From Introduction to Electronic Defense Systems, Second Edition

Glossary

Symbols

?
absorptance
?
difference channel of a monopulse radar
? f
frequency interval or difference
?
emissivity; also a general measure of precision
? B
width at half-power (-3 dB) beam (i.e., angle within which the power of the transmitted signal is more than half its maximum level)
? q
squint angle
?
wavelength: distance between two adjacent peaks on a sinusoidal wave; for an electromagnetic wave the wavelength is given by c/f where c is the velocity of light and f is the frequency of the wave
?
reflectance or reflection coefficient
? r
reflection coefficient of a rough surface
? s
specular reflection coefficient
?
sum channel of a monopulse radar
?
Stefan-Boltzmann constant
?
equivalent area
?
standard deviation (i.e., square root of the variance of a probability distribution; a quantity whose values have a Gaussian distribution has a 67% probability of being within ? of the mean; 90% probability of being within 2 ?; 97% probability of being within 3 ?)
? p
standard deviation of a quantity with zero mean
?
pulse duration, pulsewidth (PW)
? a
atmospheric transmittance
? 0
transmittance of optical system
?
phase or phase shift angle
?
field of view, measured as a solid angle
?
angular velocity or angular frequency of a signal

A-C

AAA
anti-aircraft artillery
AAM
air-to-air missile
ac
alternating current
A/D, ADC
analog-to-digital converter
a e
radius of the Earth (8.5 10 6ms)
A eff

Products & Services
Linear Polarizers
Linear polarizers transmit light waves along one axis and absorb them along the other. The transmitting and absorbing axes of linear polarization are oriented at 90 degrees to each other.
Wavelength Meters
Wavelength meters are devices that measure the wavelength of electromagnetic waves.
UV and Visible Spectrometers
UV and visible spectrometers measure the amount of ultraviolet (UV) and visible light transmitted or absorbed by a sample placed in the spectrometer.
Circular Polarizers
Circular polarizers block all photons rotating in one direction while allowing those rotating in the opposite direction to pass. They are assemblies that consist of a linear polarizer and a wave retarder, usually a quarter waveplate or half waveplate.
Radar Absorbing Materials
Radar absorbing materials and structures are designed to absorb radar waves and convert them to heat. Because these radar waves are not returned, radar absorbing materials (RAM) and radar absorbing structures (RAS) provide a reduced signature for detection.

Topics of Interest

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