Radar Definitions
"A",
"B",
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"
'Fa' to 'Fq', 'Fr' to 'Fz'
Frequency Agility: A radar's ability to change frequency within its operating band, usually on a pulse-to-pulse
basis. This is an ECCM technique employed to avoid spot jamming and to force the jammer to go into a less effective barrage mode.
Frequency Agility Radar: A radar that automatically or semi-automatically tunes through a discrete set of operating frequencies in its normal mode of operation.
Frequency Band: A continuous range of frequencies. [Table of Frequency Bands]
Frequency Compensation Network: A circuit modification used to improve or broaden the
linearity of its frequency response.
Frequency Diversity Radar: A radar system technique, employed primarily as an anti-jamming feature, where the transmitter output frequency varies randomly from pulse to pulse over a wide frequency range.
Frequency Range: A specifically designated portion of the frequency spectrum; of a device, the band
of frequencies over which the device may be considered useful with various circuit and operating conditions; of a
transmission system, the frequency band in which the system is able to transmit power without attenuating or distorting it more than a specified amount.
Frequency Scanning: Varying the output frequency to achieve electronic scanning.
Frequency Shift Keying: [FSK] A form of FM where the carrier is shifted between two frequencies in accordance with a predetermined code. In multiple FSK, the carrier is shifted to more than two frequencies. FSK is used principally with teletype communications.
Frequency Spectrum: In a radar, the entire range of frequencies contained in an RF pulse or signal. A band of frequencies required by a transmission.
Frequency Synthesizer: A bank of oscillators in which the outputs can be mixed in various
combinations to produce a wide range of frequencies.
"FRUIT": In a radar beacon system, a type of interference, caused by beacon replies to interrogation asynchronous with the observer's interrogator. The largest amount of this interference is received through the side-lobes of the interrogating antenna, but it can become dense enough to cause false target indications.
FTC: (Fast Time Constant) An anti-jam feature employed in radar systems where receiver circuits may be
selected to provide a short time constant to emphasize signals of short duration to produce discrimination against the low frequency components of clutter. Also an electrical engineering term for the rate of charge or discharge of a capacitor.
Fundamental Frequency: Depending on the application the term is used synonymously for tuned frequency, carrier frequency, center frequency, output frequency, or operating frequency.
