Improved Digital Costas Loop Design in Spread Spectrum Communication

Based on software radio technique, a novel improved design structure of digital Costas loop for spread spectrum communication is put forward in the paper. Main practical works includes: (1) For carrier recovery in the traditional Costas central, it improves a way applicable to the spread spectrum communication and gives a detailed mathematical deduction; (2) As for traditional QPSK modem methods, it joins the encoding, interleaving, deinterlacing, decoding, balanced module in the QPSK modulation and demodulation process in spread spectrum communications to reduce the system Bit error rate (BER); (3) a PN code magna-scope demodulator and two low power filers are added in order to get sensitive weighing signal. Simulation contrast results show that the improvement is feasible.