A Countermeasure to Frequency Shift of Transmitter for Human Body Communication according to Battery Output Voltage Drop

In this paper, an operating frequency shift of the HBC transmitter according to the battery output voltage decreases was analyzed, and an appropriate operating frequency configuration for the HBC transmitter to minimize performance degradation was proposed. The operating frequency shift was measured as 30ppm with the supply voltage range from 3.0V to 2.1V. A frequency calibration was applied to the HBC transmitter to satisfy the CDR lock range that was measured for five HBC receiver samples.