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Engineering using Spreadsheets

Function Analysis: Example 3

Description
How it works
Examples:
Reaction Kinetics
1-D Random Walk
Analysis of Noisy Data








Analysis of Noisy Data

In many engineering and scientific studies, data is obtained from a system or process using sensors. These data typically contain noise. In this example, we look at the difficulty of fitting this data to a differential model using numerical differentiation.

The function we plot is =RAND() from 0 to 1, the constant of integration is 0. This function simulates random noise on a DC signal of magnitude 0.5. The plot of the function looks like this:

Random Noise

The first derivative of the data is shown below:

Noisy data derivative

Note that the derivative is even noisier than the source data. In comparison, the integral plot is smoother. It is close to a straight line with slope = 0.5, suggesting that it might be better to look at the integral of the data to look for underlying structure.

Integral of noisy data