{'fraction_non_alphanumeric': 0.02017543859649123, 'fraction_numerical': 0.013157894736842105, 'mean_word_length': 5.832335329341317, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Energy-efficient resonant BFSK MICS transmitter with fast-settling dual-loop adaptive frequency locking

A digitally controlled resonant tank oscillator with loop antenna radiating inductor offers high energy efficiency in BFSK transmission, however suffers from frequency drift. Here we present a fast-settling adaptive digital architecture for dual-loop frequency locking of a BFSK transmitter. The method uses interleaved frequency-locked loops (FLL) that allow fast and energy-efficient direct digitally controlled oscillator (DCO) frequency modulation at a data rate exceeding the settling time of the frequency adaptation, while maintaining frequency regulation. The fully digital FLL architecture retains the dual-loop adapted states between transmission bursts, allowing for energy-efficient low duty cycle transmissions with minimal or no settling transient at the beginning of a transmission burst. Analysis and simulation results are presented of the architecture operating in the 402–405MHz MICS band for biomedical applications, indicating locking at 130 kHz frequency resolution at 115 µs settling for 125 kbps BFSK telemetry.