Glossary
- channel
- 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.
- component
- 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.
- payload
- The data within a 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 complete sample, or a
stream thereof. For VDIF, each thread is carried by a separate
(set of) data frame(s).