<https://www.edaboard.com/threads/help-me-reduce-the-variation-of-the-ring-vco-output.1830/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.edaboard.com/threads/help-me-reduce-the-variation-of-the-ring-vco-output.1830/#post-397878>