An ideal comb filter is a unit amplitude periodically spaced impulse train
in the frequency domain (Max 1981).
bursts in listed range, where a burst is an impulse train with > 6 and < 200 impulses: ([n.
Consequently, we separated out a particular class of impulse trains, those with > 6 but < 200 impulses separated by intervals < 500 ms, as potential predictors of insect infestation, denoting them as bursts.
The distributions of impulse trains and bursts in six recordings from different insects are shown in Table 1, and examples of several impulse trains denoted as bursts are shown in Fig.
Consecutive larval impulses separated by < 150 ms were grouped together as impulse trains and classified according to the profile matched by a majority of the impulses.
There were 331 larval impulses and 81 noise impulses in this example, and 16 impulse trains met the criterion for larval bursts.
The impulses and impulse trains detected in the recordings were analyzed with customized software, DAVIS (Digitize, Analyze, and Visualize Insect Sounds, Mankin et al.
The beginning and ending times of impulse trains, their labels, and the number of impulses per train were stored in separate train-sequence spreadsheets for each recording.
2008b), it had been determined that particular classes of impulse trains
, denoted as bursts, were good predictors of the presence of insect infestation at a recording site.