出典:Wiktionary
出典:『Wiktionary』 (2011/12/26 00:14 UTC 版)
ultra low frequency (複数形 ultra low frequencies)
出典:Wikipedia
出典:『Wikipedia』 (2011/07/14 17:44 UTC 版)
Ultra low frequency (ULF) is the frequency range of electromagnetic waves between 300 hertz and 3 kilohertz. In magnetosphere science and seismology, alternative definitions are usually given, including ranges from 1 mHz to 100 Hz, 1 mHz to 1 Hz, 10 mHz to 10 Hz. Frequencies above 3 Hz in atmosphere science are usually assigned to the ELF range.