Tektronix 1710J Series, Instruction Manual

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Reference
1710J-Series Waveform Monitors
3–5
NOTE . For signals with a bar half-amplitude duration (HAD) that exceeds 8
m
s,
simply measure the bar top in increments by positioning the bar to the left or
right from the leading or trailing edge. Note that when the leading and trailing
edge is on the appropriate arrow, the first or last 1
m
s is automatically excluded
from the measurement.
Pulse-to-bar K-Factor measurements are made using the solid and short dashed
lines to the right of the line time distortion structure. These lines are scaled to the
following formulas:
1
(1–4K)
and
1
(1
)
4K)
Where:
K=0.02 for 2% K-Factor (dashed lines)
K=0.04 for 4% K-Factor (dashed lines)
Calibrated 5X Gain increases resolution to 0.4% and 0.8%.
This scaling is described in detail in CCIR Standard Volume 5, 1966.
Make sure that the center of the bar is at 1.0 when blanking level is at 0.3. If
necessary, use the HORIZONTAL Position control to place the 2T pulse over the
measurement area and measure its amplitude. The top of the pulse falling within
the dashed lines equals less than 2% K-Factor.
Analyzing a Video Signal
Although television test equipment and test signals have evolved over the years
to make video quality monitoring fast and easy, an experienced operator can keep
the signal under tight control using just a waveform monitor.
A television system works well over a wide range of conditions because the
destination equipment knows what to expect and makes a final presentation on
the viewing screen based on how the signal follows the rules. A part of the signal
is very specific in controlling the operation of the receiving device and a part of
the signal is free-form, where visual effects are created for the screen display.
Because the controlling elements are closely specified, an experienced operator
can use this part of the signal to observe distortions in the transmission system
and predict the effect on the creative part of the signal.
Characteristics of the controlling parts of your video signal can help you read the
quality of your system. The specific times set aside for this controlling signal are
known as the horizontal and vertical blanking intervals. Both intervals contain
valuable clues to system performance.
The Test Signal in the
Video Signal