1-72
STEP-TRANSMISSION SYSTEM—A data transmission system that operates on direct current. It consists
of a step transmitter (rotary switch) and a step motor interconnected to transmit data (information)
between remote locations [15].
STICKOFF VOLTAGE—A low voltage used in multispeed synchrosystems to prevent false
synchronizations [15].
STOP—The last unit of a teletypewriter signal. It is always a mark [17].
STRANDED CONDUCTOR—A conductor composed of a group of wires. The wires in a stranded
conductor are usually twisted together and not insulated from each other [4].
STRANDS—Fine metallic filaments twisted together to form a single wire [4].
STRATOSPHERE—Located between the troposphere and the ionosphere; it has little effect on radio
waves [10].
STROBOSCOPE—An instrument that allows viewing of rotating or reciprocating objects by producing the
optical effect of a slowing down or stopping motion [16].
STUB—Short section of a transmission line used to match the impedance of a transmission line to an
antenna. Can also be used to produce desired phase relationships between connected elements of an
antenna [10] [18].
SUBASSEMBLY—Consists of two or more parts that form a portion of an assembly or a unit [17].
SUBHARMONIC—An exact submultiple of the fundamental frequency. Even subharmonics are one-half,
one-quarter, and so on. Odd subharmonics are one-third, one-fifth, and so on of the fundamental
frequency [17].
SUBSTRATE—Mounting surface for integrated circuits. May be semiconductor or insulator material
depending on type of IC [14].
SUDDEN IONOSPHERIC DISTURBANCE—An irregular ionospheric disturbance that can totally blank
out hf radio communications [10].
SUMMING NETWORK—A combination of two or more parallel resistors used in servosystems as an
error detector. The output of the network is the algebraic sum of the inputs [15].
SUPERHETERODYNE RECEIVER—A type of receiver that uses a mixer to convert the RF echo to an
IF signal for amplification [18].
SUPERHIGH FREQUENCY—The band of frequencies from 3 gigahertz to 30 gigahertz [17].
SUPERSONIC—(1) Speed greater than the speed of sound [10]. (2) Ultrasonic.
SUPPORT SYSTEM—For a radar, a system that provides an auxiliary input, such as dry air, electrical
power, or liquid cooling [18].
SUPPRESSION—The process of eliminating an undesired portion of a signal [17].
SURFACE WAVE—Radio waves that travel along the contours of the earth, thereby being highly
attenuated [10].
SWAMPING RESISTOR—A resistor used to increase or "broaden" the bandwidth of a circuit [8].
