"A",
"B",
"C",
"D",
"E",
"F",
"G",
"H",
"I",
"J",
"K",
"L",
"M",
"N",
"O",
"P",
"Q",
"R",
"S",
"T",
"U",
"V",
"W",
"X",
"Y",
"Z"
Previous set of "P" definitions and terms.
POWER (AVERAGE) FOR PULSED RADARS: Average power for a pulse radar is the average power
transmitted between the start of one pulse and the start of the next pulse (because the time between pulses is many times
greater than the pulse duration time, the average power will be a small fraction of peak power).
For this example: Peak Power = 1 MW, Pulse Time (t) = 0.5 micro-second,
and Interval Between Pulses (T) = 1000 microseconds (1000 pps).
Peak Power = Pwr during pulse time (t) = 1 MW = 106 Watts = 90 dBm.
Avg Power = Average Power During Time (T) = 106 x t/T
= 106 x 0.5/1000 = 0.5 x 103 = 0.5 kilowatt = 57 dBm or 27 dBW
POWER GAIN: In an antenna, the ratio of its radiated power to that of a reference.
POWER OUTPUT: Power output of a transmitter or transmitting antenna is commonly expressed in dBW or dBm. One megawatt would be expressed as 60 dBW or 90 dBm:
POWER (PEAK) FOR PULSED RADARS: Peak power for a pulsed radar is the power radiated during the actual
pulse transmission (with zero power transmitted between pulses).
POWER FOR CW RADARS: Since the power output of CW transmitters (such as illuminator transmitters)
usually have a duty cycle of one (100%), the peak and average power are the same.
POWER DENSITY: The density of power in space expressed in Watts/meter2 , dBW/m2, etc. Generally used in
measurements above 100 MHz. At lower frequencies, field intensity measurements are taken.
PPI-SCOPE: A radar display yielding range and azimuth (bearing) information via an intensity modulated display
and a circular sweep of a radial line. The radar is located at the center of the display.
PREAMPLIFIER (PREAMP): An amplifier that raises the output of a low-level source for further
processing without appreciable degradation of the signal-to-noise ratio.
PRESELECTOR: A device placed ahead of the mixer in a receiver, which has bandpass characteristics such that the desired (tuned) RF signal, the target return, is
allowed to pass, and other undesired signals (including the
image frequency) are attenuated.
PRIMARY RADIATION: Radiation that is incident upon a
material and produces secondary emission from the material.
PROBE COUPLER: A resonant conductor placed in a waveguide or cavity to insert or extract energy. [RF Coupler Manufacturers]
PROPAGATION: In electrical practice, the travel of waves through or along a medium. The path traveled by the wave in getting from one point to another is known as
the propagation path (such as the path through the atmosphere in getting from a transmitting antenna to a receiving antenna, or the path through the waveguides and other microwave devices in getting from an antenna to a receiver).
Next set of "P" definitions and terms.
