sigpyproc.io.sigproc

Sigproc-style header parsing and editing.

This module contains functions for parsing and editing Sigproc-style headers.

Classes

FileInfo	Class to handle individual file information.
HeaderField	Class to handle sigproc header schema fields.
StreamInfo	Class to handle stream information as a list of FileInfo objects.

Functions

edit_header	Edit a sigproc style header directly in place for the given file.
encode_header	Encode sigproc header dict in binary format.
encode_key	Encode single SIGPROC header key to a bytes string.
match_header	Match header keywords between two parsed sigproc headers.
parse_header	Parse the metadata from a single Sigproc-style filterbank file.
parse_header_multi	Parse the metadata from Sigproc-style file/sequential files.
parse_radec	Parse Sigproc format RADEC float as Astropy SkyCoord.

Module Attributes

SIGPROC_SCHEMA	Header keys recognised by the sigproc package.
telescope_ids	Telescope IDs recognised by the sigproc package.
machine_ids	Machine IDs recognised by the sigproc package.

sigpyproc.io.sigproc.SIGPROC_SCHEMA

Header keys recognised by the sigproc package.

SIGPROC Header Schema

Key	Binary format	Description
az_start	<d (8 bytes)	Telescope azimuth at start of scan (degrees)
barycentric	<I (4 bytes)	Whether the data are barycentric (1) or otherwise (0)
data_type	<I (4 bytes)	Numeric data type identifier
fch1	<d (8 bytes)	Centre frequency (MHz) of first filterbank channel
foff	<d (8 bytes)	Filterbank channel bandwidth (MHz)
ibeam	<I (4 bytes)	Beam number of the observation
machine_id	<I (4 bytes)	Numeric machine identifier
nbeams	<I (4 bytes)	Number of beams in the observation
nbits	<I (4 bytes)	Number of bits per time sample
nchans	<I (4 bytes)	Number of frequency channels
nifs	<I (4 bytes)	Number of seperate IF channels
nsamples	<I (4 bytes)	Number of time samples in the data file (rarely used)
period	<d (8 bytes)	Pulsar folding period (s)
pulsarcentric	<I (4 bytes)	Whether the data are pulsarcentric (1) or otherwise (0)
rawdatafile	string	Name of the original data file
refdm	<d (8 bytes)	Reference Dispersion Measure (pc/cm^3)
signed	b (1 bytes)	Sign convention of 8-bit data samples
source_name	string	Name of the observed source
src_dej	<d (8 bytes)	Declination of source (DDMMSS.S)
src_raj	<d (8 bytes)	Right ascension (J2000) of source (HHMMSS.S)
telescope_id	<I (4 bytes)	Numeric telescope identifier
tsamp	<d (8 bytes)	Time interval between samples (s)
tstart	<d (8 bytes)	Time stamp (MJD) of first sample
za_start	<d (8 bytes)	Telescope zenith angle at start of scan (degrees)

sigpyproc.io.sigproc.telescope_ids

Telescope IDs recognised by the sigproc package.

Radio Telescope IDs

Radio Telescope	SIGPROC ID
Fake	0
Arecibo	1
Ooty	2
Nancay	3
Parkes	4
Jodrell	5
GBT	6
GMRT	7
Effelsberg	8
Effelsberg LOFAR	9
SRT	10
LOFAR	11
VLA	12
CHIME	20
MWA	30
NC	40
NGNC	41
MeerKAT	64

sigpyproc.io.sigproc.machine_ids

Machine IDs recognised by the sigproc package.

Telescope Backend IDs

Radio Telescope Backend	SIGPROC ID
FAKE	0
PSPM	1
WAPP	2
AOFTM	3
BPP	4
OOTY	5
SCAMP	6
GMRTFB	7
PULSAR2000	8
PARSPEC	9
BPSR	10
COBALT	11
GMRTNEW	14
CHIME	20
MWA-VCS	30
MWAX-VCS	31
MWAX-RTB	32
ADU	40
iTPM	41

class sigpyproc.io.sigproc.FileInfo(*, filename, hdrlen, datalen, nsamples, tstart, tsamp)

Bases: object

Class to handle individual file information.

Attributes:

datalen

filename

hdrlen

nsamples

tend

Get the end time of the file.

tsamp

tstart

Methods

from_dict

filename

hdrlen

datalen

nsamples

tstart

tsamp

property tend

Get the end time of the file.

classmethod from_dict(info)

class sigpyproc.io.sigproc.HeaderField(*, fmt, doc)

Bases: object

Class to handle sigproc header schema fields.

Attributes:

fmtstruct.Struct or None

Format struct; None for string fields.

docstr

Human-readable description of the field.

fmt

doc

class sigpyproc.io.sigproc.StreamInfo(entries=<factory>)

Bases: object

Class to handle stream information as a list of FileInfo objects.

Attributes:

cumsum_datalens

Get the cumulative sum of datalen for all entries.

entries

time_gaps

Get the time gaps between files.

Methods

add_entry(finfo)	Add a FileInfo entry to the StreamInfo object.
check_contiguity()	Check if the files in the stream are contiguous/sequential.
get_combined(key)	Get the combined value of a key for all entries.
get_info_list(key)	Get list of values for a given key for all entries.

entries

property cumsum_datalens

Get the cumulative sum of datalen for all entries.

property time_gaps

Get the time gaps between files.

add_entry(finfo)

Add a FileInfo entry to the StreamInfo object.

get_combined(key)

Get the combined value of a key for all entries.

get_info_list(key)

Get list of values for a given key for all entries.

check_contiguity()

Check if the files in the stream are contiguous/sequential.

sigpyproc.io.sigproc.edit_header(filename, key, value)

Edit a sigproc style header directly in place for the given file.

Parameters:

filenamestr | Path

Name of the sigproc file to modify header.

keystr

Name of parameter to change (must be a valid sigproc key)

valueint or float or str

new value to enter into header

Raises:

ValueError

if the new header to be written to file is longer or shorter than the header that was previously in the file.

Notes

It is up to the user to be responsible with this function, as it will directly change the file on which it is being operated.

sigpyproc.io.sigproc.encode_header(header, *, allow_nsamples_overwrite=False)

Encode sigproc header dict in binary format.

Returns:

bytes

header in binary format

sigpyproc.io.sigproc.encode_key(key, value=None)

Encode single SIGPROC header key to a bytes string.

Parameters:

keystr

header key

valueint or float or str, optional

value of the header key, by default None

Returns:

bytes

bytes encoded string

sigpyproc.io.sigproc.match_header(header1, header2)

Match header keywords between two parsed sigproc headers.

Parameters:

header1dict

parsed header from file 1.

header2dict

parsed header from file 2.

Raises:

ValueError

if key values do not match.

sigpyproc.io.sigproc.parse_header(filename)

Parse the metadata from a single Sigproc-style filterbank file.

Parameters:

filenamestr | Path

Path to the sigproc filterbank file.

Returns:

dict[str, float | int | str]

Observational metadata, plus computed keys.

Raises:

OSError

If the file header is not in sigproc format, is empty, or is truncated mid-header.

ValueError

If required keys (nbits, nchans) are missing or nsamples is zero.

sigpyproc.io.sigproc.parse_header_multi(filenames, *, check_contiguity=True)

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

Parameters:

filenamesstr | Path | Sequence[str | Path]

sigproc filterbank files containing the header

Returns:

tuple[dict[str, float | int | str], StreamInfo]

observational metadata and stream info

sigpyproc.io.sigproc.parse_radec(src_raj, src_dej)

Parse Sigproc format RADEC float as Astropy SkyCoord.

Parameters:

src_rajfloat

Sigproc style HHMMSS.SSSS right ascension

src_dejfloat

Sigproc style DDMMSS.SSSS declination

Returns:

SkyCoord

Astropy coordinate class