Detection
42935
201555749
2008-03-28T12:03:47Z
Mynameisnotpj
5518378
{{Cleanup|date=March 2008}}
In general, '''detection''' is the extraction of information from any clear or clouded ambient or otherwise accessible stream of information without neither support from the sender nor synchronization to the sender.
In the history of [[radio]] communications, "detectors" where the first operable type of [[semiconductor]] [[diodes]] to extract modulated [[Signalling (telecommunications)|signal]] from their [[carrier]]. Still today, in multi-channel systems, '''detecting''' is the selective extraction of an [[Amplitude modulation|AM]] signal from its [[carrier wave|carrier]] [[frequency]].
In communications, '''detection''' is the extraction of [[intelligence (information gathering)|intelligence]] from a carrier signal in a stream of electro-magnetic energy. Note that this may be either an ''overt'' signal, as in a conventional [[radio]] broadcast, a ''noise'' signal as in heavily interfered ambient signals or a ''covert'' signal, as in [[steganography]].
In opto-electronic or other radiation systems, the '''detection''' means the generation of an electrical signal in response to a received optical input. For example, the optical signal received from an optical fiber is converted to an electrical signal in a [[detector]], often by a [[photodiode]].
In [[steganography]], attempts to detect encoded intelligence from suspected carrier material is referred to as [[steganalysis]]. Steganalysis has an interesting difference from most other types of detection, in that it can often only produce the [[probability]] of the existence of payload material encoded in the carrier; this is in contrast to the detection of signals which are simply [[encrypted]], as the [[ciphertext]] can often be detected with certainty, even if it cannot be decoded.
In the [[military]], detection means the special discipline of [[reconnaissance]] with the aim to recognize the presence of an object in a location or ambience.
Finally, the [[art of detection]], also known as ''following clues'', is the work of any [[detective]] [http://ca.geocities.com/t369@rogers.com/index.html].
==See also==
* [[Signal detection theory]]
[[Category:Communication]]
[[pl:detekcja]]