Low Noise

This paper introduces an open-source active high-precision signal amplifier designed for enhancing biodata acquisition, specifically focusing on EEG signals. The compact device, with a diameter of 18 mm, seamlessly integrates electronics, signal processing, and meticulous design considerations. Incorporated within the single board are circuits for low-noise amplification, an analog interface equipped with bandpass filters, and an integrated ADC for precise digitization. A comprehensive evaluation of signal quality has been conducted, encompassing aspects such as noise levels, electrode bias tolerance, and common mode rejection ratio. To facilitate this evaluation, the widely recognized Silver Chloride electrode (Ag/AgCl) has been employed. Additionally, this paper delves into an extensive discussion concerning diverse sources of noise, along with strategies to curtail input noise, and minimize noise originating from electrodes and amplifiers. Leveraging the substantial advancements achieved in the design of dry contact electrodes, this specific device is poised to carve a notable niche in the realm of brain-computer interface.

The Weak Equivalence Principle is at the basis of General Relativity and for this reason it is very important that its validity be experimentally verified as accurately as possible. The best experimental results have been obtained with test masses of different composition suspended on slowly rotating torsion balances. The rotation of the balance is crucial to up-convert the signal (which is DC in the field of the Earth and at the diurnal frequency in the field of the Sun) to higher frequency where both electronics and thermal noise are lower. Inside a spacecraft orbiting the Earth at low altitude test masses suspended similarly to a torsion balance are subject to a driving acceleration signal from the Earth about 3 orders of magnitude stronger and can therefore significantly improve ground based results. The proposed GG space experiment has the additional advantage of a rotation frequency much higher than that of ground balances, with consequent lower electronics and thermal noise. ...

In this paper we present a 5 spectrum TDI image sensor which is manufactured with a modified 1P6M CMOS process. Concept of CCD in CMOS with 3.5um pixel pitch has been verified. Design, characterization method and results will be addressed. Introduction TDI applications used to be dominated by CCDs because of its intrinsic charge transfer in array. Although there are many benefits in CMOS process such as low power, high integration, etc. we hardly see products for TDI processed with CMOS. Past works on TDI in CMOS can be categorized in two directions, with one working on signal summation in readout circuits [1-2] and the others on charge domain transfer in array [3-4]. Developments are shifting in the direction of charge domain transfer because it is noise free for signal adding while in circuit level, the noise will increase. We report in this paper a five band TDI image sensor with charge domain summation in CMOS process (CCD in CMOS). The middle band (P Band) is designed with 3.5u...

Recent advances in the development of silicon photodetectors working in the Geiger mode (SiPM), open new perspectives in space-based or balloon-borne calorimetry. However, present SiPM devices suffer from a number of limitations, including the instrinsic dynamic range of the photodetector and its operational stability, that have to be overcome in view of their utilization in ionization calorimetry. Test results will be presented on the readout performance of a SiPM prototype, optically coupled to scintillating fibers, and connected to low-noise front-end electronics with large dynamic range.

To take advantage of the astrophysical potential of Gamma-Ray Bursts (GRBs), Chinese and French astrophysicists have engaged the SVOM mission (Space-based multi-band astronomical Variable Objects Monitor). Major advances in GRB studies resulting from the synergy between space and ground observations, the SVOM mission implements space and ground instrumentation. The scientific objectives of the mission put a special emphasis on two categories of GRBs: very distant GRBs at z$>$5 which constitute exceptional cosmological probes, and faint/soft nearby GRBs which allow probing the nature of the progenitors and the physics at work in the explosion. These goals have a major impact on the design of the mission: the on-board hard X-ray imager is sensitive down to 4 keV and computes on line image and rate triggers, and the follow-up telescopes on the ground are sensitive in the NIR. At the beginning of the next decade, SVOM will be the main provider of GRB positions and spectral parameters...

Seismoelectric and seismomagnetic fields generated by seismic waves in fluid-saturated fractured borehole models are experimentally investigated with an electrode and a Hall-effect sensor. In a borehole with a horizontal fracture, the Stoneley and flexural waves induce seismoelectric and seismomagnetic fields on the borehole wall and an electromagnetic wave propagating at light speed at the horizontal fracture. In a borehole with a vertical fracture, the acoustic field generated by a monopole or dipole source is similar to that in a borehole without a vertical fracture. However, the acoustic wave propagating along the vertical fracture induces seismoelectric and seismomagnetic fields, whose apparent velocities are equal to that of a Stoneley wave. Experimental results show that two different kinds of electric and magnetic fields are generated by acoustic waves in borehole models with horizontal and/or vertical fractures. One is an electromagnetic wave propagating with light speed. T...

In this work, a new ring voltage controlled oscillator with a two cross coupled load PMOS transistors is proposed. The proposed method preserves the maximum frequency of the VCO unaffected which leads to improvement in phase noise and the power consumption of VCO oscillators. The proposed ring oscillator implemented in 0.18μm CMOS shows the worse phase noise of -108 dBc/Hz at 10MHz offset, tuning range of 140.7%, while dissipating a maximum power consumption of 9 mW from 1.8 V supply. Keywords— Ring oscillators, VCO, tuning range, phase noise, cross coupled PMOS transistors.

We designed, built, tested, and operated on-orbit a set of space-qualified electronics to (a) provide high-bandwidth and low-noise flux-locked-loop operation of four SQUID detectors, (b) regulate the temperature of the SQUIDs to better than 5 $\mu $K rms, and (c) digitize and provide ...