sigpyproc.header

sigpyproc.header

class sigpyproc.header.Header(*, filename, data_type, nchans, foff, fch1, nbits, tsamp, tstart, nsamples, nifs=1, coord=<SkyCoord (ICRS): (ra, dec) in deg     (0., 0.)>, azimuth=<Angle 0. deg>, zenith=<Angle 0. deg>, telescope='Fake', backend='Fake', source='Fake', frame='topocentric', ibeam=0, nbeams=0, dm=0, period=0, accel=0, signed=False, rawdatafile=None, hdrlens=NOTHING, datalens=NOTHING, filenames=NOTHING, nsamples_files=NOTHING, tstart_files=NOTHING)

Bases: object

Container object to handle observation metadata.

Parameters

  • filename (str) – filename

  • data_type (str) – data type

  • nchans (int) – Number of channels

  • foff (float) – Channel width in MHz

  • fch1 (float) – Central frequency of the first channel in MHz

  • nbits (int) – Number of bits of sample

  • tsamp (float) – Sampling time

  • tstart (float) – Start MJD

  • nsamples (int) – Number of samples

  • nifs (int) – Number of polarizations

  • coord (SkyCoord) – Sky coordinate

  • azimuth (Angle) – Telescope Azimuth

  • zenith (Angle) – Telescope Zenith angle

  • telescope (str) – Telescope name

  • backend (str) – Backend name

  • source (str) – Source name

  • frame (str) – Frame (Topocentric)

  • ibeam (int) – Beam no

  • nbeams (int) – Total beams

  • dm (float) – Reference DM

  • period (float) – Period

  • accel (float) – Acceleration

  • signed (bool) – if the data is signed

  • rawdatafile (str or None) – Original file name

  • hdrlens (list of int) – List of header length of files

  • datalens (list of int) – List of data length of files

  • filenames (list of str) – List of filenames

  • nsamples_files (list of int) – List of samples in each file

  • tstart_files (list of float) – List of start MJD in each file

filename
data_type
nchans
foff
fch1
nbits
tsamp
tstart
nsamples
nifs
coord
azimuth
zenith
telescope
backend
source
frame
ibeam
nbeams
dm
period
accel
signed
rawdatafile
hdrlens
datalens
filenames
nsamples_files
tstart_files
property basename

Basename of header filename (str, read-only).

property extension

Extension of header filename (str, read-only).

property telescope_id

Telescope id (int, read-only).

property machine_id

Machine id (str, read-only).

property bandwidth

Bandwidth in MHz (float, read-only).

property ftop

Frequency (boundary) of the top channel (float, read-only).

property fbottom

Frequency (boundary) of the bottom channel (float, read-only).

property fcenter

Central frequency of the whole band (float, read-only).

property chan_freqs

Frequency (center) of each channel(ndarray, read-only).

property dtype

Type of the data (np.dtype, read-only).

property tobs

Total time of the observation (float, read-only).

property ra

Right Ascension (str, read-only).

property dec

Declination (str, read-only).

property obs_date

Observation date and time (str, read-only).

mjd_after_nsamps(nsamps)

Find the Modified Julian Date after nsamps have elapsed.

Parameters

nsamps (int) – number of samples elapsed since start of observation.

Returns

Modified Julian Date

Return type

float

get_dmdelays(dm, in_samples=True)

For a given dispersion measure get the dispersive ISM delay for middle of each frequency channel.

Parameters

  • dm (float) – dispersion measure to calculate delays for

  • in_samples (bool, optional) – flag to return delays as numbers of samples, by default True

Returns

delays for middle of each channel (highest frequency first)

Return type

ndarray

new_header(update_dict=None)

Get a new instance of Header.

Parameters

update_dict (dict, optional) – values to overide existing header values, by default None

Returns

new header information

Return type

Header

dedispersed_header(dm)

Get a dedispersed version of the current header.

Parameters

dm (float) – dispersion measure we are dedispersing to

Returns

A dedispersed version of the header

Return type

Header

to_dict(with_properties=True)

Get a dict of all attributes including property attributes.

Returns

attributes

Return type

dict

to_sigproc(as_dict=False)

Get sigproc format header binary header.

Returns

header in binary format

Return type

str

prep_outfile(filename, update_dict=None, nbits=None, quantize=False, interval_seconds=10, constant_offset_scale=False, **kwargs)

Prepare a file to have sigproc format data written to it.

Parameters

  • filename (str) – name of new file

  • update_dict (dict, optional) – values to overide existing header values, by default None

  • nbits (int, optional) – the bitsize of data points that will written to this file (1,2,4,8,32), by default None

Returns

a prepared file

Return type

FileWriter

make_inf(outfile=None)

Make a presto format .inf file.

Parameters

outfile (str, optional) – a filename to write to, by default None

Returns

if outfile is unspecified .inf data is returned as string

Return type

str

classmethod from_inffile(filename)

Parse the metadata from a presto .inf file.

Parameters

filename (str) – the name of the .inf file containing the header

Returns

observational metadata

Return type

Header

classmethod from_sigproc(filenames, check_contiguity=True)

Parse the metadata from Sigproc-style file/sequential files.

Parameters

filenames (list) – sigproc filterbank files containing the header

Returns

observational metadata

Return type

Header

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