Fast carrier recovery in FHSS systems with DDS based Costas loop
Journal Title: Elektronika - Year 2015, Vol 19, Issue 1
Abstract
Owing to fast change of carrier frequency, the usage of coherent demodulation methods in Frequency-Hopping Spread Spectrum (FHSS) communication systems is limited by the coherent state acquisition performed by the local oscillator. To get around this difficulty, it is needed to implement the circuit within the FHSS system that is able to rapidly generate a coherent carrier. The work presented in this paper proposes a realization of Costas loop based on a combination of Direct Digital Synthesis (DDS), (Temperature-Compensated) Voltage Controlled Oscillator ((TC)VCXO), and Phase-Locked Loop (PLL), which in particular enables a short period (less than 100 μs) required for a local oscillator to reach the coherent state. The implemented model is thoroughly described with measurements results also provided.
Authors and Affiliations
Slavko Šajić
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