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frequency hopping

Definition/Scope: Frequency hopping is the repeated switching of frequencies during radio transmission is one way to minimize unauthorized interception or jamming of telecommunications. The overall bandwidth required for frequency hopping is much wider than that required to transmit the same information using only one carrier frequency. By itself, frequency hopping provides only limited protection against eavesdropping and jamming. To get around this weakness most modern military frequency hopping radios often employ separate encryption devices such as the KY-57. U.S. military radios that use frequency hopping include HAVE QUICK and SINCGARS. The major disadvantage to using frequency hopping is that the synchronization of both radios must be perfect to each other. The overall bandwidth required for frequency hopping is much wider than that required to transmit the same information using only one carrier frequency. However, because transmission occurs only on a small portion of this bandwidth at any given time, the effective interference bandwidth is really the same. While it may not provide extra protection against wideband thermal noise, the frequency-hopping approach does reduce the degradation caused by narrowband interferers.



Broader Terms:

multiplexing communication

Related Terms:

Extremely High Frequency
Multifunctional Information Distribution System
SINCGARS
time division multiple access
ultrahigh frequency
very high frequency


CALL Homepage >> Thesaurus Last Updated: Sept 17, 2008