neurodsp.sim.utils.rotate_spectrum¶

neurodsp.sim.utils.rotate_spectrum(freqs, spectrum, delta_exponent, f_rotation=1)[source]¶

Rotate the power law exponent of a power spectrum.

Parameters

freqs1d array: Frequency axis of input spectrum, in Hz.
spectrum1d array: Power spectrum to be rotated.
delta_exponentfloat: Change in power law exponent to be applied. Positive is clockwise rotation (steepen), negative is counter clockwise rotation (flatten).
f_rotationfloat, optional, default: 1: Frequency, in Hz, to rotate the spectrum around, where power is unchanged by the rotation. This only matters if not further normalizing signal variance.

Returns

rotated_spectrum1d array: Rotated spectrum.

Notes

The input power spectrum is multiplied with a mask that applies the specified exponent change.

Examples

Rotate a power spectrum, calculated on simulated data:

>>> from neurodsp.sim import sim_combined
>>> from neurodsp.spectral import compute_spectrum
>>> sig = sim_combined(n_seconds=10, fs=500,
...                    components={'sim_powerlaw': {}, 'sim_oscillation' : {'freq': 10}})
>>> freqs, spectrum = compute_spectrum(sig, fs=500)
>>> rotated_spectrum = rotate_spectrum(freqs, spectrum, -1)