Crosstalk Problem Research Articles

Digital Predistortion Based on Combined Feedback in MIMO Transmitters

An adaptive digital predistortion (PD) technique is proposed for linearization of power amplifiers (PAs) in multiple-input multiple-output (MIMO) transmitters. Instead of constructing a separate feedback path at each PA, we propose a PD technique based on a combined feedback, which adds all the PAs' outputs to form a single feedback. We develop an algorithm for finding the multiple PA characteristics jointly from the combined feedback. The PD parameters are calculated from the identified PA characteristics. Although the proposed method requires more computations for PA identification than the conventional method, its hardware implementation is much simpler and can overcome the crosstalk problem of a radio frequency (RF) selector, which is necessary for multiple feedback selection. The simulation results show that, despite its simple structure, the linearization performance of the proposed method is almost the same as the separate multiple feedback method.

Simultaneous Reconstruction of Activity and Attenuation in Time-of-Flight PET

In positron emission tomography (PET) and single photon emission tomography (SPECT), attenuation correction is necessary for quantitative reconstruction of the tracer distribution. Previously, several attempts have been made to estimate the attenuation coefficients from emission data only. These attempts had limited success, because the problem does not have a unique solution, and severe and persistent "cross-talk" between the estimated activity and attenuation distributions was observed. In this paper, we show that the availability of time-of-flight (TOF) information eliminates the cross-talk problem by destroying symmetries in the associated Fisher information matrix. We propose a maximum-a-posteriori reconstruction algorithm for jointly estimating the attenuation and activity distributions from TOF PET data. The performance of the algorithm is studied with 2-D simulations, and further illustrated with phantom experiments and with a patient scan. The estimated attenuation image is robust to noise, and does not suffer from the cross-talk that was observed in non-TOF PET. However, some constraining is still mandatory, because the TOF data determine the attenuation sinogram only up to a constant offset.

Combined Acoustic MIMO Channel Crosstalk Cancellation and Room Impulse Response Reshaping

Virtual 3-D sound can be easily delivered to a listener by binaural audio signals that are reproduced via headphones, which guarantees that only the correct signals reach the corresponding ears. Reproducing the binaural audio signal by two or more loudspeakers introduces the problems of crosstalk on the one hand, and, of reverberation on the other hand. In crosstalk cancellation, the audio signals are fed through a network of prefilters prior to loudspeaker reproduction to ensure that only the designated signal reaches the corresponding ear of the listener. Since room impulse responses are very sensitive to spatial mismatch, and since listeners might slightly move while listening, robust designs are needed. In this paper, we present a method that jointly handles the three problems of crosstalk, reverberation reduction, and spatial robustness with respect to varying listening positions for one or more binaural source signals and multiple listeners. The proposed method is based on a multichannel room impulse response reshaping approach by optimizing a -norm based criterion. Replacing the well-known least-squares technique by a -norm based method employing a large value for allows us to explicitly control the amount of crosstalk and to shape the remaining reverberation effects according to a desired decay.

Crosstalk Analysis for Microring Based Optical Interconnection Networks

Recently a new approach was proposed to tackle the wavelength non-uniformity problem of the silicon photonic ring technology. By lowering the Q value of the ring, the likelihood of finding a common operating wavelength can be significantly increased. But lowering Q will increase the crosstalk level in such a network. This crosstalk problem can be tackled with a generalized space dilation technique. Since crosstalk is a central issue of this approach, computing the crosstalk level accurately is critical for a microring-based photonic interconnect. Prior work on crosstalk analysis for interconnects based on directional couplers assumed that the extinction ratios are the same for the two switching states. But this is usually not the case for silicon photonic microrings. In this paper, we develop an analytical model for analyzing the crosstalk level in a microring-based optical interconnection network. The analytical approach presented in the paper can be used for studying the crosstalk problem in optical networks based on other optical switching technologies.

ChemInform Abstract: Viewing Spin Structures with Soft X‐Ray Microscopy

AbstractReview: 102 refs.

A serious problem in using the Jarvis model for the prediction of crosstalk

The coupled transmission-line equations for a three-conductor, lossless transmission line are solved in symbolic form for its crosstalk voltages using various approximations [1, 2]. The most frequently-used approximate model for predicting crosstalk is referred to as the Jarvis model after its original publisher in 1963 [3]. The Jarvis model uses three approximations that simplify the result. One of the approximations requires that all four line terminations be matched which is unrealistic for virtually all crosstalk problems.

Full-field chromatic confocal surface profilometry employing digital micromirror device correspondence for minimizing lateral cross talks

Full-field chromatic confocal surface profilometry employing a digital micromirror device (DMD) for spatial correspondence is proposed to minimize lateral cross-talks between individual detection sensors. Although full-field chromatic confocal profilometry is capable of enhancing measurement efficiency by completely removing time-consuming vertical scanning operation, its vertical measurement resolution and accuracy are still severely affected by the potential sensor lateral cross-talk problem. To overcome this critical bottleneck, a DMD-based chromatic confocal method is developed by employing a specially-designed objective for chromatic light dispersion, and a DMD for lateral pixel correspondence and scanning, thereby reducing the lateral cross-talk influence. Using the chromatic objective, the incident light is dispersed according to a pre-designed detection range of several hundred micrometers, and a full-field reflected light is captured by a three-chip color camera for multi color detection. Using this method, the full width half maximum of the depth response curve can be significantly sharpened, thus improving the vertical measurement resolution and repeatability of the depth detection. From our preliminary experimental evaluation, it is verified that the ±3σ repeatability of the height measurement can be kept within 2% of the overall measurement range.

Evaluation and optimization of multiple fluorophore analysis of a Pseudomonas aeruginosa biofilm

Conventional laser scanning microscopy for multiple fluorescent stains can be a useful tool if the problems of autofluorescence and cross-talk are eliminated. The technique of spectral imaging was employed to unmix five different fluorophores – ranging in emission from 435 to 665nm – applied to a Pseudomonas aeruginosa biofilm with overlapping spectra and which was not possible using traditional channel mode operation. Using lambda scanning and linear unmixing, the five fluorophores could be distinguished with regions of differentiation apparent.

Response analysis of holography-based modal wavefront sensor

The crosstalk problem of holography-based modal wavefront sensing (HMWS) becomes more severe with increasing aberration. In this paper, crosstalk effects on the sensor response are analyzed statistically for typical aberrations due to atmospheric turbulence. For specific turbulence strength, we optimized the sensor by adjusting the detector radius and the encoded phase bias for each Zernike mode. Calibrated response curves of low-order Zernike modes were further utilized to improve the sensor accuracy. The simulation results validated our strategy. The number of iterations for obtaining a residual RMS wavefront error of 0.1λ is reduced from 18 to 3.

Crosstalk analysis of carbon nanotube bundle interconnects

Carbon nanotube (CNT) has been considered as an ideal interconnect material for replacing copper for future nanoscale IC technology due to its outstanding current carrying capability, thermal conductivity, and mechanical robustness. In this paper, crosstalk problems for single-walled carbon nanotube (SWCNT) bundle interconnects are investigated; the interconnect parameters for SWCNT bundle are calculated first, and then the equivalent circuit has been developed to perform the crosstalk analysis. Based on the simulation results using SPICE simulator, the voltage of the crosstalk-induced glitch can be reduced by decreasing the line length, increasing the spacing between adjacent lines, or increasing the diameter of SWCNT.

GENERALIZED EQUIVALENT CABLE BUNDLE METHOD FOR MODELING EMC ISSUES OF COMPLEX CABLE BUNDLE TERMINATED IN ARBITRARY LOADS

A generalized equivalent cable bundle method (GECBM) is presented for modeling electromagnetic (EM) compatibility issues of complex cable bundle terminated in arbitrary loads. By introducing a new grouping criterion, complex cable bundles terminated in arbitrary loads can be reasonably simplifled through a generalized equivalence procedure. The reduced cable bundle model can be used for modeling electromagnetic immunity, emission and crosstalk problems. The complexity and the computation time for the complete cable bundle modeling has been signiflcantly reduced and fairly good precision is maintained. Numerical simulations are given to validate the e-ciency and advantages of the method.

Design and cold test of S-BAND cavity BPM for HLS

An S-band cavity BPM is designed for a new injector in National Synchrotron Radiation Laboratory. A re-entrant position cavity is tuned to the TM110 mode as position cavity. Cut-through waveguides are used as pickups to suppress the monopole signal. Theoretical resolution of this design is 31 nm. A prototype cavity BPM system is manufactured for off-line cold tests. The wire scanning method is used to calibrate the BPM and estimate the performance of the on-line BPM system. A cross-talk problem has been detected during the cold test. Racetrack cavity BPM design can be used to suppress the cross-talk. With the nonlinear effect being ignored, transform matrix can be used to correct cross-talk. Analysis of cold test results shows that the position resolution of prototype BPM is better than 3 m. cavity BPM, re-entrant, cut-through waveguide, cold test, wire scanning, resolution, cross-talk

Carbon Nanotubes Bundled Interconnects: Design Hints Based on Frequency- and Time-Domain Crosstalk Analyses

In this paper, the crosstalk problem for carbon nanotubes (CNTs) bundled interconnects is modeled in the framework of the multiconductor transmission line (MTL) theory by using a fluid description of the conduction phenomena in CNTs. Two two-port models for a two-line interconnect (one aggressor and one victim) are proposed. The first is based on the full-MTL equations coupling each CNT in the bundles. The second, which is a reduced order TL model coupling the CNT bundles, is derived from the first one and used for fast computations. The crosstalk models are used to study the impact on relevant electromagnetic performances of some actual technological and design aspects, such as the variability of the number of conducting CNTs in each bundle, their position in the cross section, the proximity of the signaling lines, the cross-sectional aspect ratio, and some advances in CNT manufacturing techniques. Both frequency- and time-domain characteristics are evaluated and compared with those of ideally scaled traditional copper interconnects. The results are compared with those obtained by simplified approaches, showing, in particular, that simple RC models may underestimate the crosstalk.

Electronic Nose using Gas Chromatography Column and Quartz Crystal Microbalance

The conventional electronic nose usually consists of an array of dissimilar chemical sensors such as quartz crystal microbalance (QCM) combined with pattern recognition algorithm such as Neural network. Because of parallel processing, the system needs a huge number of sensors and circuits which may emerge complexity and inter-channel crosstalk problems. In this research, a new type of odor identification which combines between gas chromatography (GC) and electronic nose methods has been developed. The system consists of a GC column and a 10-MHz quartz crystal microbalance sensor producing a unique pattern for an odor in time domain. This method offers advantages of substantially reduced size, interferences and power consumption in comparison to existing odor identification system. Several odors of organic compounds were introduced to evaluate the selectivity of the system. Principle component analysis method was used to visualize the classification of each odor in two-dimensional space. This system could resolve common organic solvents, including molecules of different classes (aromatic from alcohols) as well as those within a particular class (methanol from ethanol) and also fuels (premium from pertamax). The neural network can be taught to recognize the odors tested in the experiment with identification rate of 85 %. It is therefore the system may take the place of human nose, especially for poisonous odor evaluations.

Cross-talk prevention in optical dynamic measurement

In interferometry-based optical dynamic measurement, single high-speed camera or photodetector is normally adopted to avoid critical alignment and synchronization problems. Due to the rapid development of high-speed cameras and photodetectors, the signal obtained is sufficient to encode different dynamic informations. However, cross-talk problem always exists. In order to avoid the influence of cross-talk, well-designed carriers must be adopted in either spatial or temporal domain. In this paper, we will present two applications on cross-talk prevention in optical dynamic measurement. The first one is a camera-based dual-wavelength image-plane digital holography. In this application, the direction of two spatial carriers is designed to encode information of two wavelengths at different areas of the spectrum. Two phase maps can be retrieved from one hologram. The second application is a spatially encoded multi-beam laser Doppler vibrometry using a single detector. It encodes vibration information of 20 points on separated frequency ranges. Three methods that can bypass the cross-talk are discussed. The experiment verifies it is possible to do a precise vibration measurement on a 4×5 matrix simultaneously using a single photodetector.

Peripheral Ferroelectric Domain Switching and Polarization Fatigue in Nonvolatile Memory Elements of Continuous Pt/SrBi2Ta2O9/Pt Thin-Film Capacitors

We verify the domain sideway motion around the peripheral regions of the crossed capacitors of top and bottom electrode bars without electrode coverage. To avoid the crosstalk problem between adjacent memory cells, the safe distance between adjacent elements of Pt/SrBi2Ta2O9/Pt thin-film capacitors is estimated to be 0.156 μm. Moreover, the fatigue of Pt/SrBi2Ta2O9/Pt thin-film capacitors is independent of the individual memory size due to the absence of etching damage.

Tests of the MICE Electron Muon Ranger frontend electronics with a small scale prototype

The MICE experiment is being commissioned at RAL to demonstrate the feasibility of the muon ionization cooling technique for future applications such as the Neutrino Factory and the Muon Collider. The cooling will be evaluated by measuring the emittance before and after the cooling channel with two 4 T spectrometers; to distinguish muons from the background, a multi-detector particle identification system is foreseen: three Time of Flight stations, two Cherenkov counters and a calorimetric system consisting of a pre-shower layer and a fully active scintillator detector (EMR) are used to discriminate muons from pions and electrons. EMR consists of 48 planes of triangular scintillating bars coupled to WLS fibers readout by single PMTs on one side and MAPMTs on the other; each plane sensible area is 1 m 2. This article deals with a small scale prototype of the EMR detector which has been used to test the MAPMT frontend electronics based on the MAROC ASIC; the tests with cosmic rays using both an analog mode and a digital readout mode are presented. A very preliminary study on the cross talk problem is also shown.

Nanoscale Two-Bit/Cell NAND Silicon-Oxide-Nitride-Oxide-Silicon Devices with a Separated Double-Gate Saddle-Type Structure

Nanoscale two-bit/cell NAND silicon-oxide-nitride-oxide-silicon flash memory devices based on a separated double-gate (SDG) saddle structure with a recess channel region had two different doping regions in silicon-fin channel to operate two-bit per cell. A simulation results showed that the short channel effect, the cross-talk problem between cells, and the increase in threshold voltage distribution were minimized, resulting in the enhancement of the scaling-down characteristics and the program/erase speed.

Virtual Ground Technique for Crosstalk Suppression in Networked Resistive Sensors

Two-dimensional resistive sensor arrays that utilize shared row and column connections to simplify the interconnect complexity suffer from the crosstalk problem among its elements introduced due to the interconnection overloading. In this letter, we present a method of overcoming the problem of crosstalk by putting all of the row nodes at virtually equal potential using virtual ground of high-gain operational amplifiers (opamps) in negative feedback. The circuit, though it requires a large number of opamps, solves the crosstalk problem to a large extent and provides faster scanning. We verified the circuit functionality with PSPICE simulations. We have also derived the expressions of crosstalk rejection and sensitivity to show that, by using high-gain, low-noise opamps, we may get excellent performance.

Reliable Procedures to Evaluate and Repair Crosstalk for Bioanalytical MS/MS Assays

Louis-Philippe Morin is a senior instrument application specialist at Algorithme Pharma, a CRO located in Laval, Canada. He has been working in the bioanalysis industry for the past 10 years where he became a subject matter expert in analytical instrumentation, especially in the MS field. His responsibilities in his current position are to optimize the workflow of the laboratory and to find new procedures, or approaches, to fix complex analytical problems. Louis-Philippe's expertise acquired over the years has led him to multiple publications regarding instrumentation. LC-MS/MS is the analytical technique of choice for the quantification of drugs in biological fluids. In recent years, MS/MS detection has been impacted by the rapid evolution of bioanalysis industry requirements. The availability of fast chromatographic systems, the demand for wider dynamic ranges and the extensive use of stable isotope-labeled internal standards in bioanalysis has pushed some triple quadrupole detectors to their limits of operation. Consequently, this situation has led to a re-evaluation of the problem of crosstalk as a potential cause of issues in bioanalysis. In this article, the importance of crosstalk verification on the MS/MS instrument will be demonstrated. Additionally, procedures to identify, evaluate and fix possible crosstalk issues during bioanalytical assays on MS/MS instruments are proposed.