Thesis (Ph.D.) - University of Birmingham, Dept of Electronic and Electrical Engineering.
Directivity patterns of the parametric array as the two ships took measurements in the inhomogeneous section of the oce an. Refer to Fig. 2 for the actual physical loca- tion of the ships. Parameter Estimation of an Inhomogeneous Medium by Scattered Electromagnetic Fields Using Nonlinear Optics and Wavelets Manisha Khulbe1, 2, *, Harish Parthasarathy3, and Malay R. Tripathy1 Abstract—The aim of this work is to study the parameter estimation of a nonlinear medium in terms of scattered electromagnetic by: 2. In case of high signal to noise ratio (SNR), it is found that the MSE can be increased by a factor V"i, where m is the number of sensors in the array, as compared to spatially white noise. Simple expressions comparing the asymptotic (for large amounts of data) bias, resulting fronl a small noise covariance perturbation, with the asymptotic Cited by: 4. PDF | On Jan 1, , Vladimir E. Ostashev and others published Acoustics in Moving Inhomogeneous Media, Taylor & Francis (). | Find, read and cite all the research you need on ResearchGate.
Sound wave propagation in a shallow water environment is complex due to e.g. the uncertainties of sound speed profile being inhomogeneous and imprecisely measured, the bottom reflections, etc. A parametric array (PA) loudspeaker is a highly directional audio source that might grant one's convenience if it is used with mobile devices. However, conventional PA loudspeakers is almost impossible to apply in mobile devices using a battery because of the large power consumption and large device size. In this study, a PA loudspeaker system (PALS) was fabricated and evaluated to show that. The fundamental characteristics of parametric sound in air are demonstrated in Fig. 2, Fig. ultrasound source, whose circular aperture is 10 cm in radius, radiates bifrequency waves of 38 kHz and 40 kHz with the same pressure amplitudes of p 0 = 50 Pa ( dB re. 20 μPa) at the source surface. Fig. 2 shows the axial pressure profiles of the primary waves and the parametric sound of . Noise Tutorial VI ~ Noise Measurements with a Spectrum Analyzer See last page for document information Abstract: With the exception of some solar radio bursts, the extraterrestrial emissions received on Earth’s surface are very weak. Noise places a limit on the minimum detection capabilities of a radio telescope and may mask or corrupt these weak.
A review is made of the basic principles of parametric receiver operation and of wave propagation in an inhomogeneous medium. A theoretical analysis is presented for the case of a signal wave source located on the axis of the parametric receiver in a weakly inhomogeneous medium. A potential problem of a parametric receiving array mounted on a mobile platform is the platform's radiated noise interference. This can severely limit the detection performance of the parametric receiving array and, hence, can possibly limit the parametric receiving array to a quiet (stationary) platform. Unknown Noise-MUSIC (UN-MUSIC) is a promising method of direction of arrival (DOA) estimation in unknown spatially correlated noise using sparse arrays composed of two widely separated sub-arrays. Select WIDEBAND BACKSCATTERING MEASUREMENTS USING A PARAMETRIC ARRAY. Book chapter Full text access. Select A PERTURBATIVE TECHNIQUE FOR THE TREATMENT OF THE NON-DISSIPATIVE SOUND WAVE EQUATION OF A WEAK CRITICAL INHOMOGENEOUS MEDIUM. technicians, researchers, and physical scientists will find the book insightful.