Crosstalk Cancellation Research Articles

Multizone Speech Reinforcement

In this article, we address speech reinforcement (near-end listening enhancement) for a scenario where there are several playback zones. In such a framework, signals from one zone can leak into other zones (crosstalk), causing intelligibility and/or quality degradation. An optimization framework is built by exploring a signal model where effects of noise, reverberation and zone crosstalk are taken into account simultaneously. Through the symbolic usage of a general smooth distortion measure, necessary optimality conditions are derived in terms of distortion measure gradients and the signal model. Subsequently, as an illustrative example of the framework, the conditions are applied for the mean-square error (MSE) expected distortion under a hybrid stochastic-deterministic model for the corruptions. A crosstalk cancellation algorithm follows, which depends on diffuse reverberation and across zone direct path components. Simulations validate the optimality of the algorithm and show a clear benefit in multizone processing, as opposed to the iterated application of a single-zone algorithm. Also, comparisons with least-squares crosstalk cancellers in literature show the profit of using a hybrid model.

波长变换技术对拉曼串扰的影响

波长变换技术对拉曼串扰的影响

Electrical method for crosstalk cancellation in transducer arrays

In this paper, we report a new and simple electrical method to cancel crosstalk in the acoustical arrays. This solution has several advantages compared with that proposed in a previous paper (Bybi et al 2013) [17] where adapted electrical voltages were applied to each neighboring element of the active element in order to reduce the displacement field on their active surface. Firstly, it allows obtaining accurate correction electrical voltages, since it requires average electrical measurements (impedance and current measurements) instead of the displacement measurement in each point at the surface of the radiated element. In addition to this, the method does not need a laser vibrometer which is expensive in terms of time and difficult to use accurately for displacement measurement in water. To demonstrate the ability of the proposed solution an array composed of seven-elements, similar to those used in medical imaging and NDT applications, made of a conventional piezo-ceramic material PZT-27 is fabricated. Then an electrical method based on electromechanical equivalent circuits for piezoelectric materials and motional current measurements is applied. The experimental and numerical results obtained demonstrate the ability of the proposed technique to reduce crosstalk as well as its robustness and ease of implementation.

Crosstalk Cancellation on High-Speed Interconnects Through a MIMO Linear Precoding

One of the main problems of multiple-input multiple-output (MIMO) high-speed interconnect (HSI) circuits that use single-ended signaling is crosstalk phenomena. Crosstalk is an unintentional coupling of the transmitted signals due to close spacing between transmission lines that distorts the information bearing symbols. A novel model for uniform or nonuniform multiconductor transmission line based on the S-parameters is proposed. It allows representation of an HSI as a MIMO channel. In addition, a linear precoding scheme stands on the aforementioned signal model and wireless digital precoding. The precoder generates eigen-beam patterns designed to avoid crosstalk. This research employs practical HSI circuits used in system-in-package at data rates of 2 Gb/s. Statistical link simulation results are presented to analyze and verify the performance and benefits in terms of signal integrity quality of the signal model and the linear precoder proposed.

A 10-Gb/s Adaptive Parallel Receiver With Joint XTC and DFE Using Power Detection

A 10-Gb/s adaptive parallel receiver with joint crosstalk canceller (XTC) and decision-feedback equalizer (DFE) is presented. A differentiator-based XTC and a one-tap DFE are adapted to cancel far-end crosstalk (FEXT) and inter-symbol interference (ISI), respectively. When the lengths of the coupled microstrip lines change, an FEXT detector measures and compares the powers of FEXT and XTC to digitally update the XTC coefficient. Then, an ISI detector measures and compares the powers of the received data and recovered data to digitally update the DFE coefficient. This adaptive parallel receiver was fabricated in a 40-nm CMOS technology. The maximum power consumption is 17.55 mW from a 1.3-V supply, and the core area occupies 0.0352 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . For a 10-Gb/s PRBS of 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> -1 passing through 15-in FR4 printed-circuit-board traces with 8-mil spacing, the measured rms and peak-to-peak jitter of recovered data are 5.56 and 30.2 ps, respectively. The measured bit error rate is less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> . The measured total calibration time is 2.424 μs.

Distributed Linear Convolutional Space-Time Coding for Two-Relay Full-Duplex Asynchronous Cooperative Networks

In this paper, a two-relay full-duplex asynchronous cooperative network with the amplify-and-forward (AF) protocol is considered. We propose two distributed space-time coding schemes for the cases with and without cross-talks, respectively. In the first case, each relay can receive the signal sent by the other through the cross-talk link. We first study the feasibility of cross-talk cancellation in this network and show that the cross-talk interference cannot be removed well. For this reason, we design space-time codes by utilizing the cross-talk signals instead of removing them. In the other case, the self-coding is realized individually through the loop channel at each relay node and the signals from the two relay nodes form a space-time code. The achievable cooperative diversity of both cases is investigated and the conditions to achieve full cooperative diversity are presented. Simulation results verify the theoretical analysis.

4-Gb/s Parallel Receivers With Adaptive FEXT Cancellation by Pulse Width and Amplitude Calibrations

Two 4-Gb/s parallel receivers with adaptive far-end crosstalk (FEXT) cancellation are presented, which requires a calibration mode. A digitally controlled high-pass filter and a variable-gain amplifier are used to generate the crosstalk cancellation (XTC) signal. The pulse width and amplitude of the XTC signal are automatically calibrated to match the FEXT signal for different channel spacing. It is expected to minimize the residual FEXT signal. Two receivers using the proposed adaptive XTC are fabricated in 40-nm CMOS technology and the core area occupies 0.045 mm2. The power consumption from a 0.9-V supply is 19.8 mW. For two 4-Gb/s PRBS of 27 - 1 passing through FR4 PCB traces with 5-in long and 8-mil spacing, the measured peak-to-peak jitter of data is reduced by 27.78 ps by using the proposed adaptive XTC.

Extension of the crosstalk cancellation method in ultrasonic transducer arrays from the harmonic regime to the transient one

This paper describes a procedure to extend the crosstalk correction method presented in a previous paper [A. Bybi, S. Grondel, J. Assaad, A.–C. Hladky-Hennion, M. Rguiti, Reducing crosstalk in array structures by controlling the excitation voltage of individual elements: a feasibility study, Ultrasonics, 53 (6) (2013) 1135–1140] from the harmonic regime to the transient one. For this purpose a part of an ultrasonic transducer array radiating in water is modeled around the frequency 0.5MHz using the finite element method. The study is carried out at low frequency in order to respect the same operating conditions than the previous paper. This choice facilitated the fabrication of the transducer arrays and the comparison of the numerical results with the experimental ones. The modeled array is composed of seventeen elements with the central element excited, while the others are grounded. The matching layers and the backing are not taken into account which limits the crosstalk only to the piezoelectric elements and fluid. This consideration reduces the structure density mesh and results in faster computation time (about 25min for each configuration using a computer with a processor Intel Core i5-3210M, frequency 2.5GHz and having 4Go memory (RAM)).The novelty of this research work is to prove the efficiency of the crosstalk correction method in large frequency band as it is the case in medical imaging. The numerical results show the validity of the approach and demonstrate that crosstalk can be reduced by at least 13dB in terms of displacement. Consequently, the directivity pattern of the individual element can be improved.

A 5 Gb/s Single-Ended Parallel Receiver With Adaptive Crosstalk-Induced Jitter Cancellation

This paper presents an adaptive far-end crosstalk cancellation scheme for a single-ended parallel receiver. The adaptation engine is embedded in a single representative channel CDR, and the receiver efficiently reduces the crosstalk noise with a minimal cost in hardware and power consumption. In addition, the proposed scheme can be applied to any given CDR and equalizing circuits. The receiver is fabricated in 0.13 μm CMOS technology and achieves a reduction of FEXT-induced jitter up to 75%. The receiver consumes 65 mW at 5 Gb/s (4.3 mW/Gb/s/pin) including a PLL for global clock distribution.

G.fast: evolving the copper access network

Continuous improvements in communication technologies over copper pair access networks have enabled hybrid fiber/copper access networks that provide ever increasing broadband data rates. Most recently, field trials have demonstrated that crosstalk cancellation, also referred to as vectoring, and bonding two pairs to push data rates of very high speed DSL above 100 Mb/s on a single copper pair and above 200 Mb/s on two copper pairs. Looking ahead, the G.fast project group of the ITU-T is currently defining a new copper access technology to provide aggregate (upstream and downstream) data rates of up to 1 Gb/s over distances up to 250 m. This article provides an overview of some key challenges that need to be addressed for G.fast.

Comparison of head-related impulse response measurement approaches

The well-established static head-related transfer function (HRTF) measurement approaches using maximum length sequences and sine sweeps are compared with a recent HRTF estimation approach using normalized least mean square adaptive filters, which enables a continuous movement of the person to be measured during the recording of the excitation signal. By using continuous movement HRTF measurement, a huge amount of time for the individual HRTF estimation can be saved to create a dense HRTF database for headphone-based sound synthesis or applications such as crosstalk cancellation for loudspeaker-based sound synthesis. The different approaches are implemented and experimentally compared by objective and subjective evaluation.

Position-Dependent Crosstalk Cancellation Using Space Partitioning

The present study tested a new stereo playback system that effectively cancels cross-talk signals at an arbitrary listening position. Such a playback system was implemented by integrating listener position tracking techniques and crosstalk cancellation techniques. The entire listening space was partitioned into a number of non-overlapped cells and a crosstalk cancellation filter was assigned to each cell. The listening space partitions and the corresponding crosstalk cancellation filters were constructed by maximizing the average channel separation ratio (CSR). Since the proposed method employed cell-based crosstalk cancellation, estimation of the exact position of the listener was not necessary. Instead, it was only necessary to determine the cell in which the listener was located. This was achieved by simply employing an artificial neural network (ANN) where the time delay to each pair of microphones was used as the ANN input and the ANN output corresponded to the index of cells. The experimental results showed that more than 95% of the experimental listening space had a CSR ≥ 10 dB when the number of clusters exceeded 12. Under these conditions, the correlation between the true directions of the virtual sound sources and the directions recognized by the subjects was greater than 0.9.

A 12-Gb/s Multichannel I/O Using MIMO Crosstalk Cancellation and Signal Reutilization in 65-nm CMOS

A crosstalk cancellation and signal reutilization (XTCR) analog front-end implemented with infinite impulse response (IIR) networks dramatically improves signal integrity across multiple closely-spaced single-ended PCB traces. The XTCR technique has been designed to address multiple high-speed I/Os from the ground up. To verify this technique a 4 channel prototype was implemented in 65 nm CMOS. This 4 channel prototype design handles crosstalk cancellation for single-ended I/Os operating at 12 Gb/s. At this speed, the prototype XTCR design improves the measured average horizontal and vertical-eye openings by 37.5% and 26.4% at 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> BER, while consuming only 0.96 pJ/b/lane.

4-Gb/s Parallel Receivers With Adaptive Far-End Crosstalk Cancellation

Two 4-Gb/s parallel receivers with adaptive far-end crosstalk (FEXT) cancellation are presented. By using the highpass filter, the crosstalk cancellation (XTC) signal is generated to compensate the FEXT signal. A power detection loop is adopted to achieve automatic tuning of the XTC coefficient for different channel spacing. The receivers with adaptive XTC are fabricated in 40-nm CMOS technology, and the core area occupies 0.0229 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The maximum power consumption from a 1.2-V supply is 15.6 mW. For two 4-Gb/s pseudorandom binary sequences of 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> -1 passing through FR4 printed circuit board traces with 5-in length and 8-mil spacing, the measured peak-topeak jitter of the data is reduced by 32.22 ps by using the adaptive XTC. The measured adaptation time of the power detection loop is 63.44 μs.

Sound localization in individualized and non-individualized crosstalk cancellation systems

The sound-source localization provided by a crosstalk cancellation (CTC) system depends on the head-related transfer functions (HRTFs) used for the CTC filter calculation. In this study, the horizontal- and sagittal-plane localization performance was investigated in humans listening to individualized matched, individualized but mismatched, and non-individualized CTC systems. The systems were simulated via headphones in a binaural virtual environment with two virtual loudspeakers spatialized in front of the listener. The individualized mismatched system was based on two different sets of listener-individual HRTFs. Both sets provided similar binaural localization performance in terms of quadrant, polar, and lateral errors. The individualized matched systems provided performance similar to that from the binaural listening. For the individualized mismatched systems, the performance deteriorated, and for the non-individualized mismatched systems (based on HRTFs from other listeners), the performance deteriorated even more. The direction-dependent analysis showed that mismatch and lack of individualization yielded a substantially degraded performance for targets placed outside of the loudspeaker span and behind the listeners, showing relevance of individualized CTC systems for those targets. Further, channel separation was calculated for different frequency ranges and is discussed in the light of its use as a predictor for the localization performance provided by a CTC system.

Reducing crosstalk in array structures by controlling the excitation voltage of individual elements: A feasibility study

This paper describes a procedure to minimize crosstalk between the individual elements of a piezoelectric transducer array. A two-dimensional finite elements model was developed and the excitation voltages predicted by the model were applied to the array prototypes made of PZT 27 ceramic. Symmetric and asymmetric linear phased arrays operating at approximately 450kHz were tested in the feasibility study. The studies were carried out at low frequency to facilitate the fabrication of the transducer arrays and to check the feasibility in this case. The novelty of our approach is to offer active cancellation of crosstalk in transducer arrays generating continuous waves, even in the presence of fabrication defects.The experimental results showed the validity of the approach and demonstrated that crosstalk can be reduced by about 6–10dB. In ultrasonic imaging systems, this method could be introduced by using a multichannel generator providing electrical signals containing both phased signals required to focalize and deflect the acoustic beam associated with the correction signals.

Multichannel massive audio processing for a generalized crosstalk cancellation and equalization application using GPUs

Multichannel acoustic signal processing has undergone major development in recent years due to the increased complexity of current audio processing applications, which involves the processing of multiple sources, channels, or filters. A general scena

Nonlinear cross-talk mitigation in polychromatic parametric sampling gate

New technique for cancellation of nonlinear cross-talk in polychromatic parametric sampling gate is described and quantified. The method relies on a newly derived look-up table method that achieves equalization and suppresses nonlinear response associated with parametric sampling operation. The new cancellation scheme is implemented in a framework of a specific parametric photonics assisted analog-to-digital conversion (ADC) copy-and-sample-all (CaSA) architecture. A 20 dB improvement in total harmonic distortion is demonstrated experimentally.

A 7.5-Gb/s One-Tap-FFE Transmitter With Adaptive Far-End Crosstalk Cancellation Using Duty Cycle Detection

A 2.5-7.5-Gb/s transmitter with one-tap feed-forward equalizer (FFE) and adaptive far-end crosstalk (FEXT) cancellation is presented. To cancel the intersymbol interference, the one-tap FFE is also employed. A crosstalk canceller (XTC) is adapted to cancel FEXT by using inverse pulses. To cancel the FEXT due to the coupled microstrip lines with various spacing, the pulse amplitude of the XTC is digitally controlled by using the proposed duty cycle detection. The one-tap FFE and the XTC are merged together to save the power. This adaptive transmitter is fabricated in a 65-nm CMOS technology. The maximum power consumption from a 1.2-V supply is 26.4 mW, and the core area occupies 0.0307 mm2 . For two 5-in FR4 printed-circuit-board traces with the spacing of 8 mil, the measured rms and peak-to-peak jitters of the recovered data are improved by 10.01 and 48.9 ps, respectively, for a 7.5-Gb/s PRBS of 27 -1 . The measured calibration time of the XTC is 1.17 μs.

Demonstration of four-wave-mixing induced crosstalk cancellation in 10-Gbit/s phase locked multi-carrier OOK signals transmission

This paper demonstrated four-wave mixing induced crosstalk cancellation in 10Gbit/s OOK signal phase locked multi-carrier transmission. Successful transmission over dispersion-shifted fiber was achieved within 1dB power penalty even though the crosstalk was -15dB.