A universal two-way approach for estimating unknown frequencies for unknown number of sinusoids in a signal based on eigenspace analysis of Hankel matrix

We develop a novel approach to estimate the \(n\) unknown constituent frequencies of a noiseless signal that comprises of unknown number, \(n\), of sinusoids of unknown phases and unknown amplitudes. The new two-way approach uses two constraints to accurately estimate the unknown frequencies of the sinusoidal components in a signal. The new approach serves as a verification test for the estimated unknown frequencies through the estimated count of the unknown number of frequencies. The Hankel matrix, of the time domain samples of the signal, is used as a basis for further analysis in the Pisarenko harmonic decomposition. The new constraints, the existence factor and the component factor, have been introduced in the methodology based on the relationships between the components of the sinusoidal signal and the eigenspace of the Hankel matrix. The performance of the developed approach has been tested to correctly estimate any number of frequencies within a signal with or without a fixed unknown bias. The method has also been tested to accurately estimate the very closely spaced low frequencies.     

On the duality between array beam-formers and MU-MISO precoders

Telecommunication Systems - Multi-user transmission, whereby users share time and frequency resources has been an active research area in the past decade in which the uniform linear array (ULA) was...     

A band‐suppression UWB suspended planar antenna incorporating a slotted spiral resonator

A novel miniaturized planar inverted F‐L antenna assembly is considered for UWB radio operations. The antenna design utilizes the electromagnetic coupling between an air dielectric planar inverted‐F antenna (PIFA) and a parasitic planar inverted‐L (PIL) element, with broadband feeding from a rectangular plate. To improve the functionality of the channel, a simple notch filter has been introduced through a local modification to the broadband feed plate, this takes the form of a simple slotted rectangular spiral resonator which is etched directly onto the plate. This allows the proposed antenna to maintain its full band UWB coverage, with the HYPERLAN/2 band centered at 5.35 GHz to be effectively rejected over the sub‐band 5.15–5.725 GHz, without the need for substantial re‐optimization of its principal structure parameters. The impedance bandwidth operates over the full UWB band, with VSWR better than 2, this performance is not degraded by the presence of the band rejection. The observed gains, radiation patterns, and group delay confirm that the antenna has appropriate characteristics for short range wireless applications. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Monitoring of flowing charges with an electrostatic voltmeter

This paper describes a simple method of monitoring the net electric charge of powders transported pneumatically through a dielectric pipe. An electrostatic voltmeter (ESVM) is used to measure the voltage induced on an isolated ring electrode placed on the outside surface of the pipe. An equivalent circuit model of the measurement system was constructed and experimentally verified using an electrophotographic toner and an aluminum oxide powder (Al/sub 2/O/sub 3/). Knowledge of the voltage induced by flowing charged particles on the electrode allows for the calculation of the total charge that flew through the pipe. However, in order to obtain an accurate voltage measurement, the input impedance of the instrument used for that purpose must be very high. The high impedance of an ESVM makes it uniquely suited for this application.     

Minerals-based sustainable development — One viable alternative

Anti-mining sentiments are rife in Europe and North America. Environmental accidents associated with mining activities in numerous countries and resource wars in Africa have triggered harsh criticism, not only of mining but also of the metal industries in general. The purpose of this article is to discuss mining industry practices and responsibilities and to consider the options available for using mineral wealth as a lever for economic, social and cultural development. Our conclusions are that not only are minerals indispensable to such development, but possibly the only viable alternative for a better global standard of living. The article is organised into four sections: 1. First, the back ground to the current situation is reviewed; 2. The sustainability concept as applied to mining is discussed; 3. Transnational mining companies are key players and the target of much of the criticism and their role is analysed in the third section; 4. We consider the issue of poverty reduction and resources development.     

New multi‐standard dual‐wideband and quad‐wideband asymmetric step impedance resonator filters with wide stop band restriction

New multi‐standard wide band filters with compact sizes are designed for wireless communication devices. The proposed structures realize dual‐wideband and quad‐wideband characteristics by using a new skew‐symmetrical coupled pair of asymmetric stepped impedance resonators, combined with other structures. The first and second dual‐wideband filters realize fractional bandwidths (FBW) of 43.2%/31.9% at the central frequencies (CF) of 1.875/1.63 GHz, and second bandwidths of 580 MHz/1.75 GHz at CF of 5.52/4.46 GHz, respectively. The proposed quad‐band filter realizes its first/second/third/fourth pass bands at CF 2.13/5.25/7.685/9.31 GHz with FBW of 46.0%/11.4%/4.6% and 5.4%, respectively. The wide pass bands are attributed to the mutual coupling of the modified ASIR resonators and their bandwidths are controllable by tuning relative parameters while the wide stop band performance is optimized by the novel interdigital cross coupled line structure and parallel uncoupled microstrip line structure. Moreover, the quad band is generated by introducing the novel defected rectangle structure. These multi‐standard filters are simulated, fabricated and measured, and measured results agree well with both simulated results and theory predictions. The good in‐band and out‐of‐band performances, the miniaturized sizes and simple structures of the proposed filters make them very promising for applications in future multi‐standard wireless communication.     

Comparison of ultrasonographic results of the breast with progesterone levels in women with fibrocystic mastopathy

Measuring the level of progesterone in 80 women who according to the ultrasound images had fibrocystic mastopathy. I've concluded by comparing the ultrasound images with the measurement of hormones that there was conformity of 75%.     

Conrad's rule for phase-modulation spectra

A simple two parameter expression is derived for the spectral density resulting from phase modulation by a Gaussian signal. The effective bandwidth is not as given by Conrad's rule.