Accession Number:

AD0728492

Title:

Development of the 61.152-kHz Subsystem of the Decision Information Distribution System.

Descriptive Note:

Technical memo.,

Corporate Author:

OFFICE OF TELECOMMUNICATIONS BOULDER COLO INST FOR TELECOMMUNICATION SCIENCES

Report Date:

1971-07-01

Pagination or Media Count:

69.0

Abstract:

A feasibility model of a low-frequency subsystem for the Decision Information Distribution System DIDS was designed, developed, and successfully demonstrated. Based upon predetermined locations for ten primary receiver sites spaced rather uniformly throughout the contiguous United States, an optimum site was chosen for a 100 kW frequency-shift-keyed transmitter to operate at 61.152 kHz. A very unique and sophisticated bit synchronization technique had to be designed and developed for the transmitting and receiving system to meet very unusual operational restrictions. An optimum demodulatordecoder for a coded-binary noncoherent frequency-shift-keying NCFSK system was designed and developed to reduce required transmitter power to a minimum. An applicable scheme for signal acquisition was also developed. Laboratory tests indicated that experimental and theoretical performance agreed very closely. Very successful on-the-air tests tended to confirm the agreement. Author

Subject Categories:

  • Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE