"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"
Previous set of "F" Definitions and Terms.
FRACTIONAL T1. In the North American or Japanese hierarchies, the tariffed use of a data rate
corresponding to fewer than the 24 channels served by a T1 line.
FRAME. A portion of a message. The frame is any construction system fitted and united together, designed for mounting
or supporting electrical or electronic parts or units.
FRAME RELAY. An interface protocol for statistically multiplexed packet-switched data communications in
which (a) variable-sized packets (frames) are used that completely enclose the user packets they
transport, and (b) transmission rates are usually between 56 kb/s and 1.544 Mb/s (the T-1 rate).
FRAMING. The process of synchronizing a facsimile receiver to a transmitter. This allows proper picture
reproduction.
FREE-SPACE LOSS. The loss of energy of radio waves caused by the spreading of the wavefront as it
travels from the transmitter.
FREQUENCY (f). The number of complete cycles per second existing in any form of wave motion,
such as the number of cycles per second of an alternating current. The rate at which the
vector that generates a sine wave rotates.
FREQUENCY COMPENSATION NETWORK. Circuit modification used to improve or broaden the
linearity of its frequency response.
FREQUENCY CUTOFF. The frequency at which the filter circuit changes from an action of rejecting the
unwanted frequencies to an action of passing the desired frequencies. Conversely, the point at which the
filter circuit changes from an action in which it passes the desired frequencies to an action in which it
rejects the undesired frequencies.
FREQUENCY-DETERMINING NETWORK. A circuit that provides the desired response (maximum
or minimum impedance) at a specific frequency.
FREQUENCY DEVIATION. The amount the frequency varies from the carrier frequency.
FREQUENCY DIVERSITY. Transmitting (and receiving) of radio waves on two different frequencies
simultaneously.
FREQUENCY-DIVISION MULTIPLEXING. Multiplexing that transmits and receives the full 360
degrees of each sine wave.
FREQUENCY METER. A meter used to measure the frequency of an ac signal. An electronic instrument that displays the frequency of an incoming signal. The frequency is determined by comparing the signal to the counter's time base oscillator. [Frequency Meter Manufacturers]
FREQUENCY MIXER. A circuit that accepts two input signals at two different frequencies, and produces an output frequency equal to the difference of the two inputs. [Frequency Meter Manufacturers]
FREQUENCY MODULATION (fm). A signaling method that varies the carrier frequency in proportion to the amplitude of the modulating signal. Angle modulation in which the modulating signal causes the
carrier frequency to vary. The amplitude of the modulating signal determines how far the frequency
changes, and the frequency of the modulating signal determines how fast the frequency changes.
FREQUENCY MULTIPLIERS. Special RF power amplifiers that multiply the input frequency. A circuit that converts an incoming signal to a higher frequency by adding a fixed multiple of cycles or pulses to the signal. [RF Frequency Doubler Manufacturers].
FREQUENCY RESPONSE. The measurement of how a circuit or device reacts to different frequencies that are applied to it. The part of a frequency regain than can be sensed by a device. The measure of a servo’s ability to respond to various input frequencies.
FREQUENCY-RESPONSE CURVE. A curve showing the output of an amplifier (or any other device)
in terms of voltage or current plotted against frequency with a fixed-amplitude input signal.
FREQUENCY SCANNING. Varying the output frequency to achieve electronic scanning.
FREQUENCY-SHIFT KEYING (fsk). Frequency modulation somewhat similar to continuous-wave
(cw) keying in AM transmitters. The carrier is shifted between two differing frequencies by opening
and closing a key.
FREQUENCY STABILITY. Refers to the ability of an oscillator to accurately maintain its operating
frequency. The degree to which an oscillating signal produces the same frequency for a specified interval of time [short-term stability, or long-term stability].
FREQUENCY STANDARD. An oscillator used as a reference source for frequency measurements.
FREQUENCY SYNTHESIS. A process that uses hetrodyning and frequency selection to produce a signal.
FREQUENCY SYNTHESIZER. A frequency source of high accuracy. A bank of oscillators
in which the outputs can be mixed in various combinations to produce a wide range of frequencies.
Next "F" Definitions and Terms
