• Variables
Dependencies
In general, math waveforms that include sources as operands are affected by updates to those sources:
• Shifts in amplitude or DC level of input sources that cause the source to clip also clip the waveform data supplied to the math
waveform.
• Changes to the vertical offset setting for a channel source that clips its data also clips the waveform data supplied to the math
waveform.
• Changes to the acquisition mode globally affects all input channel sources, modifying any math waveforms using them. For example,
with the acquisition mode set to Envelope, a Ch1 + Ch2 math waveform will receive enveloped channel 1 and channel 2 data, and will
also be an envelope waveform.
• Clearing the data in a waveform source causes a baseline (ground) to be delivered to any math waveform that includes that source
until the source receives new data.
Guidelines for working with math waveforms
Remember guidelines when working with math waveforms.
Use the following guidelines when working with math waveforms:
•
Keep math waveforms simple.
•
Math calculations are not available on digital channels.
•
To avoid syntax errors in a math expression, verify the use of operators, parentheses, operands, and the spelling of functions.
• If one or more reference waveforms are used in a math waveform, the record length is equal to the smallest of all the source
waveforms (reference or channel waveforms). The math is calculated using the first point from each source, followed by the next point,
and so forth. This is true even if the sources have different times between points in the record.
Math waveform editor syntax
You can build math waveforms using the predefined expressions or the equation editor.
To help you create valid math waveforms, the following tools block most illegal entries by disabling any window element that would create
an invalid entry in the math waveform expression.
Predefined expressions are accessible using the FFT or Basic Math Types.
The following syntax describes the valid math expressions you can use with the Equation Editor for the Advanced Math Type:
A math expression is composed of settings, functions, scalars and sources.
Functions, except for basic and logic functions, have the syntax function(source).
Basic and logic functions have the syntax source1 function source2.
Examples: Ch1 * Ch2
Ch1 >= Ch2
Logic functions, ==|<|>|!=|<=|>= result in a waveform consisting of binary 0 and 1 values.
Scalars can be integers, floating point values, PI or meas<x>.
Sources can be Ch<x> or Ref<x>
Measurement concepts
3 Series Mixed Domain Oscilloscope Printable Help
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