Appendix A1: Glossary

This glossary gives the meanings usually borne in the text of the main technical terms, especially the less self-evident. Shades of meaning might differ in other radar contexts, for example, air traffic control. Source references are [S] = New Shorter Oxford English Dictionary; [C] = Clapham C, Oxford Concise Dictionary of Mathematics. Glossary cross-entries are italicised.

A-C

Active device (active reflector)

Device such as a racon connected to a source of power and able to respond at greater power than that within the interrogation. ( Secondary radar reflector, for example, a radar target enhancer, where an onboard power supply augment response power.)

Algorithm

A precisely described routine procedure that can be applied and systematically followed through to a conclusion. [C].

Amplifier

Device increasing output power of input signal using power from an external source. Linear amplifiers do not distort the waveform.

See also Gain.

Analog(ue)

Designating, pertaining to, or operating with signals or information represented by a continuously variable quantity such as spatial position, voltage, etc. [S].

See also Digital.

Anaprop

Anomalous propagation caused by atmospheric refraction effects.

Antenna

Converts between current in a conductor and electromagnetic radiation in space. Usually a reciprocal device.

See also Reflector (scanner).

Aperture width, area

The effective electrical width, area of an antenna or other radiator.

Attenuation

(1) Scattering or absorption of electromagnetic energy as heat, usually expressed in dB. (2) Proportion of output energy entering a device or network such as a