EPN Data Format
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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 | ||||
|---|---|---|---|---|
| Name | Size | Format | Units | Description |
| EPN Version | 9 | String | The EPN version identifier. Currently ‘EPN 6.30 ‘ | |
| Counter | 7 | Integer | The number of lines in this EPN data block | |
| History | 67 | String | A freeform text string to describe the data | |
| Line 2 | ||||
| Name | Size | Format | Description | |
| JName | 14 | String | Pulsar JName | |
| CName | 14 | String | Pulsar ‘common name’. Usualy BName | |
| PBar | 17 | Decimal | s | Barycentric Period of the Pulsar at epoch |
| DM | 9 | Decimal |  | Dispersion measure of Pulsar |
| RM | 11 | Decimal |  | Rotation Measure of Pulsar |
| CatRef | 7 | String | Catalogue reference for parameters | |
| BibRef | 9 | String | 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