Using Features for Advanced Applications
3–164 TDS 684A, TDS 744A, & TDS 784A User Manual
Figure 3–96: Peak-Peak Amplitude Measurement of a Derivative Waveform
The settings you make for offset, scale, and position affect the math waveform
you obtain. Note the following tips for obtaining a good display:
You should scale and position the source waveform so it is contained on
screen. (Off screen waveforms may be clipped, resulting in errors in the
derivative waveform).
You can use vertical position and vertical offset to position your source
waveform. The vertical position and vertical offset will not affect your
derivative waveform unless you position the source waveform off screen so
it is clipped.
When using the vertical scale knob to scale the source waveform, note that it
also scales your derivative waveform.
Because of the method the oscilloscope uses to scale the source waveform before
differentiating that waveform, the derivative math waveform may be too large
vertically to fit on screen — even if the source waveform is only a few divisions
on screen. You can use Zoom to reduce the size of the waveform on screen (see
Zoom that follows), but if your waveform is clipped before zooming, it will still
be clipped after it is zoomed.
If your math waveform is a narrow differentiated pulse, it may not appear to be
clipped when viewed on screen. You can detect if your derivative math wave-
form is clipped by expanding it horizontally using Zoom so you can see the
Offset, Position, and Scale