Experimental Clock Calibration on a Crystal-Free Mote-on-a-Chip
Résumé
The elimination of the off-chip frequency reference,typically a crystal oscillator, would bring important benefits in terms of size, price and energy efficiency to IEEE802.15.4compliant radios and systems-on-chip. The stability of on-chip oscillators is orders of magnitude worse than that of a crystal.It is known that as the temperature changes, they can drift more than50ppm/◦C. This paper presents the result of an extensive experimental study. First, we propose mechanisms for crystal-free radios to be able to track an IEEE802.15.4 join proxy, calibrate the on-chip oscillators and maintain calibration against temperature changes. Then, we implement the resulting algorithms on a crystal-free platform and present the results of an experimental validation. We show that our approach is able to track a crystal-based IEEE802.15.4-compliant join proxy and maintain the requested radio frequency stability of±40ppm, even when subject to temperature variation of2◦C/min.
| Origine | Fichiers produits par l'(les) auteur(s) |
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