Filter
Top Products
MCE User’s Guide Selecting the data file and pre-processing
NM20600A-A 2004-05-17 5
Figure 3 Effect of the baselines
3.2 Decreasing the computing time and file sizes
If you do not calculate estimates at all the time points, you can decrease the
computing time and save disk space.
If you low-pass filter the data, the data will be smoother and it is unnecessary to
calculate the estimate at each time point. By selecting a down-sampling ratio
with the [Decimate] toggle and slider, the estimates will be calculated with
constant intervals.
You can select the correct amount of down-sampling by selecting the [Freq.
response] button. If the down-sampling is too strong compared to the filter
pass-band, the higher frequencies will be mapped to the lower frequencies (see
Figure 4). A reasonable down-sampling ratio is the one, for example, having the
cutoff frequency about half way between the zero frequency and the highest
shown frequency. The down-sampling is carried out by selecting single data
points of the filtered response.
If you do not need to analyze the whole epoch, select the interesting time period
with the [Trim] toggle button and text fields.