Accession Number:

AD0849465

Title:

Effects of Selective System Parameters on Communications Intelligibility.

Descriptive Note:

Final rept.,

Corporate Author:

NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTER ATLANTIC CITY NJ

Personal Author(s):

Report Date:

1969-03-01

Pagination or Media Count:

64.0

Abstract:

The communications frequency study was made to facilitate spectrum planning by FAA Frequency Management personnel. The study relates communications intelligibility to frequency channel spacing, bandwidth, modulation type, and signal-to-interference ratio. The overall approach was to conduct talkerlistener intelligibility tests, voice communications equipment tests, and digital communications equipment tests. The test procedure subjected the Speech Communications Index Meter SCIM simulated speech signals, the Air Traffic Control ATC messages, and the Modified Rhyme Tests MRTs to specific levels of interference. The SCIM signal was first applied to the SCIM analyzer for computation and display of articulation index AI. The ATC messages and MRTs were then recorded at the configuration which produced these discrete values of AIs. These recordings were subsequently used to perform subjective intelligibility testing. Talkerlistener intelligibility tests were conducted to determine the particular values of AI required for communications links within the ATC system using both ATC and MRT vocabularies. Voice and digital communications tests were conducted to obtain data pertaining to channel assignments for various configurations of conventional and proposed operational modes.

Subject Categories:

  • Air Navigation and Guidance
  • Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE