Carrier acquisition and tracking by a COSTAS-loop with automatic frequency control
Abstract
The use of automatic frequency control (AFC) in a Costas Loop is studied. The AFC control characteristics for phase shift keying modulated nonreturn-to-zero signals, as well as the corresponding acquisition times, were derived for passive lowpass filters. Signal tracking of the composite Costas/AFC Loop was analyzed. Shorter acquisition times and greater acquisition ranges are obtained. False carrier locking at data sidebands is avoided. The AFC block can be switched off after acquisition to improve tracking quality.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- June 1983
- Bibcode:
- 1983STIN...8417202M
- Keywords:
-
- Automatic Frequency Control;
- Phase Shift Keying;
- Spacecraft Communication;
- Demodulation;
- Global Positioning System;
- Phase Lock Demodulators;
- Sidebands;
- Tracking Problem;
- Astrodynamics