BAND_PASS

src/filter.js

Constant for bandpass OregonDSP filter creation.

BAND_PASS

Constant for lowpass OregonDSP filter creation.

LOW_PASS

HIGH_PASS

src/filter.js

Constant for highpass OregonDSP filter creation.

HIGH_PASS

amplitude

src/filter.js
amplitude(real: number, imag: number)
Parameters
real (number)
imag (number)

Remove the mean from a seismogram. Subtract the mean from each data point.

rMean(seis: Seismogram): Seismogram
Parameters
seis (Seismogram) input seismogram
Returns
Seismogram: seismogram with mean of zero

gainCorrect

src/filter.js

Apply the frequency independent overall gain to a seismogram. This does not do a full transfer using poles and zero, this only applies the scalar conversion factor to convert counts back to original real world units and update the units.

gainCorrect(seis: Seismogram, instrumentSensitivity: InstrumentSensitivity): Seismogram
Parameters
seis (Seismogram) the seismogram to correct
instrumentSensitivity (InstrumentSensitivity) overall gain object, usually pulled from stationxml
Returns
Seismogram: new seismogram with original units, like m/s and gain applied.

MinMaxMean

src/filter.js
MinMaxMean

Type: {min: number, max: number, mean: number}

Properties
min (number)
max (number)
mean (number)

createButterworth

src/filter.js

Creates a Butterworth IIR filter using the OregonDSP library.

createButterworth(numPoles: number, passband: string, lowFreqCorner: number, highFreqCorner: number, delta: number): any
Parameters
numPoles (number) number of poles
passband (string) type, use constants of BAND_PASS, LOW_PASS, HIGH_PASS
lowFreqCorner (number) low corner frequency
highFreqCorner (number) high corner frequency
delta (number) delta, period, of timeseries
Returns
any: Butterworth IIR filter

createChebyshevI

src/filter.js

Creates a Chebyshev I IIR filter using the OregonDSP library.

createChebyshevI(numPoles: number, epsilon: number, passband: string, lowFreqCorner: number, highFreqCorner: number, delta: number): any
Parameters
numPoles (number) number of poles
epsilon (number) Chebyshev epsilon value
passband (string) type, use constants of BAND_PASS, LOW_PASS, HIGH_PASS
lowFreqCorner (number) low corner frequency
highFreqCorner (number) high corner frequency
delta (number) delta, period, of timeseries
Returns
any: Chebyshev I IIR filter

createChebyshevII

src/filter.js

Creates a Chebyshev II IIR filter using the OregonDSP library.

createChebyshevII(numPoles: number, epsilon: number, passband: string, lowFreqCorner: number, highFreqCorner: number, delta: number): any
Parameters
numPoles (number) number of poles
epsilon (number) Chebyshev epsilon value
passband (string) type, use constants of BAND_PASS, LOW_PASS, HIGH_PASS
lowFreqCorner (number) low corner frequency
highFreqCorner (number) high corner frequency
delta (number) delta, period, of timeseries
Returns
any: Chebyshev II IIR filter

applyFilter

src/filter.js

Applies the filter to the given seismogram.

applyFilter(iirFilter: OregonDSP.filter.iir.IIRFilter, seis: Seismogram): Seismogram
Parameters
iirFilter (OregonDSP.filter.iir.IIRFilter) filter to apply
seis (Seismogram) seismogram to apply filter to
Returns
Seismogram: filtered seismogram

Calculates the envelope, y_i = sqrt( y_i y_i + h_i h_i) where h is the hilber transform of y. The default configuration for the hilbet transform is n=100, lowEdge=.05 and highEdge = 0.95

envelope(seis: Seismogram): Seismogram
Parameters
seis (Seismogram) seismogram to apply envelope to
Returns
Seismogram: seismogram cloned but with data as the envelope

Calculates the hilbert transform using the OregonDSP library with default number of points, n=10 (to yield a 21 pt FIR transform) and default low and high edge of 0.05 and 0.95. Low and high edge are given normalized 0 to 1.

hilbert(seis: Seismogram, n: number?, lowEdge: number?, highEdge: number?): Seismogram
Parameters
seis (Seismogram) seismogram to calculate from
n (number?) optional number of points in transform, default is 10
lowEdge (number?) low edge of filter, normailized to 0-1, default is 0.05
highEdge (number?) high edge of filter, normailized to 0-1, default is 0.95
Returns
Seismogram: hilbert transformed data