Feature: RF and microwave
Figure 1: Block diagram of the Quad-Apollo MxFE X-band digital beamforming platform
Phase application: Aſter determining the optimal clock phase combination, the corresponding phase settings are permanently applied to the targeted PLL ICs. Tis ensures that the selected phase offset aligns all converters in a configuration that minimises coherent spur reinforcement.
Iterative calibration: Te same process is repeated for additional PLL devices, always referencing the same fixed clock source. Tis iterative refinement gradually de-correlates clock spurs across all participating ICs, achieving a system wide reduction in spur amplitude.
System calibration: Following the spur de-correlation phase, fine tuning is performed
across the transmit and receive signal paths within the RF front end. Tis stage compensates for any residual phase mismatches introduced by analogue propagation delays, ensuring consistent timing across all RF channels.
Digital signal processing coherency: Finally, the Apollo MxFE system’s hardened DSP numerically controlled oscillator (NCO) phase shiſters are used to maintain coherent digital phase alignment across all data paths. Tis ensures that the system preserves phase coherency for beam forming and other multi-channel DSP functions, even aſter the physical and calibration based spur suppression stages.
Initial characterisation Initial system characterisation revealed that the SFDR was
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