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 ...

background: the adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. the objective of this study was to evaluate the noise characteristics of compressors ...

the modulation response, relative intensity noise and frequency noise characteristics of qd lasers are investigated theoretically, in presence of an additional optical pumping. it is revealed that the modulation response of qd laser enhances under additional optical beam. by small signal analysis of the carriers' and photons' rates, it is proposed that by injecting excess carriers to ...

background: noise is one of the most important harmful agents in work environment. noise pollution in oil refinery industries is related to workers' health. this study aimed to determine the overall noise pollution of an oil refinery operation and its frequency analysis to determine the control plan for a vent noise in these industries. methods: this experimental study performed in control unit...

noise exposure is one of the main problems in petroleum industry. petroleum in dustry is a strategic industry in iran with large number of workers whom are exposed to different noise sources. identification and evaluation of this noise sources and reducing excessive noises are big issues in petroleum industry from point of occupational health. this descriptive-analytic study was performed in th...