ezmsg.sigproc.downsample#

Integer downsampling by selecting every Nth sample along an axis.

Functions

downsample(axis='time', target_rate=None, factor=None)[source]#

Parameters:

axis (str)
target_rate (float | None)
factor (int | None)

Return type:

DownsampleTransformer

Classes

class Downsample(*args, settings=None, **kwargs)[source]#

Bases: BaseTransformerUnit[DownsampleSettings, AxisArray, AxisArray, DownsampleTransformer]

Parameters:: settings (Settings | None)

SETTINGS#: alias of DownsampleSettings

async on_signal(message)[source]#

Skip the publish when no samples accumulated.

At factor > 1 most input chunks span less than one downsample period, so DownsampleTransformer._process returns a payload with a zero-length axis. Suppressing the broadcast in that case avoids shipping an empty AxisArray across SHM/socket every input chunk.

Parameters:: message (AxisArray)
Return type:: AsyncGenerator

class DownsampleSettings(axis='time', target_rate=None, factor=None)[source]#

Bases: Settings

Settings for Downsample node.

Parameters:

axis (str)
target_rate (float | None)
factor (int | None)

axis: str = 'time'#: The name of the axis along which to downsample.

target_rate: float | None = None#: Desired rate after downsampling. The actual rate will be the nearest integer factor of the input rate that is the same or higher than the target rate.

factor: int | None = None#: Explicitly specify downsample factor. If specified, target_rate is ignored.

__init__(axis='time', target_rate=None, factor=None)#

Parameters:

axis (str)
target_rate (float | None)
factor (int | None)

Return type:

None

class DownsampleState[source]#

Bases: object

q: int = 0#: The integer downsampling factor. It will be determined based on the target rate.

s_idx: int = 0#: Index of the next msg’s first sample into the virtual rotating ds_factor counter.

class DownsampleTransformer(*args, **kwargs)[source]#

Bases: BaseStatefulTransformer[DownsampleSettings, AxisArray, AxisArray, DownsampleState]

Downsampled data simply comprise every factor`th sample. This should only be used following appropriate lowpass filtering. If your pipeline does not already have lowpass filtering then consider using the :obj:`Decimate collection instead.