation
of the bar top (tilt or rounding) within the structure. The structure is designed to
ignore the first and last 1
m
s of the bar where short–time distortions (ringing,
overshoot, undershoot, etc.) occur. The solid outer box equals a 4% K–Factor,
while the dashed line inner box equals 2% line time K–Factor. (For signals with
a bar half–amplitude duration (HAD) that exceeds 8
m
s, simply measure the bar