Cable Links Research Articles

Time transfer via single‐record TDoA measurements of GNSS satellites using direct cross‐correlation and relative pilot code phases

AbstractRadar systems are evolving towards distributed receiver networks. As individual stations might be separated too far to install a cable link, novel methods are required to synchronise individual data records in the time domain. State‐of‐the‐art GNSS receivers disciplining a highly stable oscillator are able to output a timing signal with several nanosecond accuracy solely using non‐proprietary signals. However, they typically require a stable environment and become a major cost factor for receiver networks with a high number of nodes. A method is presented to passively synchronise data records via GNSS raw signals in a single record requiring only a GNSS antenna, an analogue‐to‐digital converter and computation hardware. The clock bias is estimated via the common view method with either full raw signal correlation or software‐based code correlation of individual signals from the GPS, Galileo and BeiDou constellation with sub‐nanosecond precision.

Protecting submarine cables for enhanced connectivity

Protecting submarine cables for enhanced connectivity Morten Eriksrud, at ASN Norway AS, looks to the protection of the global network of submarine cables and other critical subsea infrastructure. Optical communication technology is the key technology to making internet connectivity available all over the world. Fibre-optic cables, distributing data with the speed of light, connect continents, countries, and islands together by creating a global telecommunication network. These cables are installed subsea and are placed on the seafloor (in deep water areas) or trenched in the seabed (in shallow water areas). This global network of submarine cables contains more than 400 active cable links covering nearly 1.4 million kilometres (over three times the distance from Earth to Moon). More than 95% of the global internet traffic runs through these submarine cables. Submarine cables can carry far more data at far less cost than satellites and the increasing digitalization of our societies will further increase the number of submarine cables.

Dynamic model of a tendon-actuated snake robot using the Newton-Euler formulation

Dynamic models are necessary when dealing with robotic applications where requirements of dexterity, manipulability, payload and compliance have to be satisfied at the same time. This work considers a particular design of tendon-actuated snake-like robots in which links are not coupled through mechanical joints but are free to roll between each other under the effect of cable tension forces. The state of the art in modeling these tendon-actuated rolling-joints systems is limited to kinematic and quasi-static models. In order to simultaneously guarantee modeling accuracy and suitability for model-based control, the Newton-Euler (NE) formulation has been adopted, by taking into account the forces and moments generated by cable tensions, links interactions, inertias, and friction between the rolling surfaces.

The ultrafast pixel array camera system and its applications in high energy density physics.

Diagnostics in high energy density physics, shock physics, and related fields are primarily driven by a need to record rapidly time-evolving signals in single-shot events. These measurements are often limited by channel count and signal degradation issues on cable links between the detector and digitizer. We present the Ultrafast Pixel Array Camera (UPAC), a compact and flexible detector readout system with 32 waveform-recording channels at up to 10 Gsample/s and 1.8GHz analog bandwidth. The compact footprint allows the UPAC to be directly embedded in the detector environment. A key enabling technology is the PSEC4A chip, an eight-channel switch-capacitor array sampling device with up to 1056 samples/channel. The UPAC system includes a high-density input connector that can plug directly into an application-specific detector board, programmable control, and serial readout, with less than 5W of power consumption in full operation. We present the UPAC design and characterization, including a measured timing resolution of ∼20ps or better on acquisitions of sub-nanosecond pulses with minimal system calibrations. Example applications of the UPAC are also shown to demonstrate operation of a solid-state streak camera, an ultrafast imaging array, and a neutron time-of-flight spectrometer.

Passive Impedance Sensing Using a SAW Resonator-Coupled Biosensor for Zero-Power Wearable Applications

A bio-sensing scheme, which acquires impedance information of a capacitive biosensor by using the reflected RF signal from a surface acoustic wave (SAW) resonator connected to the biosensor, is proposed. This technique requires no power to be supplied to the biosensor node and hence is highly applicable to wearable applications. Theoretical analysis has demonstrated that the sensitivity of the SAW resonator-coupled biosensor is higher than that of traditional impedance loaded SAW sensors and therefore it is more suitable for measuring the very small impedance changes in biosensors. The passive detection of the change in the impedance of a capacitive biosensor, as a result of biological binding events associated with the capture of a target analyte, has been demonstrated by preliminary experimentation. Dry tests of the SAW coupled capacitive biosensor using a cable connected network analyzer showed the aF level capacitance measurement resolution, which was only achieved in transistor level circuits previously, could be attained. When liquid samples with concentrations of C-Reactive Protein (CRP) in the range of 0.1 to 2 μg/ml were applied to the biosensor, a corresponding change in the resonant frequency of the SAW resonator-coupled biosensor (in the order of sub-hundred kHz) was observed. This has demonstrated the potential for applying this technique in applications where a zero-power requirement at the biosensor node could be a distinct advantage, when the cable link between the network analyzer and the biosensor node is replaced by the RF transmission.

Design of GEMSTAR tidal current fixed pitch rotor controlled through a Permanent Magnet Generator (PMG) de‐fluxing technique

This work reports a study on a tidal current system named GEMSTAR, composed of two hydrokinetic turbines supported by a floating submerged structure. A flexible mooring cable links the floating support to the seabed allowing the free rotation of the system and its alignment to changing current direction. The work is mainly focused on the design of the turbine blade with two objectives: keeping a constant power output above the rated power condition and limiting the thrust increase between rated and maximum operating speed. A fixed pitch blade was considered, in order to reduce the costs associated to a complex pitch control mechanism. An analytical procedure for blade design is proposed and validated by comparison to other numerical methods. Above the rated current speed, the power is held constant while the rotational speed of the turbine and of the generator increases, assuming an over-speeding control strategy. The adopted design configuration relies on the possibility of the generator to operate in de-fluxing working conditions. As reported in the last part of this study, a numerical model of the generator has also been developed and applied to a test case in order to analyse the electric behaviour of the system.

Modeling and Assessment of Short-Term Electromagnetic Interference on a Railway System From Pole-to-Ground Faults on VSC-HVDC Cable Networks With Sea Electrodes

This work falls under the preliminary engineering studies that are carried out to assess the interference impact, which may be raised from the operation of the bipolar HVdc cable link between Attica and Crete. The interference impact concerns critical and public infrastructures that are located in close proximity to the intended link's on-shore routing. In this article, particular emphasis is given in modeling a specific interference situation, on a collocated railway system, that ascends from pole-to-ground fault conditions that may occur on the planned bipolar voltage source converter (VSC)-HVdc cable network. To this extent, the simulation analysis takes into account the specific characteristics of the interfering VSC-HVdc technology and the results are constructively benchmarked against the safety thresholds tabulated in international standards.

Kinematic Modeling and Analysis of a Novel Bio-Inspired and Cable-Driven Hybrid Shoulder Mechanism

Abstract The robotic shoulder rehabilitation exoskeletons that do not take into consideration all shoulder degrees-of-freedom (DOFs) lead to undesirable interaction forces and cause discomfort to the patient due to the joint axes misalignments between the exoskeleton and shoulder joints. In order to contribute to the solution of this human–robot compatibility issue, we present the kinematic modeling and analysis of a novel bio-inspired 5-DOFs hybrid human–robot mechanism (HRM). The human limbs are regarded as the inner passive restrained links in the proposed hybrid constrained anthropomorphic mechanism. The proposed hybrid mechanism combines serial and parallel manipulators with rigid and cable links enabling a match between human and exoskeleton joint axes. It is designed to cover the whole range of motion of the human shoulder with the workspace free of singularities. The numerical and simulation results from the computer-aided drawing model of the mechanism are presented to demonstrate the validity of the kinematic model, and the kinematic and singularity merits of the proposed mechanism. A three-dimensional printed prototype of the hybrid mechanism was fabricated to further validate the kinematic model and its overall advantages.

Investigation on design methods for cable mesh configuration of deployable space antenna reflector

Mesh reflectors are always a preferable option for large size deployable antenna reflector over solid surface reflectors due to their flexibility of adjustment in minimum possible space and ability to get deployed to full configuration in space. Maintaining surface properties and accuracy are two important requirements in the design of the mesh reflector for the performance of cable network antenna reflectors. The present work considers the various design approaches for cable mesh configuration of space deployable antenna reflectors. The equal force density shape forming criteria such is applied for obtaining the desired parabolic curvature of the mesh configuration. The ring structure for the deployable mechanism is considered as rigid linkages for designing mesh configuration. A generalized numbering scheme for nodes and cable mesh link is formulated for carrying forward various shapes forming criteria which help in making an algorithm. The algorithm for a better understanding of these methods is developed using MATLAB with nodal coordinates and its connection. Mesh configuration is developed with a different number of divisions. A study is also carried out for finding the required number of divisions for a highly accurate parabolic profile for a particular band frequency. A demonstration model is developed and a comparison of the coordinates of the prototype is made with those arrived at using the model.

Wireless Powering of Next-Generation Left Ventricular Assist Devices (LVADs) Without Percutaneous Cable Driveline

This article deals with the design of a wireless powering system for a left ventricular assist device (LVAD). The modern LVAD is mainly a miniaturized blood pump attached to the heart and is driven by an electric motor powered by a cable driveline that exits the patient's body through the skin to be connected with an external battery. The driveline is a portal to the exterior environment and this can cause frequent and severe infections. The goal of this article is the elimination of the cable link between the interior and the exterior of the human body. To this aim, an innovative powering design of the LVAD is proposed adopting the wireless power transfer (WPT) technology based on magnetic resonant coupling. The main challenges in the design of a WPT system for LVAD application are the considerable implantation depth (5-10 cm) and the relatively high power (≈5 W) required by the device to operate continuously. Two different design solutions are proposed: 1) a subcutaneous receiving coil connected to the LVAD by a short driveline completely inside the human body and 2) an LVAD with a receiving circuit and coil, both integrated on it.

On control and balancing of rigid bipolar MMC-HVdc links enabling subsystem-independent power transfer

High voltage direct current transmission schemes equipped with modular multilevel converter technology are considered in several realized and planned bulk power transmission projects. Especially in the case of dc cable links with high system lengths, the rigid bipolar configuration presents a suitable compromise between power rating, cost-efficiency and converter redundancy. Caused by the absence of a metallic return path, system degrees of freedom are reduced in contrast to the bipolar configuration with dedicated metallic return. Therefore, the dc currents in positive and negative bipolar subsystem are not independent. This leads to new challenges and motivates the development of advanced control and balancing concepts for rigid bipolar schemes. This paper focuses on balanced and unbalanced ac grid operating conditions with subsystem-independent active power set points in an ac split-busbar scenario, which has not yet been covered in literature. In order to validate the presented methodology, case studies are performed in electromagnetic transient software.

Time domain dielectric response of field grading sleeves subjected to high humidity and temperatures

It is experienced that MV XLPE cable links including heat shrink cable joints can have a high electrical conductivity compared to the XLPE cable insulation. The field grading sleeve included in the joint design is proposed to be responsible for the reduced insulation resistance and is therefore studied in this paper. New field grading sleeves are aged in the laboratory at temperatures up to 150 °C in both dry and humid conditions. The degree of ageing is determined by DSC measurements, the mechanical properties are determined by tensile strength testing, and the electric properties are characterized by time domain dielectric response measurements. The results show that after only a few days above the melting point of 104 °C the tensile strength of the material is strongly reduced. The electrical conductivity is strongly dependent on the degree of thermal ageing of the sleeve material but also the water content. The combination of significant thermal degradation and a high water content results in particularly high conductivity values. It is shown that the increase of the conductivity after ageing at 150 °C for 15 days is five orders of magnitude for wetted field grading sleeves measured at 30 °C.

PD08-04 BIO-ENGINEERING OF A NOVEL BLUETOOTH TELEMETRICALLY CONTROLLED ARTIFICIAL URINARY SPHINCTER

INTRODUCTION AND OBJECTIVES:The artificial urinary sphincter (AUS) for post-prostatectomy stress urinary incontinence (PPI) has become the gold standard treatment. Precision Medical Devices (PMD) has developed a new AUS. The Politano-Sayet-Sutherland Flow Control Device (PSS-FCD) has undergone 6 previous prototypes before establishing this current model. The current working model is composed of 3 elements: 1) Control/Battery Pack (CBP) 2) Valve assembly with separate Anvil Cap piece; 3) Remote Master Control Module (MCM).METHODS:The CBP consists of electronic and drive components. A printed circuit board, stepper motor and a lithium cell array are contained in the fully, hermetically-sealed waterproof titanium casing.The valve assembly consists of a cable link, a plunger and two shell halves. The cable link connects the cuff and plunger to the CBP. The CBP opens and closes the plunger via the drive assembly and has the ability to adjust the magnitude of closure force with 10 different settings based on co...

Cable links designing in HVAC and HVDC submarine power grids - selected issues

Cable links designing in HVAC and HVDC submarine power grids - selected issues

Phase Drift Compensating RF Link for Femtosecond Synchronization of E-XFEL

Modern high-energy particle accelerators and free-electron lasers incorporate large quantities of sensitive RF and microwave devices distributed over several kilometers. Such devices require extremely stable phase and time synchronization by means of high-frequency signals distributed along the accelerator facility. Coaxial cables are frequently used to distribute the reference signal over the large machine to synchronize electronic systems. These cables are the main source of undesirable phase drifts in the synchronization system. Signal phase drifts in cables are mainly caused by temperature and humidity variations and their values usually exceed required phase synchronization accuracy by more than an order of magnitude. Air pressure can also influence on the signal phase drifts but with a much smaller impact than from temperature and humidity changes. There are several approaches to reduce signal phase drifts in coaxial cables. This article describes the realization of an active phase stabilization system based on the interference phenomenon. A phase-locked signal from the transmitter is reflected at the end of a coaxial cable link. Directional couplers placed along the cable pick up the forward and reflected signals and interfere them to cancel out the cable phase drifts. Distributed hardware, including interferometer controller/transmitter and receiver modules, was built to demonstrate the system concept and performance. FPGA I/O boards with an Ethernet interface are used to control the system operation. Specialized firmware and software were developed to calibrate and control the system. This article describes the concept of the interferometer link, the designed hardware, basic control algorithms, and performance evaluation results. A prototype of the link was built to distribute a 1.3-GHz signal through a coaxial cable. Measured values of the phase drift suppression factor exceeded the level of 100.

Experimental Validation of Three-Dimension Multiconductor Cell Analysis by a 30 km Submarine Three-Core Armoured Cable

In this paper, an experimental validation of three-dimension multiconductor cell analysis (MCA) is presented: a measurement campaign has been performed on Capri–Torre Annunziata three-core 29.5 km long submarine cable link. All the theoretical conclusions derived by the authors in a previous paper are now experimentally confirmed and the model is, therefore, validated. Based on the example in this paper, the maximum difference between MCA results and measurements is 7% on the positive sequence resistance at power frequency. A 10% difference occurs in the evaluation of positive sequence reactance. The agreement between MCA and real measurements in zero sequence impedance is very good with differences lower than 5% in real and imaginary parts.

A Novel Fault Location Method for a Cross-Bonded HV Cable System Based on Sheath Current Monitoring.

In order to improve the practice in the operation and maintenance of high voltage (HV) cables, this paper proposes a fault location method based on the monitoring of cable sheath currents for use in cross-bonded HV cable systems. This method first analyzes the power–frequency component of the sheath current, which can be acquired at cable terminals and cable link boxes, using a Fast Fourier Transform (FFT). The cable segment where a fault occurs can be localized by the phase difference between the sheath currents at the two ends of the cable segment, because current would flow in the opposite direction towards the two ends of the cable segment with fault. Conversely, in other healthy cable segments of the same circuit, sheath currents would flow in the same direction. The exact fault position can then be located via electromagnetic time reversal (EMTR) analysis of the fault transients of the sheath current. The sheath currents have been simulated and analyzed by assuming a single-phase short-circuit fault to occur in every cable segment of a selected cross-bonded high voltage cable circuit. The sheath current monitoring system has been implemented in a 110 kV cable circuit in China. Results indicate that the proposed method is feasible and effective in location of HV cable short circuit faults.

Оценка допусков элементов схемы замещения имитатора кабельных линий связи

The present paper concerns a simulator’s scheme of cable links based on the equivalent circuit of RLC-chains on the lumped elements and controlling apparatus based on the programmed microcontroller to test the systems of signals transmission through the wired communication links. The information about the emulated cable’s type, its length and diameter of cable’s lead, presence of noise and its level, is inputted by means of a keyboard to a microcontroller, which, as per the inputted data, carries out commutation of cable net’s links and their elements in order to form the cable lines with necessary parameters. The simulator of cable lines emulates the parameters and characteristics of the symmetric copper communications links of different types, cable’s lead diameter and dimension of communications link. The simulator also sets the necessary relation of the signal/noise on the communications link output. It provides a value of variation of parameters influence degree of the equivalent circuit’s lumped elements on the frequency response changing of the emulated cable line. Taking into account an equivalent circuit’s lumped elements, the paper studies a degree of parameters variation influence upon changing the frequency response of the emulated cable line. As a result, we obtain the analytical and graphical functions of a cable line’s attenuation factor module sensitivity to the equivalent circuit parameters of lumped elements.

Performance Comparison of R-PHY and R-MACPHY Modular Cable Access Network Architectures

Emerging modular cable network architectures distribute some cable headend functions to remote nodes that are located close to the broadcast cable links reaching the cable modems (CMs) in the subscriber homes and businesses. In the remote-PHY (R-PHY) architecture, an R-PHY device conducts the physical layer processing for the analog cable transmissions, while the headend runs the data over cable service interface specification (DOCSIS) medium access control (MAC) for the upstream transmissions of the distributed CMs over the shared cable link. In contrast, in the remote MACPHY (R-MACPHY) architecture, an R-MACPHY device (RMD) conducts both the physical and MAC layer processing. In this paper, we conduct a comprehensive performance comparison of the R-PHY and R-MACPHY architectures. We first develop analytical delay models for the polling-based MAC with gated bandwidth allocation of Poisson traffic in the R-PHY and R-MACPHY architectures. We then conduct extensive simulations to assess the accuracy of the analytical model and to evaluate the delay-throughput performance of the R-PHY and R-MACPHY architectures for a wide range of deployment and operating scenarios. Our evaluations include long converged interconnect network (CIN) distances between remote nodes and headend, bursty self-similar traffic, and double-phase polling to mask long CIN propagation distances. We find that for long CIN distances above 100 miles, the R-MACPHY architecture achieves significantly shorter mean upstream packet delays than the R-PHY architecture, especially for bursty traffic. Our extensive comparative R-PHY and R-MACPHY evaluation can serve as a basis for the planning of modular broadcast cable based access networks.

Cable links and L-space surgeries

An L-space link is a link in S^3 on which all sufficiently large integral surgeries are L-spaces. We prove that for m, n relatively prime, the r -component cable link K_{rm,rn} is an L-space link if and only if K is an L-space knot and n/m \geq 2g(K)-1 . We also compute \mathrm {HFL}^– and \widehat {\mathrm {HFL}} of an L-space cable link in terms of its Alexander polynomial. As an application, we confirm a conjecture of Licata [7] regarding the structure of \widehat {\mathrm {HFL}} for (n,n) torus links.