<series> output = <series>.filter(<string>Filter Type, <number>Cutoff Frequency)
<series> output = <series>.filter(<string>Filter Type, <number>Low Cutoff Frequency>, <number>High Cutoff Frequency)
The filter function applies a finite impulse response (FIR) filter to the input data. This function can be called with either two arguments or three arguments. For a High Pass Filter, use two arguments with “HP” Filter Type. For a Low Pass Filter, use two arguments with “LP” as Filter Type. For a Band Pass Filter, or a Band Stop Filter, use three arguments with “BP” or “BS” as Filter Type, respectively. The FIR filter kernel width is 101, and a Blackman window is used to smooth non-linearity at the edge of the filter kernel.
Examples:
var mySeriesLPF = mySeries.filter(“LP”, 500); // attenuate frequencies greater than 500 Hz
var mySeriesHPF = mySeries.filter(“HP”, 500); // attenuate frequencies less that 500 Hz
var mySeriesBPF = mySeries.filter(“BP”, 250, 750); // attenuate frequencies
var mySeriesBSF = mySeries.filter(“BS”, 250, 750);