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3.12 Applying the FIR filter

Use the Decision level (V) slider to return the decision level to midway between 0 and 1, then click on Apply. Confirm that the statistics are as would be expected; that is, correct detections of 1s and 0s are at approximately the same percentage. The correct detection percentages do not need to be identical, but try to get them to within about 1% of each other by adjusting the detection level.

You are now going to apply the FIR filter. In the top right zone, set the FIR filter width (number of samples) slider by eye to around 30–40 samples, then click on Apply.

Activity 12

• a.Compare the top right zone (histogram and statistics before filtering) to the bottom right zone (histogram and statistics after filtering). What effect has the filter had on the statistics for correct detection?
• b.Explain any difference in detection statistics between those beneath the unfiltered signal and those beneath the filtered signal.