pathsim.blocks.noise module

class pathsim.blocks.noise.WhiteNoise(spectral_density=1, sampling_rate=None)

Bases: Block

White noise source with uniform spectral density. Samples from distribution with ‘sampling_rate’ and holds noise values constant for time bins.

If no ‘sampling_rate’ (None) is specified, every simulation timestep gets a new noise value. This is the default setting.

Parameters:

• spectral_density (float) – noise spectral density

• noise (float) – internal noise value

• sampling_rate (float, None) – frequency with which the noise is sampled

sigma

sqrt of spectral density -> signal amplitude

Type:

float

n_samples

internal sample counter

Type:

int

reset()

Reset the blocks inputs and outputs and also its internal solver, if the block has a solver instance.

sample(t)

Sample from a normal distribution after successful timestep

Parameters:

t (float) – evaluation time for sampling

update(t)

update system equation for fixed point loop, here just setting the outputs

Note

no direct passthrough, so the ‘update’ method is optimized for this case

Parameters:

t (float) – evaluation time

class pathsim.blocks.noise.PinkNoise(spectral_density=1, num_octaves=16, sampling_rate=None)

Bases: Block

Pink noise (1/f) source using the Voss-McCartney algorithm.

Samples from distribution with ‘sampling_rate’ and generates noise with a power spectral density inversely proportional to frequency.

Parameters:

• spectral_density (float) – Desired noise spectral density

• num_octaves (int) – Number of octaves (levels of randomness)

• sampling_rate (float, None) – Frequency with which the noise is sampled

sigma

sqrt of spectral density normalized to number of octaves

Type:

float

n_samples

internal sample counter

Type:

int

noise

internal noise value

Type:

float

octaves_values

internal random numbers for octaves in the Voss-McCartney algorithm

Type:

array[float]

reset()

Reset the blocks inputs and outputs and also its internal solver, if the block has a solver instance.

sample(t)

Generate a new pink noise sample at ‘t’ using the Voss-McCartney algorithm.

Parameters:

t (float) – evaluation time for sampling

update(t)

update system equation for fixed point loop, here just setting the outputs

Note

no direct passthrough, so the ‘update’ method is optimized for this case

Parameters:

t (float) – evaluation time