Transceiver architecture and digital down converter design for a long distance, low power HF ionospheric link

This paper describes the digital transceiver design used for an HF ionospheric link between the Spanish Antarctic Base and Spain. First the platform is described, focusing on the direct conversion receiver performance in terms of adjacent channel interference rejection. Then the digital down converter implementation is explored. In this field different alternatives are evaluated and a methodology based on cascaded short FIR filter structures that minimizes the required arithmetic bit-width is proposed.