Neets Master Glossary

1-41 LOGIC INSTRUCTION—Any instruction that executes a logic operation that is defined in symbolic logic, such as AND, OR, NAND, or NOR [13]. LOGIC OPERATION—A nonarithmetical operation in a computer, such as comparing, selecting, making references, matching, sorting, and merging, where the logical YES or NO quantities are involved [13]. LOGIC SWITCH—A diode matrix (See MATRIX) or other switching arrangement that is capable of directing an input signal to one of several outputs [13]. LOGIC SYMBOL—A symbol used to represent a logic element graphically. Also a symbol used to represent a logic operator [13]. LONGITUDINAL WAVES—Those waves in which the disturbance (back and forth motion) takes place in the direction of propagation. Sometimes called compression waves [10]. LONG-WIRE ANTENNA—An antenna that is a wavelength or more long at its operating frequency [10]. LOOP—A curved conductor that connects the ends of a coaxial cable or other transmission line and projects into a waveguide or resonant cavity for the purpose of injecting or extracting energy [10] [11]. LOOSE COUPLING—Inefficient coupling of energy from one circuit to another that is desirable in some applications. Also called weak coupling [11]. LOWER-FREQUENCY CUTOFF—The lowest frequency a circuit will pass [9]. LOWER SIDEBAND—All difference frequencies below that of the carrier [12]. LOWEST USABLE FREQUENCY—The minimum operating frequency that can be used for communications between two points [10]. LOW FREQUENCY—The band of frequencies from 30 kHz to 300 kHz [17]. LOW-LEVEL MODULATION—Modulation produced in an earlier stage than the final [12]. LOW-NOISE AMPLIFIER—See PREAMPLIFIER [18]. LOW-PASS FILTER—A filter that passes a majority of the low frequencies on to the next circuit and rejects, or attenuates, the higher frequencies. Also called a high-frequency discriminator [9] [12]. LSD—See LEAST SIGNIFICANT DIGIT [13]. LUMPED CONSTANTS—The properties of inductance, capacitance, and resistance in a transmission line [10]. LUMPED IMPEDANCE TUNING—The insertion of an inductor or capacitor in series with an antenna to electrically lengthen or shorten the antenna [10]. MACHINE KEYING—A method of cw keying using punched tape or other mechanical means to key a transmitter [12]. MAGIC T—See BALANCED MIXER [18]. MAGIC-T JUNCTION—A combination of H-type and E-type T-junctions [11].