About: http://webisa.webdatacommons.org/91537874

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	If a signal does not change at all, it never completes a cycle, so its frequency is a Hz.
http://www.w3.org/ns/prov#wasQuotedFrom	docstoc.com