Carrier acquisition and tracking by a COSTAS loop with automatic frequency control
Abstract
Signal reconstruction for demodulation from the BPSK-modulated suppressed carrier by COSTAS demodulation is discussed. For heavily faded mobile communications such as satellite-aided mobile communication, carrier acquisition lasts too long for most applications, and for a large frequency uncertainty range, false carrier locking leads to an erroneous demodulation. Both disadvantages can be avoided by an automatic frequency control (AFC) inserted into the COSTAS loop. The AFC characteristics for BPSK-modulated NRZ signals, and the corresponding acquisition times, are derived for passive low pass filters. The signal tracking of the composite COSTAS/AFC loop is analyzed.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- April 1984
- Bibcode:
- 1984STIN...8513149M
- Keywords:
-
- Automatic Frequency Control;
- Carrier Frequencies;
- Demodulation;
- Signal Processing;
- Low Pass Filters;
- Phase Shift Keying;
- Signal Analysis;
- Spacecraft Communication;
- Communications and Radar