A low-complexity and high-frequency ASIC transceiver for an ultrasound imaging system.

This article presents a high-frequency application-specific integrated circuit (ASIC) transceiver for an ultrasound imaging system designed with a focus on low complexity. To simplify the design, it employs a conventional Class-D power amplifier structure for the transmitter (TX) and a resistive feedback transimpedance amplifier (TIA), which consists of a common-source amplifier followed by a source follower for the receiver (RX). Through careful optimization, the RX achieves a measured transimpedance gain of 90 dBΩ and an input-referred noise of 5.

Efficient Distributed Wireless Power Transfer System for Multiple Wearable Sensors through Textile Coil Array.

When it is necessary to detect various physiological signals of the human body, clothing embroidered with near-field effect patterns can be used as a long-term power supply medium to supply power to long-distance transmitters and receivers to form a wireless power supply system. The proposed system uses an optimized parallel circuit to achieve a power transfer efficiency of more than five times higher than that of the existing series circuit. The power transfer efficiency of simultaneously supplying energy to multiple sensors is increased higher than five times and even more when only one sensor is coupled.

Circuits on miniaturized ultrasound imaging system-on-a-chip: a review.

Trends of medical system move from a traditional in-person visit to virtual healthcare increases demands on point-of-care devices. Because ultrasound (US) is non-invasive, the demands highlight US imaging among other imaging modalities. Thanks to the development of US transducer technology, miniaturized US with application-specific integrated circuits (ASIC) have been researched.

Highly Integrated Guidewire Ultrasound Imaging System-on-a-Chip.

In this article, we present a highly integrated guidewire ultrasound (US) imaging system-on-a-chip (GUISoC) for vascular imaging. The SoC consists of a 16-channel US transmitter (Tx) and receiver (Rx) electronics, on-chip power management IC (PMIC), and quadrature sampler. Using a synthetic aperture imaging algorithm, a Tx/Rx pair, connected to capacitive micromachined ultrasound transducers (CMUTs), can be activated at any time.

An Impulse Radio PWM-Based Wireless Data Acquisition Sensor Interface.

A sensor interface circuit based on impulse radio pulse width modulation (IR-PWM) is presented for low power and high throughput wireless data acquisition systems (wDAQ) with extreme size and power constraints. Two triple-slope analog-to-time converters (ATC) convert two analog signals, each up to 5 MHz in bandwidth, into PWM signals, and an impulse radio (IR) transmitted (Tx) with an all-digital power amplifier (PA) combines them while preserving the timing information by transmitting impulses at the PWM rising and falling edges. On the receiver (Rx) side, an RF-LNA followed by an envelope detector recovers the incoming impulses, and a T-flipflop reverts the impulse sequence back to PWM to be digitized by a time-to-digital converter (TDC).

Feasibility Study on Active Back Telemetry and Power Transmission Through an Inductive Link for Millimeter-Sized Biomedical Implants.

This paper presents a feasibility study of wireless power and data transmission through an inductive link to a 1-mm implant, to be used as a free-floating neural probe, distributed across a brain area of interest. The proposed structure utilizes a four-coil inductive link for back telemetry, shared with a three-coil link for wireless power transmission. We propose a design procedure for geometrical optimization of the inductive link in terms of power transmission efficiency (PTE) considering specific absorption rate and data rate.

Optimal Design of a Resonance-Based Voltage Boosting Rectifier for Wireless Power Transmission.

This paper presents the design procedure for a new multi-cycle resonance-based voltage boosting rectifier (MCRR) capable of delivering a desired amount of power to the load (PDL) at a designated high voltage (HV) through a loosely-coupled inductive link. This is achieved by shorting the receiver (Rx) LC-tank for several cycles to harvest and accumulate the wireless energy in the RX inductor before boosting the voltage by breaking the loop and transferring the energy to the load in a quarter cycle. By optimizing the geometries of the transmitter (Tx) and Rx coils and the number of cycles, , for energy harvesting, through an iterative design procedure, the MCRR can achieve the highest PDL under a given set of design constraints.

Towards a Reduced-Wire Interface for CMUT-Based Intravascular Ultrasound Imaging Systems.

Having intravascular ultrasound (IVUS) imaging capability on guide wires used in cardiovascular interventions may eliminate the need for separate IVUS catheters and expand the use of IVUS in a larger portion of the vasculature. High frequency capacitive micro machined ultrasonic transducer (CMUT) arrays should be integrated with interface electronics and placed on the guide wire for this purpose. Besides small size, this system-on-a-chip (SoC) front-end should connect to the back-end imaging system with a minimum number of wires to preserve the critical mechanical properties of the guide wire.

Toward a reduced-wire readout system for ultrasound imaging.

We present a system-on-a-chip (SoC) for use in high-frequency capacitive micromachined ultrasonic transducer (CMUT) imaging systems. This SoC consists of trans-impedance amplifiers (TIA), delay locked loop (DLL) based clock multiplier, quadrature sampler, and pulse width modulator (PWM). The SoC down converts RF echo signal to baseband by quadrature sampling which facilitates modulation.

Iron chelator-inducible expression system for Escherichia coli.

The PentC promoter of the entCEBA operon encoding enzymes for enterobactin biosynthesis in Escherichia coli is tightly regulated by the availability of iron in the culture medium. In iron-rich conditions, the PentC promoter activity is strongly repressed by the global transcription regulator Fur (ferric uptake regulator), which complexes with ferrous ions and binds to the Fur box 19-bp inverted repeat. In this study, we have constructed the expression vector pOS2 containing the PentC promoter and characterized its repression, induction, and modulation by quantifying the expression of the lacZ reporter gene encoding beta- galactosidase.