9 research outputs found
Study on Zero-Crossing-Based ADCs for Smart Dust Applications
No full textThe smart dust concept is a fairly recent phenomenon to engineering. It assumes monitoring of a real natural environment in which motes or smart dust machines swarm in collective and coordinate information among themselves and/or to a backend control platform. In analog mixed signal field work on such devices is gaining momentum such that it is conceived to be one of the emerging fields in technology, and work was only possible once the technology for fabrication touched the nanoscale regions. Smart dust network involves remote devices connected in a hive sensing burst type datum signals from the environment and relaying information amongst themselves in an energy efficient manner to coordinate an appropriate response to a detected stimulus. The project presumed a RF based communication strategy for coordination amongst the devices through a wireless medium. That is less susceptible to stringent requirements of LOS and a base band processing system that comprised of an environment sensor, an AFE module, an ADC, a DSP and a DAC. Essentially a 10 bit, 2 Mega Hertz MHz pipelined ADC implemented in a STM 65nm technology. The ADC benefits the smart dust device in allowing it to process data in an energy efficient way and also focusing on reduced complexity as itsdesign feature. While it differs in the other ADC of the system by operating at a higher frequency and assuming a different design philosophy assuming a coherent system sensitive to a clock. The thesis work assumes that various features ofenergy harvesting, regulation and power management present in the smart dustmote would enable the system to contain such a diverse ADC. The ADCs output digital datum would be compatible to the rest of the design modules consisting mainly of DSP sections. The ADC novelty is based on the fact that it removes the necessity of employing a high power consuming OpAmp whose design parameters become more complex as technology scales to the nanoscale era and further down. A systematic, bottom up, test driven approach to design is utilized and various behaviours of the system are captured in Cadence design environment with verilogto layout models and MATLAB and Simulink models
Ambient Light Suppression in Visible Light Transceivers: A Review
No full textVisible light communication has emerged as a promising complementary technology to enable communication between vehicles and traffic infrastructure. However, the visible light transceivers suffer from optical interference and ambient light saturation which severely affect the reception of the optical signal. In this paper, we present an overview of background light suppression techniques and analyse their merits and demerits. Mainly, the practical applicability of each technique for the integrated photodiode-based visible light receivers in automotive applications are discussed in this paper.</p
A Laser Doppler Blood Flow Measurement System With a 151.4 dBΩ Gain and 0.05% Nonlinearity for PAD Patients
No full textThis article presents a compact blood flow measurement system exploiting the Doppler effect and photocurrent sensing technique for wearable health monitoring. Specifically, it helps the patients suffering from peripheral artery disease (PAD) to monitor the blood flow continuously without involving a physician or medical expert. The system prototype integrates a laser diode, a photodiode, and an analog front-end (AFE) on a 54 mm ×64 mm three-layer PCB using discrete components for proof of concept. The front-end is designed with two output modes providing simultaneous current-to-voltage and current-to-frequency conversion without requiring an external clock source. Moreover, this system does not require optical filters or fibers, dynamic artifacts are therefore significantly reduced. Drawing 33 mA current from a 3.3-V supply, the developed system offers a transimpedance gain of 151.4 dB Ω for the voltage mode output. For the frequency output, a nonlinearity of 0.05% is achieved.Other InformationPublished in: IEEE Sensors JournalLicense: https://creativecommons.org/licenses/by/4.0/See article on publisher's website: https://dx.doi.org/10.1109/jsen.2022.3180927</p
A high frequency divide-by-odd number CMOS LC injection-locked frequency divider
No full textNumerous circuit topologies have been proposed for divide-by-ρ injection-locked frequency dividers (ILFDs), most of which have been optimized for division by even numbers, especially divide-by-2. It has been more difficult to realize division by odd numbers, such as divide-by-3. In this paper we present simulations of an RF CMOS ILFD that can operate equally well in both divide-by-2 and divide-by-3 modes. The ILFD is based on a cross-coupled CMOS LC oscillator with direct injection and an auxiliary injection path. The paper presents two variants of the circuit architecture and Cadence simulations in the multi-GHz frequency range using a standard TSMC 65 nm CMOS process design kit. © 2013 Springer Science+Business Media New York
Joint Network Admission Control, Mode Selection and Power Allocation in Energy Harvesting enabled D2D Communication
No full textA novel synthesis of solid-solid (SSMePCM) by in situ polymerization
No full textIn this research solid-solid microencapsulated phase change material (SSMePCM) with high thermal energy storage density (177.6 Jg/1) was synthesized successfully by in situ polymerization using biodegradable natural polymer chitosan as shell and polyethylene glycol (PEG-1000) as core. The morphology, chemical structure and thermal properties were characterized by optical microscopy (OM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The results show that the obtained SSMePCM dispersed individually with a spherical shape. Author (s) recommends the all set thermal and chemically steady microcapsule for thermal energy storage purposes as novel synthesized SSMePCM with latent heat storage capacities.</p
Value of intraoperative computed tomography in intraaxial brain tumour surgery: a systematic review
No full textReal-time intraoperative imaging with neuronavigation is a valuable adjunct in the surgical management of intra-axial brain tumours. While intraoperative magnetic resonance imaging (iMRI) is the gold standard, recent advances in technology have explored the utility of intraoperative computed tomography (iCT) as an alternative. A systematic review was conducted by searching multiple databases, including MEDLINE, PubMed, Scopus, Cochrane Library, and Web of Science, for studies published from 1982 to 2024. Studies that evaluated the use of iCT in intra-axial brain tumour surgeries and reported on outcomes such as the extent of tumour resection (EOTR), residual tumour detection, and postoperative complications were included. Thirteen studies met the inclusion criteria. Overall, recent improvements in iCT’s soft tissue imaging quality have increased its utility in intra-axial brain tumour surgeries. iCT was found to improve tumour resection accuracy in some instances, helping neurosurgeons detect residual tumours and refine surgical strategies. However, conclusions about its impact on long-term outcomes are limited by the lack of data on molecular tumour characteristics and adjuvant therapies. Further high-quality prospective work is needed to validate the role of iCT in improving key outcome parameters in neuro-oncology. Until then, iCT remains an adjunct whose use can be considered in select cases. Continued research on iCT is warranted to determine further indications in intra-axial brain tumour surgery
