Barkhausen noise emissions occur in ferromagnetic materials on application of a time varying external magnetic field. These emissions primarily occur because of the movement of domain walls in the presence of pinning sites or discontinuities, which act as inhibitors to domain wall motion with in the material. The emissions can be sensed using an induction coil placed close to the sample surface...

Introduction It is well known that surface coil arrays can increase the signal-to-noise ratio (SNR) in magnetic resonance spectroscopy (MRS) studies by performing a proper combination of the individual signals. Although it has been shown that electric and magnetic coupling mechanisms produce correlated noise in the coils [1], previous algorithms developed for MRS data combination have ignored t...

Introduction: Functional MRI methods have been used to study sensorimotor processing in the Spinal cord. However, these techniques confront unwanted contributions to the measured signal from the physiological fluctuations. For the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise, especi...

Magnetic resonance (MR) acoustic scanner noise may negatively affect the performanceof functional magnetic resonance imaging (±MRI), a problem that worsens at the higher field strengths proposed to enhance ±MRI. We present an overview of the current knowledge on theeffects of confounding acoustic MR noise in fMRI experiments. The principles and effectivenessof various methods to red...

The compound behavior of the magnetic recording channel is modeled by combining the Lorentzian read-back pulse, the microtrack channel model, and additive white Gaussian noise (AWGN). By noting that at the output of this model the read-back signal is cyclostationary, the average autocorrelation function and corresponding power spectral density over one period are computed. The average power spe...

An automated system for electronic noise measurements on metal films is presented. This new system, controlled by a personal computer which utilizes National Instruments’ LabVIEW software, is designed to measure low frequency noise as a function of an externally imposed magnetic field and as a function of a dc bias current in low-ohmic samples and magnetic sensors. With this system we are able ...

The main topic of this paper is to examine the impact on induction machine magnetic noise of a new stator magnetic circuit design. This new design was developed in order to increase AC machine energetic performance by assembling non-segmented shifted grainoriented steel sheets which make it possible to reduce iron losses. Experimental results on induction machine efficiency increase are present...

The spectrum of temporal fluctuations of total magnetic energy for several dynamo models is different from white noise at frequencies smaller than the inverse of the turnover time of the underlying turbulent velocity field. Examples of this phenomenon are known from previous work, and we add in this paper simulations of the G O Roberts dynamo and of convectively driven dynamos in rotating spher...

Magnetic tomography is an ill-posed and ill-conditioned inverse problem since, in general, the solution is non-unique and the measured magnetic field is affected by high noise. We use a joint sparsity constraint to regularize the magnetic inverse problem. This leads to a minimization problem whose solution can be approximated by an iterative thresholded Landweber algorithm. The algorithm is pro...

This paper demonstrates the concept of an optical magnetometer for magnetocardiography. The magnetometer employs a standard Least-Mean-Squares (LMS) algorithm for heart magnetic field measurement within unshielded environment. Experimental results show that the algorithm can extract a weak heart signal from a much-stronger magnetic noise and detect the P, QRS, and T heart features and completel...