A Reference-Less All-Digital Transceiver for Human Body Channel Communication

In this paper, a reference-less all-digital wideband signaling (WBS) transceiver for body chancel communication (BCC) is presented. In the transmitter part, data are encoded in NRZI format, and the bit stuffer is used to increase the data transitions. In the receiver part, the received signals are amplified and restored to digital waveforms with analog frontend circuits. Then, the proposed reference-less all-digital clock and data recovery circuit (ADCDR) can recover the data. The proposed ADCDR can quickly compensate for the phase error. Thus, the proposed ADCDR can tolerate large data jitter and can still correctly recover the data. The automatically tracking gain calibration method is proposed to calculate the suitable gain value for the proposed ADCDR under process, voltage, and temperature (PVT) variations. The proposed all-digital WBS transceiver was implemented in TSMC 90nm CMOS process with standard cells. The data rate of the proposed transceiver ranges from 1 Mb/s to 20 Mb/s, and the power consumption is 5.5 mW at 20 Mb/s. In addition, the bit error rate is < 10(-8) at 20 Mb/s and the energy per bit is 0.275 nJ/b.