PARASITIC ARRAYAn antenna array containing one or more elements not connected to the
transmission line  .
PARASITIC ELEMENTThe passive element of an antenna array that is connected to neither the
transmission line nor the driven element .
PARTA part is one component or two or more components joined together. It is not normally subject to
disassembly without destruction .
PASSIVE SATELLITEA satellite that reflects radio signals back to earth .
PATCH PANELA panel used to tie a receiver or transmitter to its associated equipment .
PEAK AMPLITUDEThe maximum value above or below the reference line .
PEAK CURRENTThe maximum current that flows during a complete cycle .
PEAK DETECTIONDetection that uses the amplitude of pam or the duration of pdm to charge a holding
capacitor and restore the original waveform .
PEAKING COILAn inductor used in an amplifier to provide high-frequency compensation, which
extends the high-frequency response of the amplifier .
PEAK POWERThe maximum value of the transmitted pulse .
PEAK-REVERSE VOLTAGEThe peak ac voltage that a rectifier tube will withstand in the reverse
PEAK-TO-PEAKThe measure of absolute magnitude of an ac waveform, measured from the greatest
positive alternation to the greatest negative alternation .
PEAK VALUEThe maximum instantaneous value of a varying current, voltage, or power. It is equal to
1.414 times the effective value of a sine wave .
PEAK VOLTAGEThe maximum value present in a varying or alternating voltage. This value may be
positive or negative .
PENTAVALENT IMPURITYA type of impurity that contains five valence electrons and donates one
electron to the doped material. Also called DONOR IMPURITY .
PENTODE TUBEA five-electrode electron tube containing a plate, a cathode, a control grid, and two
PERCENT OF MODULATIONThe degree of modulation defined in terms of the maximum permissible
amount of modulation .
PERFORATORA device that stores a teletypewriter message on a paper tape .
PERIGEEThe point in the orbit of a satellite closest to the earth .
PERIOD TIMEThe time required to complete one cycle of a waveform   .
PERIODIC WAVEA 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