AF CPS EHF HF Hz MF RF SHF UHF VHF VLF carrier frequency cycles extremely high frequency frequency frequency spectrum fundamental fundamental tone harmonic hertz high frequency intermediate frequency intonation kilocycles kilohertz low frequency lower frequencies medium frequency megacycles megahertz monotone monotony overtone partial partial tone pitch radio frequency spark frequency spectrum superhigh frequency tone tonelessness ultrahigh frequency upper frequencies very high frequency very low frequency