Smooth Data

The Smooth Data command, in the Common Tools menu, is used in cases where the acquired data is less than ideal. There are some cases where exterior noise enters the cell and causes the data to have some minor oscillations. The Smooth Data command offers two different types of smoothing algorithms.

• The first algorithm is a sliding-window, which takes a number of data points in a window. This window averages the data points, and then slides one spot over, and again takes an average. This sliding effect is repeated until all the data have been traversed. This technique is simple, but has a downside of changing the heights of peaks.
• The second algorithm is a Savitzky-Golay smoothing filter, a low-pass filter, which helps to preserve higher points by approximating the underlying function with a polynomial. This method requires two parameters: an order, which is the order of the polynomial, as well as a width, which is the number of points to be fit by the polynomial. The defaults of 4 for the order, and 16 for the width are suitable for the majority of applications, but you can easily change them.

To smooth the data:

1. Make the trace you wish to smooth the Active trace. Do this by right-clicking on the trace and clicking Activate Trace.
2. Select the Smooth Data command from the document menu. This opens the Smooth Data window.
3. Select the type of smoothing, and then specify the conditions for that filter.
4. Click the OK button. The smoothing algorithm operates.

One side-effect of smoothing the data is that it, in essence, replaces the original data in the document. To retrieve the original data, you must reload it from the original .DTA file.