| dc.description |
Scores on the Diagnostic Rhyme Test (DRT), which is widely used to evaluate military voice systems, were compared with intelligibility scores for the International Civil Aviation Organization (ICAO) spelling alphabet words (ALFA, BRAVO, etc.) under different radio-jamming conditions. For ordinary use, a DRT score below 70 is generally considered unacceptable. In these tests, spelling alphabet intelligibility was over 90% when the DRT score was just below 70. This suggests that, for the distinctive vocabularies used in military communications, reasonable levels of intelligibility can be maintained even under relatively severe degradation. With intermittent jamming, intelligibility improved dramatically and in some cases was better than would be expected from simple averaging based on jammer on/off time. Confusions among the spelling alphabet words were also examined, and single-syllable words were found to be particularly susceptible to confusions. |
