frequency modulated altimeter
frequency modulated sonar
linear frequency modulated continuous wave
linear frequency modulated signal
radar frequency synthesizer
stepped frequency radar
very high frequency radar
audio frequency and video frequency processing
correlation in frequency domain and frequency domain
High frequency and low frequency
Low Frequency and Acoustic Frequency
Low Frequency and Medium Frequency Therapy Equipment
theoretical frequency and actual frequency
Active Radar and Passive Radar
(Ultra) high frequency time series
~(87)Rb atomic frequency standard
10 kV frequency converter