Neets Master Glossary

1-60 RANGE-HEIGHT INDICATOR—A radar display on which slant range is shown along the X axis and height along the Y axis [18]. RANGE MARKER—A movable vertical pulse on an A-scope or a ring on a PPI scope used to measure the range of an echo or to calibrate the range scale [18]. RANGE RESOLUTION—Ability of a radar to distinguish between targets that are close together [18]. RANGES—The several upper limits a meter will measure as selectable by a switch or by jacks; for example, a voltmeter may have ranges of 1 volt, 2.5 volts, 10 volts, 25 volts, and 100 volts [3]. RANGE STEP—On an A-scope sweep, a vertical displacement used to measure the range of an echo [18]. RAREFIED WAVE—A longitudinal wave that has been expanded or rarefied (made less dense) as it moves away from the source [10]. RATE GYRO—A gyro used to detect and measure angular rates of change [15]. RATIO—The value obtained when one number is divided by another. This value indicates the relative proportions of the two numbers [2]. RATIO DETECTOR—A detector that uses a double-tuned transformer to convert the instantaneous frequency variations of the FM input signal to instantaneous amplitude variations [12]. RATIO OF TRANSMITTED POWERS—The power ratio (FSK versus AM) that expresses the overall improvement of FSK transmission when compared to AM under rapid-fading and high-noise conditions [12]. RC CONSTANT—Time constant of a resistor-capacitor circuit; equal in seconds to the resistance value in ohms multiplied by the capacitance value in farads [2] [9]. RC DIFFERENTIATOR—An RC circuit in which the output is taken from the resistor [9]. RC FILTER—A filter used in applications where load current is low and constant, and voltage regulation is not necessary [7]. RC INTEGRATOR—An RC circuit in which the output is taken from the capacitor [9]. RC NETWORK—A circuit containing resistance and capacitance arranged in a particular manner to perform a specific function [9]. RC OSCILLATOR—An oscillator in which the frequency is determined by resistive and capacitive elements [9]. REACTANCE—The opposition offered to the flow of an alternating current by the inductance, capacitance, or both, in any circuit [2]. REACTANCE AMPLIFIER—A low-noise amplifier that uses a nonlinear variable reactance as the active element instead of a variable resistance. Also called a parametric amplifier [11]. REACTANCE TUBE—A tube connected in parallel with the tank circuit of an oscillator. Provides a signal that will either lag or lead the signal produced by the tank [12]. REACTANCE-TUBE MODULATOR—An FM modulator that uses a reactance tube in parallel with the oscillator tank circuit [12].