All-digital AFSK modem with Viterbi detection for TT&C CubeSat transceiver
Rubem Vasconcelos Pacelli, Antonio Macilio Pereira de Lucena, Joao Cesar Moura Mota

DOI: 10.14209/SBRT.2020.1570654898
Evento: XXXVIII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT2020)
Keywords: AFSK modem Viterbi detector CubeSat transceiver
Abstract
Audio-Frequency Shift Keying (AFSK) with continuous phase modulation and non-coherent demodulation is widely used on the telecommand channel of the most TT&C transceivers for CubeSat. However, this solution has low efficiency in terms of power. In this paper, a new all-digital AFSK modem is proposed. The demodulator uses the Viterbi algorithm to perform the maximum likelihood sequence detection (MLSD) and gives an expressive gain when compared to non-coherent detection. Original mathematical analyzes are presented to explain the proposed system. Some performance results, determined via computational simulation, are presented and discussed.

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