Noise measurement

About: Noise measurement is a research topic. Over the lifetime, 19776 publications have been published within this topic receiving 308180 citations.

PLC System Performance With AF Relaying

Abstract: The use of repeaters (relays) has recently been introduced in power line communication (PLC) systems for long-distance data transfer and thus, it becomes important to analyze the performance of relay based PLC systems. A simplified system model with distance dependent signal attenuation and additive white Gaussian noise may not cover all the factors affecting the data transfer, such as variation in amplitude (fading) and occurrence of impulsive noise. Hence, a more realistic system model with log-normal fading, distance dependent signal attenuation, and a Bernoulli-Gaussian impulsive noise is considered in this paper to study the end-to-end average bit error rate (BER) and the end-to-end average channel capacity of a PLC system equipped with amplify-and-forward (AF) relays. Approximate closed-form expressions of the end-to-end average BER for binary phase-shift keying and the average channel capacity for high signal-to-noise ratio are obtained. The performance of the PLC system with AF relays is found to be superior compared to that of a direct transmission PLC system for fixed transmission power.

Deep-level analysis in (AlGa)As—GaAs 2-D electron gas devices by means of low-frequency noise measurements

Abstract: Low-frequency noise of (AlGa)As-GaAs heterostructures grown by molecular-beam epitaxy was investigated. The temperature of the samples was varied between 100 and 400 K. In the frequency range from 1 Hz to 25 kHz noise spectra can be described as superposition of several generation-recombination (GR) noise components. Four deep levels (E = 0.40, 0.42, 0.54, 0.60 eV) were detected, three of which are in agreement with those measured independently by deep-level transient spectroscopy (DLTS).

Noise Characteristics of 3D Time-of-Flight Cameras

Abstract: Time-of-flight (TOF) cameras are based on a new technology that delivers distance maps by the use of a modulated light source. In this paper we first describe a set of experiments that we performed with TOF cameras. We then propose a noise model which is able to explain some of the phenomena observed in the experiments. The model is based on assuming a noise source that is correlated with the light source (shot noise) and an additional additive noise source (dark current noise). The model predicts well the dependency of the distance errors on the image intensity and the true distance at an individual pixel.

A new self-tuning algorithm for the frequency estimation of distorted signals

Abstract: This paper introduces a new self-tuning digital signal processing algorithm for local power system frequency deviation measurement. The algorithm is derived using the nonrecursive least error square technique accompanied with an updating procedure, which generally improves the algorithm properties: the measurement range; the immunity to a random noise; and the accuracy. The algorithm developed takes into account the components of the fundamental frequency, the second through the M-th harmonics and a decaying DC component, so it could be used for the real-time distorted signals frequency estimation as well as for the harmonics measurement. To demonstrate the efficiency of the algorithm proposed, the results of the computer simulated, experimentally obtained and real-life data records tests are presented. >