PSK SUBCARRIER DEMODULATORS FOR DATA ACQUISITION

THIS REPORT ANALYZES AND DISCUSSES THE USE OF PSK (PHASE SHIFT KEYING) SUBCARRIER DEMODULATORS TO OVERCOME THE NOISE DEGRADATION AND FILTERING ERRORS ASSOCIATED WITH SIGNAL CONDITIONERS NOW BEING USED AS DEMODULATORS FOR LOW DATA RATE PCM/PSK. IT IS SHOWN THAT A PSK SUBCARRIER DEMODULATOR PROVIDES VERY CLOSE TO IDEAL PERFORMANCE. THE SIGNAL CONDITIONERS, WHICH WERE NOT DESIGNED FOR THE SUBCARRIER DEMODULATION FUNCTION, ARE DEFICIENT IN THE FOLLOWING AREAS: IMPROPER FILTERING OF THE SIGNAL PRIOR TO SQUARING FOR SUBCARRIER REGENERATION, LOW SENSITIVITY OF PHASE LOCK LOOP AND FILTERING MATCHED TO THE SUBCARRIER RATE RATHER THAN THE DATA RATE. BECAUSE THE ENVISIONED PSK DEMODULATOR CAN BE OPTIMIZED FOR THESE FUNCTIONS, IT WILL PROVIDE ABOUT 10 DB MORE SENSITIVITY AT THRESHOLD THAN IS NOW BEING ACHIEVED. /AUTHOR/

• Corporate Authors:

  National Aeronautics and Space Administration

  Goddard Space Flight Center
  Greenbelt, MD  United States 
• Authors:
  • Dilosa, V J
  • Simas, V R
  • Saliga, T V
• Publication Date: 1967-4

Subject/Index Terms

• TRT Terms: Data collection; Modulation; Phase shift (Electricity); Pulse code modulation; Signals
• Old TRIS Terms: Modulators; Phase shift
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225216
• Record Type: Publication
• Source Agency: Traffic Systems Reviews & Abstracts
• Report/Paper Numbers: Report No X-523-67-214
• Files: TRIS
• Created Date: Sep 12 1994 12:00AM