Search results for "Communication channel"

A Tracking and Timing (t-and-t) Front-end Electronics For Rpc Detectors

1992

Abstract The availability of a detector such as an RPC (resistive plate counter) opens new possibility on the future experiments for accelerator and non-accelerator physics. The main advantage consists on the possibility to obtain accurate tracking and timing with a low-cost detector and electronics. We report results on time resolution, signal transmission on long strips, efficiency and maintenance. A possible front-end electronics able to give tracking and timing information on each input channel operating in free-running mode will be illustrated toghether to the preliminary tests performed.

Limits of ultra-high bit rate RZ data transmissions in terrestrial optical fiber systems

2006

We numerically study the limits of the terrestrial optical fiber systems as a function of the bit rate. In particular, we compare for 160-, 320- and 640-Gbit/s the limits of single channel and WDM configurations.

Optical turbulence measurements and channel modeling of an indoor Free Space Optics link

2014

Turbulent Superfluid Profiles and Vortex Density Waves in a Counterflow Channel

2012

In this paper we study the two-dimensional profiles of the superfluid component velocity and the quantized vortex-points density in a counterflow channel where the influence of the walls cannot be neglected. The numerical results obtained show the presence of vortex density waves in the channel, as shown in a recent paper by means of the one-fluid model.

Prediction of Swirling Flow in a Corrugated Channel

1991

Laminar and turbulent flow in a corrugated channel is simulated using HARWELL-FLOW3D. The channel represents a typical cell within a proposed design for the heat-transfer element of a rotary regenerator. Velocity vectors in planes perpendicular and parallel to the axis of a corrugation are visualised using Harwell’s graphics package, OUTPROC. Both programs were mn on Harwell’s Cray 2. The velocity vector plots show clear evidence of swirl, which is thought to be the mechanism responsible for the high rates of heat transfer in this type of heat-exchanger geometry. The swirl strength is shown to be a function of the channel geometry.

Simple non-Markovian microscopic models for the depolarizing channel of a single qubit

2012

The archetypal one-qubit noisy channels ---depolarizing, phase-damping and amplitude-damping channels--- describe both Markovian and non-Markovian evolution. Simple microscopic models for the depolarizing channel, both classical and quantum, are considered. Microscopic models which describe phase damping and amplitude damping channels are briefly reviewed.

A Method Based on Amplitude Probability Density Representation for Sounding High Frequency Noise in Ionospheric Channels

2021

High Frequency (HF) communications efficiency require a precise characterization of the ionospheric channel’s noise. We present a rapid and accurate method to sound the HF ionospheric channels that enables tracing of the time-availability of the channel based on imposed electric field strength thresholds. The method makes use of the amplitude probability density implemented in a real-time spectrum analyzer. Sounding of 3, 10 and 20 kHz bandwidth channels in the 4.8 – 8.8 MHz range is exemplified and specific observations are presented.

Correlation and Spectral Properties of Vehicle-to-Vehicle Channels in the Presence of Moving Scatterers

2013

This paper derives a vehicle-to-vehicle (V2V) channel model assuming a typical propagation scenario in which the local scatterers move with random velocities in random directions. The complex channel gain of the proposed V2V channel model is provided. Subsequently, for different scatterer velocity distributions, the corresponding autocorrelation function (ACF), power spectral density (PSD), and the Doppler spread of the channel are derived, shown, and confirmed by the available measurement data. It is shown that the Gaussian mixture (GM) and the exponential distribution can accurately describe the velocity distribution of relatively fast and slow moving scatterers, respectively. Since the p…

Performance Comparison of SSMF and UltraWave Fibers for Ultra-Long-Haul 40-Gb/s WDM Transmission

2007

International audience; We experimentally compare the performance of standard single-mode fiber (SSMF) and UltraWave fiber (UWF) for ultra-long-haul (ULH) 40-Gb/s wavelength-division-multiplexing transmissions. We used the carrier-suppressed return-to-zero amplitude-shift-keying (CSRZ-ASK) and the carrier-suppressed return-to-zero differential-phase-shift-keying (CSRZ-DPSK) formats, which are particularly well-adapted to 40-Gb/s pulse-overlapped propagation. We demonstrate that transmission distance well beyond 2000 km can be reached on UWF with both the CSRZ-ASK and CSRZ-DPSK formats, or on SSMF with the CSRZ-DPSK format only, thus indicating that SSMF-based infrastructure of incumbent car…

A study on the distribution of the envelope and the capacity of underwater acoustic channels

2014

This paper deals with the statistical analysis of the instantaneous capacity of shallow underwater acoustic communication (UWAC) channels under the assumption that the scatterers are randomly distributed on the surface and bottom of the ocean. We start by deriving exact closed-form expressions for the probability density function (PDF) of the total propagation path length from which the PDF of the path gains is obtained. Then, we study the distributions of the channel envelope and the capacity under line-of-sight (LOS) conditions. By performing the chi-square goodness-of-fit test, it is shown that the channel envelope is Rice distributed. Moreover, we investigate the effect of the ocean dep…