.. _glossary: .. include:: glossary_substitutions.rst ******** Glossary ******** .. glossary:: channel A single component of the :term:`complete sample`, or a :term:`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 :term:`sample shape`. component One individual :term:`thread` and :term:`channel`, or one polarization and channel, etc. Component samples each occupy one element in decoded data arrays. A component sample is composed of one :term:`elementary sample` if it is real, and two if it is complex. data frame A block of time-sampled data, or :term:`payload`, accompanied by a :term:`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 :term:`component` of a :term:`complete sample`. header Metadata accompanying a :term:`data frame`. payload The data within a :term:`data frame`. sample 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. squeezing The removal of any dimensions of length unity from decoded data. stream Timeseries of |samples|; may refer to all of, or a subsection of, the dataset. subset A subset of a complete sample, in particular one defined by the user for selective decoding. thread A collection of |channels| from the :term:`complete sample`, or a :term:`stream` thereof. For VDIF, each thread is carried by a separate (set of) :term:`data frame(s)`.