A single component of the complete sample, or a stream thereof. They typically represent one frequency sub-band, the output from a single antenna, or (for channelized data) one spectral or Fourier channel, ie. one part of a Fourier spectrum.

complete sample

Set of all component samples - ie. from all threads, polarizations, channels, etc. - for one point in time. Its dimensions are given by the sample shape.


One individual thread and channel, or one polarization and channel, etc. Component samples each occupy one element in decoded data arrays. A component sample is composed of one elementary sample if it is real, and two if it is complex.

data frame

A block of time-sampled data, or payload, accompanied by a header. “Frame” for short.

data frameset

In the VDIF format, the set of all data frames representing the same segment of time. Each data frame consists of sets of channels from different threads.

elementary sample

The smallest subdivision of a complete sample, i.e. the real / imaginary part of one component of a complete sample.


Metadata accompanying a data frame.


The data within a data frame.


Data from one point in time. Complete samples contain samples from all components, while elementary samples are one part of one component.

sample rate

Rate of complete samples.

sample shape

The lengths of the dimensions of the complete sample.


The removal of any dimensions of length unity from decoded data.


Timeseries of samples; may refer to all of, or a subsection of, the dataset.


A subset of a complete sample, in particular one defined by the user for selective decoding.


A collection of channels from the complete sample, or a stream thereof. For VDIF, each thread is carried by a separate (set of) data frame(s).