LF - Low Frequency HF - High Frequency HF - high-frequency DF - Dual Frequency RF - Radio Frequency MF - Multi-frequency AF - Audio frequency FF - Fixed Frequency V.F. - Video Frequency V.F. - Voice Frequency VF - Video Frequency VF - Voice Frequency MF - Medium Frequency FD - frequency domain FH - Frequency Hopping LMF - Low Mid Frequency VLF - Very Low Frequency TTF - The Time Frequency CF - Constant Frequency EF - Extended Frequency FD - Frequency division FZO - Frequency Zero One LFD - Low Frequency Data V.F. - Variable Frequency VF - Variable Frequency XF - Extended Frequency VHF - Very High Frequency ULF - Ultra low frequency VHF - Very High-Frequency FM - frequency modulated SLF - Super low frequency FSK - Frequency Shift Key LFN - Low Frequency Noise HFW - High Frequency Word HPF - High Pass Frequency LFL - Low Frequency Limit MF - Mandatory frequency MFH - Mid Frequency Horns TFS - The Frequency Shift VLF - Very Long Frequency UHF - Ultra High Frequency FM - Frequency Modulation LFA - Low Frequency Active LFA - Low-Frequency Active SHF - Super high frequency LFE - Low Frequency Effect HFW - High Frequency Words HFN - High Frequency Noise QTF - Query Term Frequency BPF - Blade Pass Frequency