Naslov
An Energy Efficient Multi-User Asynchronous Wireless Transmitter for Biomedical Signal Acquisition

Autori
Matic, Tomislav ; Sneler, Leon ; Herceg, Marijan

Izvornik
IEEE Transactions on Biomedical Circuits and Systems (1932-4545) 13 (2019), 4; 619-630

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Wireless communication , Transmitters , Wireless sensor networks , Encoding , Monitoring , Sensors , Delays

Sažetak
The paper presents a novel transmitter architecture for short-range asynchronous wireless communication, applicable to simultaneous multi-user wireless acquisition of biological signals. The analog signal, provided from an analog biosensor, is transformed to time information using an Integral Pulse Frequency Modulator (IPFM) as a Time-Encoding Machine (TEM). The IPFM generates a time- encoded unipolar pulse train, maintaining the linear dependence of the output pulse distance on analog input voltage. The system enables continuous acquisition of the signals from multiple sensors in which each transmitter has unique feedback loop delay used for multiuser coding. IPFM pulses trigger the Impulse Radio Ultra-Wideband (IR-UWB) pulse generator directly, providing two Ultra-Wideband (UWB) pulses per each IPFM pulse. Due to the lack of internal clock signal and microprocessor-free multiuser coding, the circuitry satisfies the requirements of multi-user coding energy efficiency and size reduction, which are crucial demands in biomedical applications. The proposed Time-Encoded UWB (TE-UWB) transmitter is implemented in 0.18 μm CMOS technology. Measurement results of the IPFM transfer function for input voltage ranging from 0.15 V to 1.5 V are presented, providing the dependence of the IPFM pulse time distance on analog input voltage and power consumption dependence on the input voltage level. For continuous monitoring operation total power consumption of the transmitter circuitry for the maximum input voltage is 10.8 μW, while for the lowest input voltage it increases to 40.48 μW. The circuit occupies 0.14 mm $^2$.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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