Development of the 61.152-kHz Subsystem of the Decision Information Distribution System.
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 demodulator/decoder 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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1971
- Accession Number
- AD0728492
Entities
People
- Gene G. Ax
- Hiroshi Akima
- R. Marshall Coon