scholarly journals Apsu: a wireless multichannel receiver system for surface-NMR groundwater investigations

2018 ◽  
Author(s):  
Lichao Liu ◽  
Denys Grombacher ◽  
Esben Auken ◽  
Jakob Juul Larsen
Keyword(s):  
Data Acquisition ◽  
Dynamic Range ◽  
Dead Time ◽  
Signal To Noise Ratio ◽  
Noise Cancellation ◽  
Low Noise ◽  
Dipole Source ◽  
Central Unit ◽  
Long Distance ◽  
Receiver System

Abstract. Surface nuclear magnetic resonance (surface-NMR) has the potential to be an important geophysical method for groundwater investigations, but the technique suffers from poor signal-to-noise ratio (SNR) and long measurement times. We present a new wireless, multichannel surface-NMR receiver system (called Apsu) designed to improve SNR, field deployability and minimize instrument dead time. It is a distributed wireless system consisting of a central unit and independently operated data acquisition boxes each with three channels that measure either the NMR signal or noise for reference noise cancellation. Communication between the central unit and the data acquisition boxes is done through long distance WiFi and recordings are retrieved in real time. The receiver system employs differential coils with low-noise pre-amplifiers and high-resolution wide dynamic range acquisition boards. Each channel contains multi-stage amplifiers, short settling-time filters and two 24-bit analog-to-digital converters in dual-gain mode sampling at 31.25 kHz. The system timing is controlled by GPS clock and sample jitter between channels is less than 12 ns. Separated transmitter/receiver coils and continuous acquisition allow NMR signals to be measured with zero instrument dead time. In processed data, analog and digital filters causes an effective dead time of 4 ms. Synchronization with an independently operated transmitter system is done with a current probe monitoring the NMR excitation pulses. The noise density measured in a shorted-input test is 1.8 nV/√(Hz). We verify the accuracy of the receiver system with measurements of a magnetic dipole source and by comparing our NMR data with data obtained using an existing commercial instrument. The applicability of the system for reference noise cancellation is validated with field data.

scholarly journals Apsu: a wireless multichannel receiver system for surface nuclear magnetic resonance groundwater investigations

2019 ◽  
Vol 8 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Lichao Liu ◽  
Denys Grombacher ◽  
Esben Auken ◽  
Jakob Juul Larsen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Data Acquisition ◽  
Dead Time ◽  
Noise Cancellation ◽  
Low Noise ◽  
Central Unit ◽  
Long Distance ◽  
Receiver System ◽  
Nuclear Magnetic

Abstract. Surface nuclear magnetic resonance (surface NMR) has the potential to be an important geophysical method for groundwater investigations, but the technique suffers from a poor signal-to-noise ratio (SNR) and long measurement times. We present a new wireless, multichannel surface-NMR receiver system (called Apsu) designed to improve field deployability and minimize instrument dead time. It is a distributed wireless system consisting of a central unit and independently operated data acquisition boxes each with three channels that measure either the NMR signal or noise for reference noise cancellation. Communication between the central unit and the data acquisition boxes is done through long-distance Wi-Fi and recordings are retrieved in real time. The receiver system employs differential coils with low-noise preamplifiers and high-resolution wide dynamic-range acquisition boards. Each channel contains multistage amplifiers, short settling-time filters, and two 24 bit analog-to-digital converters in dual-gain mode sampling at 31.25 kHz. The system timing is controlled by GPS clock, and sample jitter between channels is less than 12 ns. Separated transmitter/receiver coils and continuous acquisition allow NMR signals to be measured with zero instrument dead time. In processed data, analog and digital filters cause an effective dead time of 5.8 ms including excitation current decay. Synchronization with an independently operated transmitter system is done with a current probe monitoring the NMR excitation pulses. The noise density measured in a shorted-input test is 1.8 nV Hz-1/2. We verify the accuracy of the receiver system with measurements of a magnetic dipole source and by comparing our NMR data with data obtained using an existing commercial instrument. The applicability of the system for reference noise cancellation is validated with field data.

scholarly journals The 1.3mm Full-Stokes Polarization System at CARMA

2015 ◽  
Vol 04 (01n02) ◽  
pp. 1550005 ◽  
Author(s):  
Charles L. H. Hull ◽  
Richard L. Plambeck
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Position Angle ◽  
Low Noise ◽  
Low Noise Amplifiers ◽  
Beam Polarization ◽  
Circular Polarizer ◽  
Angle Measurements ◽  
Millimeter Wavelengths ◽  
And Performance

The CARMA 1.3[Formula: see text]mm polarization system consists of dual-polarization receivers that are sensitive to right- (R) and left-circular (L) polarization, and a spectral-line correlator that measures all four cross polarizations ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]) on each of the 105 baselines connecting the 15 telescopes. Each receiver comprises a single feed horn, a waveguide circular polarizer, an orthomode transducer (OMT), two heterodyne mixers, and two low-noise amplifiers (LNAs), all mounted in a cryogenically cooled dewar. Here we review the basics of polarization observations, describe the construction and performance of key receiver components (circular polarizer, OMT, and mixers — but not the correlator), and discuss in detail the calibration of the system, particularly the calibration of the R–L phase offsets and the polarization leakage corrections. The absolute accuracy of polarization position angle measurements was checked by mapping the radial polarization pattern across the disk of Mars. Transferring the Mars calibration to the well-known polarization calibrator 3C286, we find a polarization position angle of [Formula: see text] for 3C286 at 225[Formula: see text]GHz, consistent with other observations at millimeter wavelengths. Finally, we consider what limitations in accuracy are expected due to the signal-to-noise ratio, dynamic range, and primary beam polarization.

scholarly journals Development of a new distributed hybrid seismic-electrical data acquisition station based on system–on-a-programmable-chip technology

2019 ◽  
Author(s):  
Qisheng Zhang ◽  
Wenhao Li ◽  
Feng Guo ◽  
Zhenzhong Yuan ◽  
Shuaiqing Qiao ◽  
...  
Keyword(s):  
Low Power ◽  
Data Acquisition ◽  
High Precision ◽  
Data Transmission ◽  
Dynamic Range ◽  
Low Voltage ◽  
Low Noise ◽  
Transmission Protocol ◽  
Control Board ◽  
Electrical Data

Abstract. In the past few decades, with the continuous advancement of technology, seismic-electrical instruments have developed rapidly. However, complex and harsh exploration environments have put forward higher requirements and severe challenges for traditional geophysical exploration methods and instruments. Therefore, it is extremely urgent to develop new high-precision exploration instruments and data acquisition systems. In this study, a new distributed seismic-electrical hybrid acquisition station is developed using system-on-a-programmable-chip (SoPC) technology. The acquisition station hardware includes an analog board and a main control board. The analog board uses a signal conditioning circuit and a 24-bit analog-to-digital converter (ADS1271) to achieve high-precision data acquisition, while the main control board uses a low-power SoPC chip to enable high-speed stable data transmission. Moreover, the data transmission protocol for the acquisition station was designed, an improved low-voltage differential signaling data transmission technology was independently developed, and a method to enhance the precision of synchronous acquisition was studied in depth. These key technologies, which were developed for the acquisition station, were integrated into the SoPC of the main control board. Testing results indicate that the synchronization precision of the acquisition station is better than 200 ns, and the maximum low-power data transmission speed is 16 Mbps along a 55 m cable. Simultaneously, the developed acquisition station has the advantages of low noise, large dynamic range, low power consumption, etc., and it can achieve high-precision hybrid acquisition of seismic-electrical data.

Design of MIRA, a low-noise pixelated ASIC for the readout of micro-channel plates

2022 ◽  
Vol 17 (01) ◽  
pp. C01047
Author(s):  
E. Fabbrica ◽  
M. Carminati ◽  
D. Butta ◽  
M. Uslenghi ◽  
M. Fiorini ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Count Rate ◽  
Dynamic Range ◽  
Dead Time ◽  
Uv Spectroscopy ◽  
Low Noise ◽  
Micro Channel ◽  
High Count ◽  
Processing Times ◽  
Channel Plate

Abstract We present the design of the first prototype of MIRA (MIcro-channel plate Readout ASIC) that has been designed to read out Micro-Channel Plates (MCP), in particular for UV spectroscopy. MIRA will be able to detect the cloud of electrons generated by each photon interacting with the MCP, sustaining high local and global count rates to fully exploit the MCP intrinsic dynamic range with low dead time. The main rationale that guided the electronics design is the reduction of the input Equivalent Noise Charge (ENC) in order to allow operations with lower MCP gain, thus improving its lifetime, crucial aspect for long missions in space. MIRA features two selectable analog processing times, 133 ns or 280 ns (i.e. fast mode or slow mode), granting a count rate per pixel of 100 kcps. Moreover, it shows an Equivalent Noise Charge ENC = 17 e r m s − . A spatial resolution of 35 μm and an operation with zero dead time, due to the readout, are targeted. The low noise, high count rate and high spatial resolution requirements are expected by keeping a compact pixel size (35 μm × 35 μm) for a total of 32 × 32 pixels in a 2 mm × 2 mm ASIC area. In this work, the ASIC design is described.

Design of Microwave LNA Based on Ladder Matching Networks for WiMAX Applications

2016 ◽  
Vol 6 (4) ◽  
pp. 1717
Author(s):  
Abu Bakar Ibrahim ◽  
Ahmad Zamzuri Mohamad Ali
Keyword(s):  
High Performance ◽  
Noise Figure ◽  
Low Noise ◽  
Low Noise Amplifier ◽  
Long Distance ◽  
High Data ◽  
Receiver System ◽  
Noise Amplifier ◽  
Increasing Demand ◽  
Technology Transformation

<p>Advancement in the wireless industry, internet access without borders and increasing demand for high data rate wireless digital communication moving us toward the optimal development of communication technology. Wireless communication is a technology that plays an important role in current technology transformation. Broadband communication is a method of telecommunication that are available for transmitting large amounts of data, voice and video over long distance using different frequencies. Specifically, Low Noise Amplifier which is located at the first block of receiver system, makes it one of the important element in improving signal transmition. This study was aimed to design a microwave Low Noise Amplifier for wireless application that will work at 5.8 GHz using  high-performance low noise superHEMT transistor FHX76LP manufactured by Eudyna Technologies. The low noise amplifier (LNA) produced gain of 16.8 dB and noise figure (NF) of 1.20 dB. The input reflection (S<sub>11</sub>) and output return loss (S<sub>22</sub>) are -10.5 dB and -13.3 dB respectively. The bandwidth of the amplifier recorded is 1.2 GHz. The input sensitivity is compliant with the IEEE 802.16 standards.</p>

scholarly journals A High-Dynamic-Range Switched-Capacitor Sigma-Delta ADC for Digital Micromechanical Vibration Gyroscopes

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 372 ◽  
Author(s):  
Risheng Lv ◽  
Weiping Chen ◽  
Xiaowei Liu
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Dynamic Range ◽  
Cmos Technology ◽  
Noise Cancellation ◽  
Switched Capacitor ◽  
Noise Shaping ◽  
Sigma Delta ◽  
Multi Stage ◽  
Sigma Delta Adc

This paper presents a multi-stage noise shaping (MASH) switched-capacitor (SC) sigma-delta (ΣΔ) analog-to-digital converter (ADC) composed of an analog modulator with an on-chip noise cancellation logic and a reconfigurable digital decimator for MEMS digital gyroscope applications. A MASH 2-1-1 structure is employed to guarantee an absolutely stable modulation system. Based on the over-sampling and noise-shaping techniques, the core modulator architecture is a cascade of three single-loop stages containing feedback paths for systematic optimization to avoid deterioration in conversion accuracy caused by capacitor mismatch. A digital noise cancellation logic is also included to eliminate residual quantization errors in the former two stages, and those in the last stage are shaped by a fourth-order modulation. A multi-rate decimator follows the analog modulator to suit variable gyroscope bandwidth. Manufactured in a standard 0.35 μm CMOS technology, the whole chip occupies an area of 3.8 mm2. Experimental results show a maximum signal-to-noise ratio (SNR) of 100.2 dB and an overall dynamic range (DR) of 107.6 dB, with a power consumption of 3.2 mW from a 5 V supply. This corresponds to a state-of-the-art figure-of-merit (FoM) of 165.6 dB.

scholarly journals In situtwo-dimensional imaging quick-scanning XAFS with pixel array detector

2011 ◽  
Vol 18 (6) ◽  
pp. 919-922 ◽  
Author(s):  
Hajime Tanida ◽  
Hisao Yamashige ◽  
Yuki Orikasa ◽  
Masatsugu Oishi ◽  
Yu Takanashi ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Low Noise ◽  
Array Detector ◽  
Large Area ◽  
Scanning Method ◽  
Two Dimensional Image ◽  
Pixel Array ◽  
Pixel Array Detector ◽  
Good Signal

Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2 mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10 s to 1 min per spectrum depending on the energy range. The PAD has a wide dynamic range and low noise, so the obtained spectra have a good signal-to-noise ratio.

scholarly journals Design of Microwave LNA Based on Ladder Matching Networks for WiMAX Applications

2016 ◽  
Vol 6 (4) ◽  
pp. 1717
Author(s):  
Abu Bakar Ibrahim ◽  
Ahmad Zamzuri Mohamad Ali
Keyword(s):  
High Performance ◽  
Noise Figure ◽  
Low Noise ◽  
Low Noise Amplifier ◽  
Long Distance ◽  
High Data ◽  
Receiver System ◽  
Noise Amplifier ◽  
Increasing Demand ◽  
Technology Transformation

<p>Advancement in the wireless industry, internet access without borders and increasing demand for high data rate wireless digital communication moving us toward the optimal development of communication technology. Wireless communication is a technology that plays an important role in current technology transformation. Broadband communication is a method of telecommunication that are available for transmitting large amounts of data, voice and video over long distance using different frequencies. Specifically, Low Noise Amplifier which is located at the first block of receiver system, makes it one of the important element in improving signal transmition. This study was aimed to design a microwave Low Noise Amplifier for wireless application that will work at 5.8 GHz using  high-performance low noise superHEMT transistor FHX76LP manufactured by Eudyna Technologies. The low noise amplifier (LNA) produced gain of 16.8 dB and noise figure (NF) of 1.20 dB. The input reflection (S<sub>11</sub>) and output return loss (S<sub>22</sub>) are -10.5 dB and -13.3 dB respectively. The bandwidth of the amplifier recorded is 1.2 GHz. The input sensitivity is compliant with the IEEE 802.16 standards.</p>

scholarly journals Software-defined radio-based HF doppler receiving system

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Hiroyuki Nakata ◽  
Kenro Nozaki ◽  
Yuhei Oki ◽  
Keisuke Hosokawa ◽  
Kumiko K. Hashimoto ◽  
...  
Keyword(s):  
Analog Circuits ◽  
Software Defined Radio ◽  
Analog Circuit ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Digital Signal ◽  
Radio System ◽  
Observation Network ◽  
Receiver System ◽  
New System

AbstractHigh-frequency Doppler (HFD) sounding is one of the major remote sensing techniques used for monitoring the ionosphere. Conventional systems for HFDs mainly utilize analog circuits. However, existing analog systems have become difficult to maintain as the number of people capable of working with analog circuits has declined. To solve this problem, we developed an alternate HFD receiver system based on digital signal processing. The software-defined radio (SDR) technique enables the receiver to be set up without the knowledge of analog circuit devices. This approach also downsizes the system and reduces costs. A highly stabilized radio system for both the transmitter and receiver is necessary for stable long-term observations of various phenomena in the ionosphere. The global positioning system disciplined oscillator with an accuracy of $${10}^{-11}$$ 10 - 11 compensates for the frequency stability required by the new receiving system. In the new system, four frequencies are received and signal-processed simultaneously. The dynamic range of the new system is wider (> 130 dB) than that of the conventional system used in HFD observations conducted by the University of Electro-Communications in Japan. The signal-to-noise ratio significantly improved by 20 dB. The new digital system enables radio waves to be received with much smaller amplitudes at four different frequencies. The new digital receivers have been installed at some of the stations in the HFD observation network in Japan and have already captured various ionospheric phenomena, including medium-scale traveling ionospheric disturbances and sudden commencement induced electric field fluctuations, which indicates the feasibility of SDR for actual ionospheric observations. The new digital receiver is simple, inexpensive, and small in size, which makes it easy to deploy new receiving stations in Japan and elsewhere. These advantages of the new system will help drive the construction of a wide HFD observation network. Graphical Abstract

scholarly journals Extending OTDR Distance Span by External Front-End Optical Preamplifier

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2275
Author(s):  
Adriana Lipovac ◽  
Vlatko Lipovac ◽  
Mirza Hamza ◽  
Vedran Batoš
Keyword(s):  
Dynamic Range ◽  
Noise Figure ◽  
Cost Effective ◽  
Optical Amplifier ◽  
High Gain ◽  
Low Noise ◽  
Long Distance ◽  
Optical Time Domain Reflectometer ◽  
Front End ◽  
Extension Model

Optical time-domain reflectometer (OTDR) is used to characterize fiber optic links by identifying and localizing various refractive and reflective events such as breaks, splices, and connectors, and measuring insertion/return loss and fiber length. Essentially, OTDR inserts a pulsed signal into the fiber, from which a small portion that is commonly referred to as Rayleigh backscatter, is continuously reflected back with appropriate delays of the reflections expressed as the power loss versus distance, by conveniently scaling the time axis. Specifically, for long-distance events visibility and measurement accuracy, the crucial OTDR attribute is dynamic range, which determines how far downstream the fiber can the strongest transmitted optical pulse reach. As many older-generation but still operable OTDR units have insufficient dynamic range to test the far-end of longer fibers, we propose a simple and cost-effective solution to reactivate such an OTDR by inserting a low-noise high-gain optical preamplifier in front of it to lower the noise figure and thereby the noise floor. Accordingly, we developed an appropriate dynamic range and distance span extension model which provided the exemplar prediction values of 30 dB and 75 km, respectively, for the fiber under test at 1550 nm. These values were found to closely match the dynamic range and distance span extensions obtained for the same values of the relevant parameters of interest by the preliminary practical OTDR measurements conducted with the front-end EDFA optical amplifier, relative to the measurements with the OTDR alone. This preliminary verifies that the proposed concept enables a significantly longer distance span than the OTDR alone. We believe that the preliminary results reported here could serve as a hint and a framework for a more comprehensive test strategy in terms of both test diversification and repeating rate, which can be implemented in a network operator environment or professional lab.

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