Amplitude Spectral Density function, which supports blocks, windows, overlap, and averages.


asdcal(vec_expr_1, vec_expr_2, type, block_size, overlap, mean-correction, window, averaging method)


The time vector of the curve.
The magnitude vector of the curve.
A parameter that specifies the type of Amplitude Spectral Analysis that needs to be performed.
0 - Normalized FFT curve with True values as output across frequencies.
1 - Normalized FFT curve with RMS values as output across frequencies.
Note: A sine wave with amplitude 1 as the true value will have an RMS of 0.71.
3 - Power spectral density across frequencies.
The number of elements to be used for each FFT (should be a power of 2).
The minimum block size allowed is 32.
The maximum block size allowed is 131072.
The number of elements shared between consecutive blocks. This value is a percentage.
Determines if the mean has to be subtracted from the curve block or not.
0 - retain the mean of the curve block.
1 - subtract the mean from the curve block.
Specifies the window type that needs to be applied to the curve block.
0 - Rectangular
1 - Hanning
averaging method
Specifies the type of output needed across the block.
0 - Maximum value of amplitude for a given frequency is output.
1 - Average value of amplitude for a given frequency is output.


Curve Math Vector Result
x = freq(c1.x[0:4095:1])
Given c1, the amplitude spectrum of type FFT magnitude with true values is created. The parameters set are as follows:
  • Block - 4096
  • Overlap - 75%
  • Mean correction applied to each block.
  • Window used is rectangular.
  • Output shown is average across blocks.
y = asdcal(c1.x,c1.y,0,4096,75,1,0,1)