Search

An energy-efficient PLL-based FSK transmitter is reported in this work. The PLL output signal is manipulated by a sigma-delta modulated phase rotator, whose output frequency is controlled by the input data, to produce FSK signals. Since the data is applied outside the PLL, the frequency modulation characteristics are no longer constrained by the PLL loop. Fabricated in a 0.18-mum CMOS process, the whole transmitter draws 13 mA from a 1.5-V supply. With a 1.5-Mbps data rate, the transmitter achieves an energy efficiency of 13 nJ/bit, and delivers an output power of -9 dBm.

An asymmetrical wireless interface and transceiver designed for implanted medical image applications are reported. The proposed system operated at the 402-405 MHz MICS (medical implantable communication system) band, and it utilizes different modulation schemes for uplink and downlink to lower power consumption and reduce circuit implementation complexity. A high data rate (524 kbps within 300-kHz channel and maximum 1.5 Mbps) and low-power (12.7 mW) direct-modulation FSK transmitter is proposed for medical image transmission, and a low-power (3.3 mW) superregenerative OOK receiver is adopted for command receiving. The wireless interface design considerations and key circuit realizations are presented in this paper.

Intra-cortical extracellular neural sensing is being rapidly and widely applied in several clinical research and brain-computer interfaces (BCIs), as the number of sensing channels continues to double every 6 years. By distributing multiple high-density extracellular micro-electrode arrays (MEAs) in vivo across the brain, each with 1000's of sensing channels, neuroscientists have begun to map the correlation of neuronal activity across different brain regions, with single-neuron precision [1]. Since each neural sensing channel typically samples at 20 to 50kS/s with a > 10b ADC, multiple MEAs demand a data transfer rate up to Gb/s [2]. However, these BCIs are severely hindered in many clinical uses due to the lack of a high-data-rate and miniature-wireless-telemetry solution that can be implanted below the scalp, i.e., transcutaneously (Fig. 24.2.1). The area of the wireless telemetry module should be miniaturized to ~3cm2 due to neurosurgical implantation constraints. A transmission range up to 10cm is highly desirable, in order to improve the reliability of the wireless link against e.g., antenna misalignment, etc. Finally, the power consumption of the wireless telemetry should be limited to ~10mW to minimize thermal flux from the module's surface area, avoiding excessive tissue heating. Most of the conventional transcutaneous wireless telemetry systems adopt inductive coupling, but the data-rate is limited to a few Mb/s. A near-infrared (NIR) optical transcutaneous TX using a vertical-cavity-surface-emitting laser (VCSEL) [2] demonstrated a data-rate up to 300Mb/s but suffers from a limited transmission range (4mm) and requires a sub-mm precise alignment between the implant TX and a wearable RX. Impulse-radio UWB (IR-UWB) is promising for the targeted requirements [3]–[5].

A digital Linear Discrete Frequency Modulated Continuous Wave (LD-FMCW) radar is analyzed and demonstrated for multi-people tracking and vital signs monitoring. Waveform analysis, simulations, and experimental results are presented to validate the proposed radar architecture.