A New Carrier Recovery Circuit for Land Mobile Satellite Communication

This paper proposes a DCF (dual carrier filter) reverse modulation type carrier recovery circuit to achieve a low carrier skipping rate and satisfactory phase tracking performance for coherent detection of PSK (phase shift keying) signals in fast Rician fading channels. The proposed scheme employs both narrow and wide bandwidth carrier filters simultaneously for the reverse modulation type carrier recovery circuit. It is clarified by computer simulation that the Pe performance of a QPSK (quadriphase shift keying) modem employing the proposed scheme shows an improvement of 1.5 dB in required Es/N₀ at Pe = 10^-4 (after Viterbi decoding (R = 7/8, K = 7), C/M (direct-to-multipath signal power ratio) = 10 dB, interleaving size = 64 × 64), compared with conventional coherent detection employing the reverse modulation tank-limiter scheme or the Costas loop scheme.