Noise

Utilities for detector and environmental noise models, including ASD helpers and time-domain synthesis. The gwexpy.noise module is organized into two submodules:

gwexpy.noise.asd: Functions that return Amplitude Spectral Density (FrequencySeries)
gwexpy.noise.wave: Functions that return time-series waveforms (TimeSeries)

gwexpy.noise.asd

Functions for generating Amplitude Spectral Density. All functions return FrequencySeries.

Detector Noise Models

Function	Description
`from_pygwinc(ifo, *, quantity='strain', fmin=10, fmax=8192, df=1.0)`	Generate ASD from pyGWINC detector noise models (aLIGO, AdV, etc.)
`from_obspy(model, *, quantity='displacement', fmin=0.01, fmax=100)`	Generate ASD from ObsPy seismic noise models (NLNM, NHNM)

Colored Noise ASD

Function	Description
`power_law(exponent, amplitude=1.0, f_ref=1.0, frequencies=...)`	Generate power-law ASD (f^-exponent)
`white_noise(amplitude=1.0, frequencies=...)`	White noise ASD (flat spectrum)
`pink_noise(amplitude=1.0, frequencies=...)`	Pink noise ASD (1/f^0.5)
`red_noise(amplitude=1.0, frequencies=...)`	Red/Brownian noise ASD (1/f)

Geomagnetic Noise Models

Function	Description
`schumann_resonance(harmonics=8, frequencies=...)`	Schumann resonance model (~7.83 Hz and harmonics)
`geomagnetic_background(frequencies=...)`	Background geomagnetic noise model

Spectral Line Shapes

Function	Description
`lorentzian_line(center, width, amplitude=1.0, frequencies=...)`	Lorentzian line shape
`gaussian_line(center, sigma, amplitude=1.0, frequencies=...)`	Gaussian line shape
`voigt_line(center, sigma, gamma, amplitude=1.0, frequencies=...)`	Voigt profile (convolution of Gaussian and Lorentzian)

gwexpy.noise.wave

Functions for generating time-series waveforms. All functions return TimeSeries.

Noise Generators

Function	Description
`gaussian(duration, sample_rate, std=1.0, mean=0.0, ...)`	Gaussian (normal) white noise
`uniform(duration, sample_rate, low=-1.0, high=1.0, ...)`	Uniform white noise
`colored(duration, sample_rate, exponent, amplitude=1.0, ...)`	Power-law colored noise
`white_noise(duration, sample_rate, amplitude=1.0, ...)`	White noise (exponent=0)
`pink_noise(duration, sample_rate, amplitude=1.0, ...)`	Pink noise (1/f^0.5 spectrum)
`red_noise(duration, sample_rate, amplitude=1.0, ...)`	Red/Brownian noise (1/f spectrum)
`from_asd(asd, duration, sample_rate, ...)`	Generate colored noise from ASD

Periodic Waveforms

Function	Description
`sine(duration, sample_rate, frequency, ...)`	Sine wave
`square(duration, sample_rate, frequency, duty=0.5, ...)`	Square wave
`sawtooth(duration, sample_rate, frequency, width=1.0, ...)`	Sawtooth wave
`triangle(duration, sample_rate, frequency, ...)`	Triangle wave
`chirp(duration, sample_rate, f0, f1, method='linear', ...)`	Swept-frequency cosine (chirp)

Transient Signals

Function	Description
`step(duration, sample_rate, t_step=0.0, amplitude=1.0, ...)`	Step (Heaviside) function
`impulse(duration, sample_rate, t_impulse=0.0, amplitude=1.0, ...)`	Impulse signal
`exponential(duration, sample_rate, tau, decay=True, ...)`	Exponential (decay/growth)

Examples

from gwexpy.noise.wave import sine, gaussian, chirp, from_asd
from gwexpy.noise.asd import from_pygwinc, schumann_resonance

# Sine wave
wave = sine(duration=1.0, sample_rate=1024, frequency=10.0)

# Gaussian noise
noise = gaussian(duration=1.0, sample_rate=1024, std=0.1)

# Chirp (swept sine)
sweep = chirp(duration=1.0, sample_rate=1024, f0=10, f1=100)

# Detector strain ASD from pyGWINC
asd = from_pygwinc('aLIGO', quantity='strain', fmin=4.0, fmax=1024.0, df=0.01)
noise = from_asd(asd, duration=128, sample_rate=2048, t0=0)

# Schumann resonance model
sch_asd = schumann_resonance(harmonics=5)