eldo_user

Eldo Control Language
Library of Functions for Tasks
• sampling
Specifies the method of computing the sampled data. Valid values are “No Sampling” or
“Interpolation”.
• padding
Activates data padding to pad the input data with zeros, before or after the input data set.
Valid values are: “No Padding”, “Padding Right”, “Padding Left” or “Padding Left and
Right”. The input parameter will be verified by the algorithm and changed if necessary.
• averaging
Specifies whether you want to take an average on the raw data to reduce noise and smooth
the frequency domain waveform. Specify 1 to turn this on, or 0 to not modify the raw data
from calculation.
• windowing
Applies a windowing function from a selection of windows. Valid values are:
“Rectangular”, “Hamming”, “Hanning”, “Parzen”, “Welch”, “Blackman”, “Blackman-
Harris”, “Bartlett”, “Kaiser”, “Klein” or “Dolph Chebyshev”.
• windowing_arg
Specifies the alpha or beta value that is required by “Hanning”, “Kaiser”, and “Dolph
Chebyshev” windows.
• reference_frequency
Adjusts the results around the y-axis so that the point for the specified frequency is 0.0.
• minimum_frequency
Specifies the starting frequency used inside the Fast Fourier Transform result window.
• maximum_frequency
Specifies the last frequency used inside the Fast Fourier Transform result window.
Description
For symmetric windows, the parameters above satisfy the following equation:
((number_of_points) / sampling_frequency) = time_stop - time_start.
For periodic windows, the parameters above satisfy the following equation:
((number_of_points-1) / sampling_frequency) = time_stop - time_start.
For “Hanning”, symmetric window shapes are preferred when using a Hanning window in FIR
filter design. Periodic window shapes are preferred when using a Hanning window in spectral
analysis. This is because the Discrete Fourier Transform assumes periodic extension of the
input vector. A periodic Hanning window is obtained by constructing a symmetric window and
removing the last sample.
Eldo® User's Manual, 15.3 897