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Welcome to the SigMF project! TheSigMF specifications can be viewed here ordownloaded as a PDF. Below we discuss why and how you might use SigMF in your projects.

Sharing sets of recorded signal data is an important part of science andengineering. It enables multiple parties to collaborate, is often a necessarypart of reproducing scientific results (a requirement of scientific rigor), andenables sharing data with those who do not have direct access to the equipmentrequired to capture it.

Unfortunately, these datasets have historically not been very portable, andthere is not an agreed upon method of sharing metadata descriptions of therecorded data itself. This is the problem that SigMF solves.

By providing a standard way to describe data recordings, SigMF facilitates thesharing of data, prevents the "bitrot" of datasets wherein details of thecapture are lost over time, and makes it possible for different tools to operateon the same dataset, thus enabling data portability between tools and workflows.

SigMF signal recordings typically involve a data file (e.g., a binary file of IQor RF samples) and a metadata file containing plain text that describes the data.Together these files represent one recording, such asexample.sigmf-data andexample.sigmf-meta. Here is a minimal example of a SigMF.sigmf-meta file:

{"global": {"core:datatype":"cf32_le","core:sample_rate":1000000,"core:hw":"PlutoSDR with 915 MHz whip antenna","core:author":"Art Vandelay","core:version":"1.2.0"    },"captures": [        {"core:sample_start":0,"core:frequency":915000000        }    ],"annotations": []}

There are at least four ways you can use SigMF today, thanks to the community-supported projects:

1. WithinPython, using theofficial SigMF Python packagesigmf available from pip:pip install sigmf.
2. WithinC++ using theheader-only C++ librarylibsigmf.
3. WithinGNU Radio using the built-in SigMFsource &sink blocks.
4. Manually, using our examples and thespec itself, even if it's simply editing a text file.

The SigMF standards effort is organized entirely within this Github repository.Questions, suggestions, bug reports, etc., are discussed inthe issuetracker, feel free to createa new issue and provide your input, even if it's not a traditional issue.Changes to the specification only occur throughPull Requests.This ensures that the history and background of all discussions and changes are maintained for posterity.

There is also a SigMF chat room onGNU Radio's Matrix chat serverwhere you can ask SigMF-related questions, or participate in various discussions.Lastly, there are monthly SigMF calls covering a variety of topics, on the third Monday of each monthat 11:30AM Eastern/New York Time, please emailmarc@gnuradio.org for an invite and Zoom link.

Anyone is welcome to get involved - indeed, the more people involved in thediscussions, the more useful the standard is likely to be!

The "Core" SigMF standard is intentionally kept limited in scope, additional metadata fields can be added throughSigMF Extensions. For example, thesignal extension provides a standard way to specify modulation schemes and other attributes of wireless comms signals. Several general purpose canonical extensions live within this repository directly in theextensions directory, while others are maintained by third parties. Below are some popular sources for SigMF extensions. To have your extension reviewed for inclusion on this list, please open a PR adding the repository to the list below:

• SigMF's Community Extension Repository
• NTIA's series of extensions

In general, extension publication pull requests should go into the Community Extension repository. Occasionally there is an extension that is so general purpose that it may be warranted to include in the core SigMF Repositoryextensions directory. Opening an issue in this repository for discussion (or noting this in a pull request in the Community Extension repository), or discussing on the SigMF Matrix Chat room is the best way to make that happen.

Software that seeks to perform validation on metadata can open a metafile, parse which extensions are used (if any), then pull the core JSON schema plus the JSON schemas for each extension being used (and optionally, an application-specific schema), then merge the global/captures/annotations objects between all schemas, and disableadditionalProperties for all three so that typos can be detected.

The main pdf is generated using the following content:

1. sigmf-schema.json - global/captures/annotations tables and descriptions, as well as the Abstract
2. collection-schema.json - Collection object documentation
3. additional_content.md - mix of plaintext/markdown/latex for the remaining sections of the document

The scriptdocs-generator.py uses Python, PyLaTeX, Pandoc, and Inkscape to create the specifications document in PDF and HTML formats.

Instead of generating the docs locally, you can make your change (e.g., using GitHub's web interface), open up a PR, and then under GitHub's "Actions" menu at the top, click the run that corresponds to your PR, scroll down to "Artifacts", download the artifact named "compiled_docs", unzip it, and you should be able to see the html and pdf.

No, this is not a GNU Radio specific effort. This effort first emerged froma group of GNU Radio core developers, but the goal of the project is to providea standard that will be useful to anyone and everyone, regardless of tool orworkflow.

No, similar to the response, above, the goal is to create something that isgenerally applicable tosignal processing, regardless of whether or not theapplication is RF or communications related.

Yes, and in most cases this is by design. Since the goal of this project iscreate a broadly useful standards document, it is in our best interest to makesure we gather and consider as many opinions as possible, and produce theclearest and most exact language possible. This necessarily requires extremeattention to detail and diligence.