Math waveform differentiation
The math capabilities of the instrument include waveform differentiation.
Waveform differentiation allows you to display a derivative math waveform that indicates the instantaneous rate of change of the acquired
waveform.
Derivative waveforms are used in the measurement of slew rate of amplifiers and in educational applications.
The math waveform, derived from the sampled waveform, is computed based on the following equation:
Where: X is the source waveform, Y is the derivative math waveform, and T is the time between samples.
Since the resultant math waveform is a derivative waveform (see the next figure), its vertical scale is in volts/second (its horizontal scale is
in seconds). The source signal is differentiated over its entire record length; therefore, the math waveform record length equals that of the
source waveform.
Math waveform offset position and scale
The settings that you make for offset, scale, and position affect the math waveform you obtain.
Here are some tips for obtaining a good display:
• Scale and position the source waveform so that it is contained on the screen. (Off-screen waveforms may be clipped, resulting in errors
in the derivative waveform).
• Use vertical position and vertical offset to position your source waveform. The vertical position and offset will not affect your derivative
waveform unless you position the source waveform off screen so that it is clipped.
Waveform integration
The math capabilities of the instrument include waveform integration.
This allows you to display an integral math waveform that is an integrated version of the acquired waveform.
Use integral waveforms in the following applications:
• Measuring power and energy, such as in switching power supplies.
• Characterizing mechanical transducers, as when integrating the output of an accelerometer to obtain velocity.
The integral math waveform, derived from the sampled waveform, is computed based on the following equation:
Measurement concepts
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