NI Spectral Measurements Toolkit User Guide 26 ni.com
Averaging Options
Figure 10 illustrates the options available for spectrum averaging.
Figure 10. Spectrum Averaging Options
The averaging processes apply weighting to the < > operator in both RMS
and vector averaging as shown in the following equation:
Yk = <X>k = a1 × Yk – 1 + a2 × Xk
where Yk is the new average, Yk – 1 is the previous average, and Xk is the new
measurement.
For linear weighting,
a1 = (k – 1)/k, and a2 = 1/k
For exponential weighting,
a1 = (k – 1)/k and a2 = 1/N for k ≤ N,
a1 = (N – 1)/N and a2 = 1/N for k > N
where N is a user-specified constant that determines how much weight
is given to recent data relative to older data. Small values of N place more
Exponential
Average Size
Peak-HoldNo Averaging VectorRMS
Averaging
Type
Linear
Weighting
Type
Linear
Weighting
Mode
Moving Average
Auto Restart ContinuousOne Shot