The aim of this paper is to minimize output phase noise for the pure signal synthesis in the frequency synthesizers. For this purpose, first, an exact mathematical model of phase locked loop (PLL) based frequency synthesizer is described and analyzed. Then, an exact closed-form formula in terms of synthesizer bandwidth and total output phase noise is extracted. Based on this formula, the phase ...

The Green's function of the Poisson equation, and its spatial derivatives, lead to a family of wavelets specifically tailored to potential fields. Upward continuation of the field is seen to be identical to these wavelets' scale change operation. The maxima at all heights of the field's horizontal gradients are termed the field's multiscale edges. A multiscale edge's field strength variation an...

in order to the enhancement of the quality of speech corrupted by additive noise, a speech enhancement method has been put forward based on the combination of spectral subtraction and binary masking. spectral subtraction is a powerful method for removing noise from speech and binary masking provides essential elements to be used in monaural speech segregation. in the proposed combined method, f...

Sound is an effective exogenous factors which affecting human brain processing mechanisms. This research was quasi experimental study that was carried out among 70 students to evaluate the effect of sound frequency on human noise annoyance. Noise annoyance degree was measured during exposure to sound at various frequencies of 500, 1000, 2000, 4000 and 8000 Hz. Sound.exe software was used to det...

We use a dense seismic array composed of 5200 vertical geophones to monitor microseismicity in Long Beach, California. Poor signal-to-noise ratio due to anthropogenic activity is mitigated via downward-continuation of the recorded wavefield. The downward-continued data are continuously back projected to search for coherent arrivals from sources beneath the array, which reveals numerous, previou...

We develop the theoretical foundations, numerical algorithms and computer programs to retrieve the 3D geometry of a density interface from gridded gravity data. The solution depends on constraining assumptions on permissible density values. An integral equation is solved by a new method of local corrections to find the density interface. The method is efficient and does not require trial-and-er...

introduction: hearing loss is one of the most common occupational diseases. in most workplaces, workers are exposed to noise and solvents simultaneously, so the potential risk of hearing loss due to solvents may be attributed to noise.  in this study we aimed to assess the effect of exposure to mixed aromatic solvents on hearing in the absence of exposure to hazardous noise.   materials and met...