Accurate detection of satellite beacon polarization states using cascaded heterodyne phase-locked loops
Abstract
A technique using cascaded heterodyne phase-locked loops is developed to accurately detect the phases and amplitudes of both copolarized and cross-polarized beacons under poor carrier-to-noise (C/N) ratio conditions. Both the copolarized and cross-polarized signals are down-converted to a local reference frequency using a primary heterodyne phase-locked loop (PLL-1) locked to a copolarized signal. A secondary phase-locked loop (PLL-2) is then used to further reduce the noise bandwidth of the cross-polarized signal by about 30 dB. Using this feature, the lower C/N ratio in the cross-polarized signal is approximately compensated for.
- Publication:
-
IEEE Transactions on Communications
- Pub Date:
- January 1982
- Bibcode:
- 1982ITCom..30..283T
- Keywords:
-
- Cascade Control;
- Communication Satellites;
- Phase Error;
- Phase Locked Systems;
- Polarization Characteristics;
- Radio Beacons;
- Coplanarity;
- Cross Polarization;
- Feedback Control;
- Optical Heterodyning;
- Transfer Functions;
- Variance (Statistics);
- Space Communications, Spacecraft Communications, Command and Tracking