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A high-precision and temperature insensitive longrange distance measurement (DM) based on frequency detection is proposed and experimentally demonstrated. Two optoelectronic oscillators (OEOs) are grouped into a cross-referencing structure by Dense Wavelength Division Multiplexing (DWDM), which can greatly increase the measurement accuracy by reducing the influence of the environment such as temperature...
The aim of this work is to study the feasibility of using the modulated frequency selective surface (FSS) as a semi-passive tag for body sensing applications at 2.45 GHz ISM band. Two prototypes are presented: a breathing sensor and a skin thermometer. The breathing sensor measures the change of the airflow temperature that is produced during respiration. The core of this sensor is a negative temperature...
We developed a compact sensor module for hydroponics that measures the nutrient concentration and water level using simple oscillator circuits. Oscillation frequencies are measured and are found to change in response to the resistance and capacitance between metal wires on a printed circuit board submerged in liquid fertilizer. A microprocessor is mounted on the sensor board for measurement and communication...
Partial shading on a photovoltaic (PV) string will lead to PV characteristic, exhibiting multiple peaks. Conventional methods such as P&O method may not track the Global Maximum Point (GMP). Researchers have utilized meta heuristic approaches to track the GMP. Recently Simulated Annealing (SA) method has also been adapted for Maximum Power Point Tracking (MPPT) because of its simplicity and effectiveness...
Spurious oscillations in the low frequency region (below 100kHz) were investigated in InGaP/GaAs HBT devices and circuits. These low frequency oscillations (LFOs) are predominantly activated by the field across the semi-insulating GaAs substrate located between the subcollector and backside metal (of an emitter-up device). Several experiments were conducted to control and eliminate LFOs by floating...
This paper proposes a new synthesizable oscillator-based temperature sensor with minimal footprint for use in contemporary Xilinx FPGA devices. In contrast to previously published ring-oscillator architectures, based on inverters mapped onto single LUTs, the proposed oscillator uses an asynchronous Gray-coded 4-bit counter requiring only two 6-input LUTs. Due to its reduced hardware requirements,...
The proposed digital sensor measures both temperature and voltage simultaneously in field. The sensor is ring oscillator (RO)-based and its design is fully digital. Its measurement time is shorter than the conventional analog sensors' and it can be placed at any place such as the boundary of a CPU core, GPU core, or Memory. This paper investigates the accuracy of the sensor derived from reduction...
The parallel and transverse magnetoresistance in InSb and GaSb whiskers doped with tin and tellurium, respectively, were investigated in the temperature range 4.2–77 K and magnetic field 0–14 T. Shubnikov-de Haas magnetoresistance oscillations were revealed at low temperatures for both semiconductor materials with impurity concentration near the metal-insulator transition. The following parameters...
The research investigates the peculiarities of building high-stable quartz crystal oscillator (XO) with digital compensation of temperature frequency instability as one of the main destabilizing factors, which influence the accuracy characteristics of XO. The rise of stability of frequency oscillations of XO is reached with the help of more accurate compensation of temperature influences on the basis...
This paper presents a relaxation oscillator that utilizes a supply-stabilized pico-powered voltage and current reference (VCRG) to charge and reset a chopped pair of MIM capacitors at sub-nW power levels. Specifically, a temperature- and line-stabilized reference voltage is generated via a 4-transistor (4T) self-regulated structure, the output of which is used to bias a temperature-compensated gate-leakage...
In this work, an improved topology of a relaxation oscillator is proposed, dealing with the non-idealities of the comparator stage. The oscillator test chips, manufactured in 0.35-μm CMOS process, have the nominal frequency of 1 MHz and typical power consumption of 210 μW. The area of the oscillator core is 0.04 mm2. The measured temperature variation of the output frequency is ±0.4% in the temperature...
Amorphous thin films are used as components of acoustic resonators because they could control temperature coefficient of resonator. Because elastic constants of thin films are often different from those of bulk materials, the direct measurement of sound velocity and temperature coefficient of velocity (TCV) for individual thin films becomes important in designing resonators. Because The TCV of amorphous...
We show here that temperature influences single microbubble dynamics by changing lipid shell viscoelastic properties. A newly developed photoacoustic measurement technique drove individual microbubbles into small-amplitude oscillations through ultrasound waves generated by the absorption of an amplitude-modulated laser. Forward light scattering was used to detect bubble oscillations as the modulation...
The first fully integrated oven-controlled temperature compensation system with the transformer coupled Colpitts oscillator is developed by 65nm CMOS tech. This work achieves ±1.55ppm frequency stability over the 85°C temperature range which can be used for the GPS application (<2ppm). An integrated heater in the FBAR chip consumes 14mW power at maximum. The temperature resolution of TDC is 150uK,...
A 300 GHz pulse gyrotron has been developed for collective Thomson scattering diagnostics in the Large Helical Device with a careful design consideration. Single-mode oscillation of more than 320 kW was attained. The frequency spectrum was very narrow and stable across the pulse width up to 80 μs. No parasitic mode was observed during the whole pulse width including the turn-on and turn-off phases...
A system clock is implemented with a 2.52 GHz MEMS-based oscillator, divider, temperature sensor, digital PLL, and active temperature compensation to generate a 48 MHz frequency reference with ±10 ppm stability from −40°C to 105°C. An on-chip 32 kHz RC oscillator is also periodically calibrated by this reference clock to achieve ±500 ppm accuracy, allowing it to be used as the wireless node sleep...
Piezoresistive sensing has been regarded as an effective transduction method in MEMS resonator researches and piezoresistive micromechanical oscillators are therefore of great interests. The induced joule heating in the piezoresistive sensing, however, has a strong effect on the performance of the device. In this work, a micromechanical double ended tuning fork (DETF) based piezoresistive oscillator...
This paper presents the implementation of an active fiber optical-delay stabilization system in an optoelectronic oscillator. The primary use of the system is to stabilize optical point-to-point fiber links for synchronization purposes; however, the system can also be efficiently used as a stable optical delay line in an opto-electronic oscillator. By using a multipurpose optical delay stabilization...
A GPS-disciplined oscillator (GPSDO) provides a cost-effective alternative to a primary clock such as a cesium-beam atomic clock. A rubidium (Rb) atomic oscillator is usually employed in a GPSDO as a holdover clock where maintaining the most accurate time is required during an extended absence of GPS signals. A commercially available Chip-Scale Atomic Clock (CSAC) offers a comparable long-term stability...
We report on a 32-MHz quartz TCXO fully integrated with commercial CMOS electronics and vacuum packaged at wafer level using a low-temperature MEMS-after quartz process. The novel quartz resonator design provides for stress isolation from the CMOS substrate thereby yielding classical AT-cut f/T profiles and low hysteresis which can be compensated to < ± 0.2 ppm over temperature using on-chip third-order...
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