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PARASITIC ARRAY—An antenna array containing one or more elements not connected to the
transmission line [10] [18].
PARASITIC ELEMENT—The passive element of an antenna array that is connected to neither the
transmission line nor the driven element [10].
PART—A part is one component or two or more components joined together. It is not normally subject to
disassembly without destruction [17].
PASSIVE SATELLITE—A satellite that reflects radio signals back to earth [17].
PATCH PANEL—A panel used to tie a receiver or transmitter to its associated equipment [17].
PEAK AMPLITUDE—The maximum value above or below the reference line [12].
PEAK CURRENT—The maximum current that flows during a complete cycle [6].
PEAK DETECTION—Detection that uses the amplitude of pam or the duration of pdm to charge a holding
capacitor and restore the original waveform [12].
PEAKING COIL—An inductor used in an amplifier to provide high-frequency compensation, which
extends the high-frequency response of the amplifier [8].
PEAK POWER—The maximum value of the transmitted pulse [12].
PEAK-REVERSE VOLTAGE—The peak ac voltage that a rectifier tube will withstand in the reverse
direction [6].
PEAK-TO-PEAK—The measure of absolute magnitude of an ac waveform, measured from the greatest
positive alternation to the greatest negative alternation [2].
PEAK VALUE—The maximum instantaneous value of a varying current, voltage, or power. It is equal to
1.414 times the effective value of a sine wave [2].
PEAK VOLTAGE—The maximum value present in a varying or alternating voltage. This value may be
positive or negative [6].
PENTAVALENT IMPURITY—A type of impurity that contains five valence electrons and donates one
electron to the doped material. Also called DONOR IMPURITY [7].
PENTODE TUBE—A five-electrode electron tube containing a plate, a cathode, a control grid, and two
grids [6].
PERCENT OF MODULATION—The degree of modulation defined in terms of the maximum permissible
amount of modulation [12].
PERFORATOR—A device that stores a teletypewriter message on a paper tape [17].
PERIGEE—The point in the orbit of a satellite closest to the earth [17].
PERIOD TIME—The time required to complete one cycle of a waveform [2] [10] [12].
PERIODIC WAVE—A waveform that undergoes a pattern of changes, returns to its original pattern, and
then repeats the same pattern of changes. Examples are square waves, rectangular waves, and sawtooth
waves [9].
