Tektronix WFM 601A, WFM 601E, WFM 601M - page 91

Reference
WFM 601A, WFM 601E & WFM 601M User Manual 3–35
K-Factor Graticule. A special graticule located at the top of the etched graticule
allows measurement of K-Factor line-time distortion. Figure 3–26 shows the
special graticule and how to align a 2T Bar waveform to measure time-line
distortion.
The graticule does not include the first and last 1 ms 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 a 2% K factor.
K-factor
graticule
Waveform
alignment
points
Figure 3–26: Graticule for K-factor measurements
To measure the K-factor distortion follow these steps:
1. Apply a 700 mV 2T bar signal with a 26 ms duration bar to the active Serial
input.
2. Adjust the waveform so its bottom is on the 0 V line and its top is on the
700 mV line. If necessary, adjust the Variable Gain in the GAIN menu so the
waveform spans the 0 V to 700 mV lines. Note the rising and falling edges of
the waveform must align with the marks on the 50% line.
3. After initial alignment, measure the largest deviation of the bar top (tilt or
rounding) using the K–factor graticule. You can expand the waveform by
setting Gain to X5. The K factor graticule lines then measure 0.8% and 0.4%
K factor.