Performance of voice coders under military conditions

Discusses voice coding in military situations. Most vocoder systems are specified and sold on the basis of good quality speech being available at the input terminal. The exception being the use of a hands-free microphone in an automobile. Military vehicles including armoured vehicles and helicopters can produce very high acoustic fields with components in the critical band which includes the fundamental larynx pitch. Modern approaches to warfighting put emphasis on coalition operations and interoperability is the name of the game. Although some international standards for military voice coding exist, it is highly likely that a tandem circuit between two allies will involve the transcoding of speech between two differing coding schemes. The advent of lower rate voice coding in civil systems also brings the problem of military systems interoperating with civil ones