sigpyproc.header

sigpyproc.header#

Header class for handling observation metadata.

This module contains the Header class for handling observation metadata.

Classes

Header

Container object to handle observation metadata.

class sigpyproc.header.Header(*, filename, data_type, nchans, foff, fch1, nbits, tsamp, tstart, nsamples, nifs=attr_dict['nifs'].default, coord=attr_dict['coord'].default, azimuth=attr_dict['azimuth'].default, zenith=attr_dict['zenith'].default, telescope=attr_dict['telescope'].default, backend=attr_dict['backend'].default, source=attr_dict['source'].default, frame=attr_dict['frame'].default, ibeam=attr_dict['ibeam'].default, nbeams=attr_dict['nbeams'].default, dm=attr_dict['dm'].default, period=attr_dict['period'].default, accel=attr_dict['accel'].default, signed=attr_dict['signed'].default, rawdatafile=attr_dict['rawdatafile'].default, stream_info=attr_dict['stream_info'].default)[source]#

Bases: object

Container object to handle observation metadata.

Parameters:

filenamestr: Name of the header file.
data_typestr: Type of data (filterbank, time series).
nchansint: Number of frequency channels.
fofffloat: Frequency channel width in MHz.
fch1float: Central frequency of the first channel in MHz.
nbitsint: Number of bits per sample.
tsampfloat: Sampling time in seconds.
tstartfloat: Start time of the observation in MJD.
nsamplesint: Number of time samples in the observation.
nifsint, optional: Number of polarizations, by default 1.
coordSkyCoord, optional: Source sky coordinates, by default (0, 0).
azimuthAngle, optional: Telescope Azimuth angle, by default 0.
zenithAngle, optional: Telescope Zenith angle, by default 0.
telescopestr, optional: Telescope name, by default “Fake”.
backendstr, optional: Telescope backend name, by default “FAKE”.
sourcestr, optional: Source name, by default “Fake”.
framestr, optional: Reference frame, by default “topocentric”.
ibeamint, optional: Telescope beam number, by default 0.
nbeamsint, optional: Number of beams, by default 0.
dmfloat, optional: Reference Dispersion Measure, by default 0.
periodfloat, optional: Rotation period of the source, by default 0.
accelfloat, optional: Binary acceleration of the source, by default 0.
signedbool, optional: Whether the data is signed, by default False.
rawdatafilestr, optional: Name of the original raw data file, by default “”.
stream_infoStreamInfo, optional: File stream information, by default sigproc.StreamInfo().

Attributes:

basename: Basename of header filename.
extension: Extension of header filename.
telescope_id: Telescope id in Sigproc format.
machine_id: Machine id in Sigproc format.
bandwidth: Frequency bandwidth in MHz.
ftop: Edge frequency of the top frequency channel.
fbottom: Edge frequency of the bottom frequency channel.
fcenter: Central frequency of the whole band.
chan_freqs: Center frequency of each channel.
fmax: Center frequency of the maximum frequency channel.
fmin: Center frequency of the minimum frequency channel.
dtype: Type of the data in file.
tobs: Total time of the observation.
ra: Right Ascension in string representation.
dec: Declination in string representation.
obs_date: Observation date and time in ISO format.

Methods

`dedispersed_header`(dm)	Get a dedispersed version of the current header.
`from_fbh5`(filename)	Parse the metadata from a filterbank HDF5 file.
`from_inffile`(filename)	Parse the metadata from a presto `.inf` file.
`from_pfits`(filename)	Parse the metadata from a PSRFITS file.
`from_sigproc`(filenames, *[, check_contiguity])	Parse the metadata from Sigproc-style files.
`get_dmdelays`(dm[, ref_freq, in_samples])	Get ISM dispersion delays for given DM value(s).
`get_dmsmearing`(dm, *[, in_samples])	Get ISM smearing for given DM value(s).
`make_inf`([outfile])	Make a presto format `.inf` file.
`mjd_after_nsamps`(nsamps)	Compute the MJD after nsamps have elapsed.
`new_header`([update_dict])	Get a new updated instance of `Header`.
`prep_outfile`(filename, *[, updates, nbits, ...])	Prepare a file with Sigproc format data.
`to_dict`(*[, with_properties])	Get a dictionary of all attributes.
`to_sigproc`()	Get header dictionary in Sigproc format.
`to_string`()	Get a string representation of the header.

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#

stream_info#

property basename#

Basename of header filename.

Returns:

str: Header filename without extension.

property extension#

Extension of header filename.

Returns:

str: Header filename extension.

property telescope_id#

Telescope id in Sigproc format.

Returns:

int: Sigproc telescope id.

property machine_id#

Machine id in Sigproc format.

Returns:

int: Sigproc machine id.

property bandwidth#

Frequency bandwidth in MHz.

Returns:

float: Bandwidth in MHz.

property ftop#

Edge frequency of the top frequency channel.

Returns:

float: Edge frequency at the top of the band.

property fbottom#

Edge frequency of the bottom frequency channel.

Returns:

float: Edge frequency at the bottom of the band.

property fcenter#

Central frequency of the whole band.

Returns:

float: Central frequency.

property chan_freqs#

Center frequency of each channel.

Returns:

ndarray: Channel center frequencies.

property fmax#

Center frequency of the maximum frequency channel.

Returns:

float: Maximum frequency in the band.

property fmin#

Center frequency of the minimum frequency channel.

Returns:

float: Minimum frequency in the band.

property dtype#

Type of the data in file.

Returns:

dtype: Data type.

property tobs#

Total time of the observation.

Returns:

float: Observation time.

property ra#

Right Ascension in string representation.

Returns:

str: Right Ascension.

property dec#

Declination in string representation.

Returns:

str: Declination.

property obs_time#

Observation time in Astropy Time format.

Returns:

Time: Observation time in Astropy Time format.

property obs_date#

Observation date and time in ISO format.

Returns:

str: Observation date and time.

mjd_after_nsamps(nsamps)[source]#

Compute the MJD after nsamps have elapsed.

Parameters:

nsampsint: Number of samples elapsed since start of observation.

Returns:

float: Modified Julian Date.

get_dmdelays(dm, ref_freq='fch1', *, in_samples=True)[source]#

Get ISM dispersion delays for given DM value(s).

Parameters:

dmfloat | np.ndarray: Dispersion measure(s) to calculate delays for.
ref_freqstr | float, optional: Reference frequency to calculate delays from, by default “fch1”. Accepted inputs are “fmax”, “fmin”, “fcenter”, “fch1” or a number in MHz.
in_samplesbool, optional: Flag to return delays as numbers of samples, by default True.

Returns:

ndarray

Dispersion delays at middle of each channel with respect to ref_freq.

If dm is a scalar, returns a 1D array of delays. If dm is an array, returns a 2D array with shape (len(dm), len(freqs)).

get_dmsmearing(dm, *, in_samples=True)[source]#

Get ISM smearing for given DM value(s).

Parameters:

dmfloat | np.ndarray: Dispersion measure(s) to calculate smearing for.
in_samplesbool, optional: Flag to return smearing as numbers of samples, by default True.

Returns:

ndarray

DM smearing in the frequency channels due to finite bandwidth.

If dm is a scalar, returns a 1D array of smearing. If dm is an array, returns a 2D array with shape (len(dm), len(freqs)).

new_header(update_dict=None)[source]#

Get a new updated instance of Header.

This is the preferred way to update the header.

Parameters:

update_dictdict, optional: Values to overide existing header values, by default None.

Returns:

Header: A new instance of the header with updated values.

dedispersed_header(dm)[source]#

Get a dedispersed version of the current header.

Parameters:

dmfloat: Dispersion measure to dedisperse to.

Returns:

Header: A new header with updated DM value.

to_dict(*, with_properties=True)[source]#

Get a dictionary of all attributes.

Parameters:

with_propertiesbool, optional: Whether to include properties in the output, by default True.

Returns:

dict[str, Any]: All attributes of the header.

to_sigproc()[source]#

Get header dictionary in Sigproc format.

Returns:

dict: Sigproc formatted header values.

to_string()[source]#

Get a string representation of the header.

Returns:

str: A string representation of the header.

prep_outfile(filename, *, updates=None, nbits=None, rescale=False)[source]#

Prepare a file with Sigproc format data.

This is the preferred way to write a new Sigproc file.

Parameters:

filenamestr: Name of new file.
updatesdict, optional: Values to overide existing header values, by default None.
nbitsint, optional: Number of bits per output sample, by default None.
rescalebool, optional: Whether to rescale the data using the nbit-dependent values, by default True.

Returns:

FileWriter: A file writer object to write data to.

make_inf(outfile=None)[source]#

Make a presto format .inf file.

Parameters:

outfilestr, optional: Name of the output file, by default None.

Returns:

str: A string representation of .inf data.

classmethod from_inffile(filename)[source]#

Parse the metadata from a presto .inf file.

Parameters:

filenamestr | Path: Name of the .inf file containing the header.

Returns:

Header: Observational metadata.

classmethod from_sigproc(filenames, *, check_contiguity=True)[source]#

Parse the metadata from Sigproc-style files.

Parameters:

filenamesstr | Path | Sequence[str | Path]: Sigproc filterbank files containing the header.
check_contiguitybool, optional: Check if the files are contiguous, by default True.

Returns:

Header: Observational metadata.

classmethod from_pfits(filename)[source]#

Parse the metadata from a PSRFITS file.

Parameters:

filenamestr: Name of the PSRFITS file containing the header.

Returns:

Header: Observational metadata.

classmethod from_fbh5(filename)[source]#

Parse the metadata from a filterbank HDF5 file.

Parameters:

filenamestr: Name of the HDF5 file containing the header.

Returns:

Header: Observational metadata.

sigpyproc.header

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sigpyproc.header#