`AngleTracker`#

class acoular.tprocess.AngleTracker(*args, **kwargs)

Bases: MaskedTimeOut

Compute the rotational angle and RPM per sample from a trigger signal in the time domain.

Deprecated since version :class:`AngleTracker`: is deprecated and will be removed in version 27.01.

This class retrieves samples from the specified trigger signal and interpolates angular position and rotational speed. The results are stored in the properties angle and rpm.

The algorithm assumes a periodic trigger signal marking rotational events (e.g., a tachometer pulse or an encoder signal) and interpolates the angle and RPM using cubic splines. It is capable of handling different rotational directions and numbers of triggers per revolution.

trigger: Trigger data source, expected to be an instance of Trigger.

digest: A unique identifier for the tracker, based on its properties. (read-only)

trigger_per_revo: Number of trigger signals per revolution. This allows tracking scenarios where multiple trigger pulses occur per rotation. Default is 1, meaning a single trigger per revolution.

rot_direction

Rotation direction flag:

1: counter-clockwise rotation.
-1: clockwise rotation.

Default is -1.

interp_points: Number of points used for spline interpolation. Default is 4.

start_angle: Initial rotation angle (in radians) corresponding to the first trigger event. This allows defining a custom starting reference angle. Default is 0.

rpm: Revolutions per minute (RPM) computed for each sample. It is based on the trigger data. (read-only)

average_rpm: Average revolutions per minute over the entire dataset. It is computed based on the trigger intervals. (read-only)

angle: Computed rotation angle (in radians) for each sample. It is interpolated from the trigger data. (read-only)

result(num)

Generate blocks of processed data, selecting only valid samples and channels.

This method fetches data from the source object, applies the defined start and stop constraints on time samples, and filters out invalid_channels. The data is then yielded in block-wise fashion to facilitate efficient streaming.

Parameters:

numint: Number of samples per block.

Yields:

numpy.ndarray: An array of shape (num, MaskedTimeOut.num_channels), contatining blocks of a filtered time-domain signal. The last block may contain fewer samples if the total number of samples is not a multiple of num. MaskedTimeOut.num_channels is not inherited directly and may be smaller than the source’s number of channels.

Raises:

OSError: If no valid samples are available within the defined start and stop range. This can occur if start is greater than or equal to stop or if the source is not containing any valid samples in the given range.

source: The input data source. It must be an instance of a SamplesGenerator-derived class. This object provides the raw time-domain signals that will be filtered based on the start, stop, and invalid_channels attributes.

start: The index of the first valid sample. Default is 0.

stop: The index of the last valid sample (exclusive). If set to None, the selection continues until the end of the available data.

invalid_channels: List of channel indices to be excluded from processing.

channels: A mask or index array representing valid channels. (automatically updated)

num_channels_total: Total number of input channels, including invalid channels, as given by source. (read-only).

num_samples_total: Total number of input channels, including invalid channels. (read-only).

num_channels: Number of valid input channels after excluding invalid_channels. (read-only)

num_samples: Number of valid time-domain samples, based on start and stop indices. (read-only)

basename: The name of the cache file (without extension). It serves as an internal reference for data caching and tracking processed files. (automatically generated)

sample_freq: Sampling frequency of output signal, as given by source.

AngleTracker#

`AngleTracker`#