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With the growing number of wearable devices and applications, there is an increasing need for a flexible body channel communication (BCC) system that supports both scalable data rate and low power operation. In this paper, a highly flexible frequency-selective digital transmission (FSDT) transmitter that supports both data scalability and low power operation with the aid of two novel implementation methods is presented. In an FSDT system, data rate is limited by the number of Walsh spreading codes available for use in the optimal body channel band of 40–80 MHz. The first method overcomes this limitation by applying multi-level baseband coding scheme to a carrierless FSDT system to enhance the bandwidth efficiency and to support a data rate of 60 Mb/s within a 40-MHz bandwidth. The proposed multi-level coded FSDT system achieves six times higher data rate as compared to other BCC systems. The second novel implementation method lies in the use of harmonic frequencies of a Walsh encoded FSDT system that allows the BCC system to operate in the optimal channel bandwidth between 40–80 MHz with half the clock frequency. Halving the clock frequency results in a power consumption reduction of 32%. The transmitter was fabricated in a 65-nm CMOS process. It occupies a core area of 0.24\,\times\,0.3 mm^2. When operating under a 60-Mb/s data-rate mode, the transmitter consumes 1.85 mW and it consumes only 1.26 mW when operating under a 5-Mb/s data-rate mode. [ABSTRACT FROM AUTHOR]

Monitoring blood flow rate inside prosthetic vascular grafts enables an early detection of the graft degradation, followed by the timely intervention and prevention of the graft failure. This paper presents an inductively powered implantable blood flow sensor microsystem with bidirectional telemetry. The microsystem integrates silicon nanowire (SiNW) sensors with tunable piezoresistivity, an ultralow-power application-specific integrated circuit (ASIC), and two miniature coils that are coupled with a larger coil in an external monitoring unit to form a passive wireless link. Operating at 13.56-MHz carrier frequency, the implantable microsystem receives power and command from the external unit and backscatters digitized sensor readout through the coupling coils. The ASIC fabricated in 0.18-μm CMOS process occupies an active area of 1.5 × 1.78 mm^2 and consumes 21.6 μW only. The sensors based on the SiNW and diaphragm structure provide a gauge factor higher than 300 when a small negative tuning voltage (−0.5–0 V) is applied. The measured performance of the pressure sensor and ASIC has demonstrated 0.176 mmHg/√Hz sensing resolution. [ABSTRACT FROM PUBLISHER]

Individuals with tetraplegia lack independent mobility, making them highly dependent on others to move from one place to another. Here, we describe how two macaques were able to use a wireless integrated system to control a robotic platform, over which they were sitting, to achieve independent mobility using the neuronal activity in their motor cortices. The activity of populations of single neurons was recorded using multiple electrode arrays implanted in the arm region of primary motor cortex, and decoded to achieve brain control of the platform. We found that free-running brain control of the platform (which was not equipped with any machine intelligence) was fast and accurate, resembling the performance achieved using joystick control. The decoding algorithms can be trained in the absence of joystick movements, as would be required for use by tetraplegic individuals, demonstrating that the non-human primate model is a good pre-clinical model for developing such a cortically-controlled movement prosthetic. Interestingly, we found that the response properties of some neurons differed greatly depending on the mode of control (joystick or brain control), suggesting different roles for these neurons in encoding movement intention and movement execution. These results demonstrate that independent mobility can be achieved without first training on prescribed motor movements, opening the door for the implementation of this technology in persons with tetraplegia. [ABSTRACT FROM AUTHOR]

Body channel communication (BCC) integrated circuits for emerging wireless body area network multimedia applications call for the need of high-speed inter-device data communication at ultra-low-power consumption and smaller device footprint. In this paper, a novel low-power injection-locking-based clock-recovery circuit (CRC) is proposed for BCC transceivers that employ multilevel direct digital signaling for high data rates. The CRC utilizes transition detection for generating pulses from transmitted digital data and injects them directly into the VCO to recover the clock. The pulse-based direct injection-locking architecture achieves instantaneous clock recovery from random multilevel data with a sensitivity of up to -43 dBm, and eliminates the need for a reference crystal used in conventional phase-locked-loop-based CRC circuits. Measured results verify that the proposed CRC achieves clock recovery for two- and three-level signals for data rates up to 160 Mb/s. Implemented in 65-nm CMOS technology, the CRC consumes 0.84 mW with a footprint of 0.12 \ mm^2. [ABSTRACT FROM AUTHOR]