[2] KIM I, BHAGAT Y A, HOMER J, et al. Multimodal analog front end for wearable bio-sensors [J]. IEEE Sensors J, 2016, 16(24): 8784-8791.
[3] TSIVIDIS Y. Continuous-time digital signal processing [J]. Elec Lett, 2003, 39(21): 1551-1552.
[4] LI Y J, ZHAO D, SERDIJN W A. A sub-microwatt asynchronous level-crossing ADC for biomedical applications [J]. IEEE Trans Biomed Circ Syst, 2013, 7(2): 149-157.
[5] LI Y J, MANSANO ANDRE L, YUAN Y, et al. An ECG recording front-end with continuous-time level-crossing sampling [J]. IEEE Trans Biomed Circ Syst, 2014, 8(5): 626-635.
[6] UDUPA S S, SUSHMA P S, CHAITHRA. ECG analog front-end in 180 nm CMOS technology [C]// ICICICT. Kerala, India. 2017: 327-330.
[9] TANG W, OSMAN A, KIM D, et al. Continuous time level crossing sampling adc for bio-potential recording systems [J]. IEEE Trans Biomed Circ Syst I: Regu Pap, 2013, 60(6): 1407-1418.
[10] WELTIN-WU C, TSIVIDIS Y. An event-driven clockless level-crossing ADC with signal-dependent adaptive resolution [J]. IEEE J Sol Sta Circ, 2013, 48(9): 2180-2190.