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EPN Data Format

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  1.   1.  About
  2.   2.  Format Description
    1.   2.1  Overview
  3.   3.  EPN 6.30 Specification
    1.   3.1  Main Header definition
    2.   3.2  Detailed Description of Header Elements

1.  About

The EPN data format is a portable way to transfer folded profiles and single pulses. It is encoded in plain text, with profiles stored as hexadecimal numbers. This means that the file can be viewed and editied with a text editor. Since, however, there are no seperators between any of the header elements in the file, it can be difficult to parse the file manualy.

The EPN format has undergone a number of changes to the data structure since it’s introduction in 1998, however the core elements remain the same.

2.  Format Description

2.1  Overview

The EPN Data Format is encoded in 8-bit ASCII characters. The format is designed so that it splits across 80 byte ‘lines’, although the format does not include any line feed or carrage return characters. In this document, line is defined as an 80 character segment of the data.

An EPN data block is split into a 6-line (480 byte) main header, followed by one or more data streams, which themselves consist of a 2-line (160 byte) stream header and a variable length hex encoded profile.

An EPN file may contain one or more EPN data blocks.

3.  EPN 6.30 Specification

The latest released version of the EPN data format is EPN 6.30.

3.1  Main Header definition

Line 1
NameSizeFormatUnitsDescription
EPN Version9String The EPN version identifier. Currently ‘EPN 6.30 ‘
Counter7Integer The number of lines in this EPN data block
History67String A freeform text string to describe the data
Line 2
NameSizeFormat Description
JName14String Pulsar JName
CName14String Pulsar ‘common name’. Usualy BName
PBar17DecimalsBarycentric Period of the Pulsar at epoch
DM9Decimalcm^{-3}pcDispersion measure of Pulsar
RM11Decimalrad m^2Rotation Measure of Pulsar
CatRef7String Catalogue reference for parameters
BibRef9String Bibliographic reference for data
Line 3
Line 4
Line 5
Line 6
Line 6 is special, it contains no data but consists of 80 ‘-‘ characters.

3.2  Detailed Description of Header Elements

Counter

At one time counter specified the number of streams in a file, however because of the variable length of streams and the fact that more than one EPN Data Block can be allowed in a file, this was changed to the number of 80-character lines in the data block. This allows for skipping through data blocks without parsing them entirely.

Data Formats
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Page last modified on July 31, 2007, at 04:21 AM