All-Digital Galvanically-Coupled BCC Receiver Resilient to Frequency Misalignment.

Area of Science:

• Wearable technology
• Biomedical engineering
• Integrated circuit design

Background:

• Miniaturization of wearable devices is crucial for reducing user load.
• Conventional wireless communication components like antennas and crystals are bulky.
• Galvanically-coupled body channel communication (GC-BCC) offers a size advantage by reusing electrodes.

Purpose of the Study:

• To develop a compact GC-BCC receiver immune to frequency misalignments.
• To enable smaller wearable devices by removing the need for crystals.
• To improve the robustness of body channel communication systems.

Main Methods:

• Implementation of a low-power all-digital Gaussian frequency shift keying (GFSK) demodulator.
• Development of a carrier tracking technique for automatic carrier frequency misalignment adaptation.
• Proposal of a circle-index clock-data recovery (CDR) circuit to handle clock frequency inaccuracies.

Main Results:

• The proposed GC-BCC receiver is implemented using 0.18 μm CMOS technology.
• The circuit operates at 200 kHz with a BFSK/GFSK modulation index of 1.0.
• Measured power consumption is 0.53 mA at 100 kb/s data rate.
• The receiver tolerates significant carrier and clock frequency errors while maintaining a low bit error rate (BER < 0.1%).

Conclusions:

• The developed GC-BCC receiver effectively addresses the miniaturization challenge for wearable devices.
• The integrated carrier tracking and CDR circuits provide immunity to frequency drifts.
• This technology paves the way for smaller, more integrated body-worn communication systems.