Risetime Measurement - PeakTech 2035 Bedienungsanleitung

(b) Lissajous-Patterns of various Phase Angles
Figure 2-11: Dual-Trace Method of Phase Measurement
6. Precisely center the trace horizontally with the Horizontal POSITION control (10).
7. Count the number of divisions subtended by the trace along the central vertical gratitude line
(dimension B). You can now shift the trace vertically with CH 2 POSITION control to a major
division line for easier counting.
8. The phase difference (angle z) between the two signals is equal to the arc sine of dimension A ÷
B (the Step 7 number divided by 6). For example, the Step 7 value of the figure 2-9 a pattern is 2.
Dividing this by 6 yields .3334, whose arcsine is 19.5°.
9. The simple formula in Figure 2-9 a works for angles less than 90°. For angles over 90° (leftward
tilt), and 90° to the angle flound in Step 7.
Figure 2-9 b shows the Lissajous patterns of various phase angles; use this as guide in
determining wether or not to add the additional 90°.
Note: The sine-to-angle conversion can be accomplished by using trig tables or a trig calculator.
2.3.5

Risetime Measurement

Risetime is the time for the leading edge of a pulse to rise from 10 % to 90 % of the total pulse amplitude.
Falltime is the time required for the trailing edge of a pulse to drop form 90 % of total pulse amplitude to
10 %. Risetime and falltime, which may be collectively called transition time, are measured in essentially
the same manner.
Fig. 2-10: Lissajous Method of Phase Measurement
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