International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Fast Fourier Transform (FFT) converts digitally sampled time domain data into the frequency domain. This paper will provide an advanced introduction for the telemetry engineer to basic FFT theory and then present and explain the different user preprocessing options that are available when using the FFT. These options include: using windowing functions, “zero filling” for frequency data interpolation, and setting the frequency resolution of the FFT resultant spectrum,

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The GPS receiver based on software radio technology is a kind of general purpose GPS signal processing platform which makes use of advanced design ideas and advanced design tools nowadays. We used FPGA device and lots of necessary peripherals such as DSP and PCI controller in our design to promote flexibility and practicability effectively. Various fast acquisition means and accurate tracking algorithms could be realized, improved and validated on this platform, besides basic GPS receiver function.

This thesis describes a novel approach that utilizes a special property of the Hanning window to accurately detect the fundamental frequency of the data signal in the presence of harmonic and interharmonic interference. After obtaining the fundamental frequency, the same procedure is applied to all possible harmonics to be filtered for further analysis of the interharmonics. The proposed approach is validated using numerical tests. In the literature, different authors have shown the difficulty of extracting a synchronized sampling frequency from the analyzed signal and discussed the effect of deviation of the fundamental in the presence of harmonics. This thesis suggests a new approach to overcome the difficulties, even if the interharmonics present are in frequency bins near the fundamental. In order to perform the interharmonic analysis, the author followed the IEC standard draft signal processing recommendations, with the exception of using a weighted Hanning window instead of a rectangular window in order to minimize the effect of the spectral leakage, and to minimize the effect of interharmonics on the main harmonics.

Darbo tema: akies dažninės skiriamosios gebos priklausomybės nuo žiūros kampo tyrimas. Šiame darbe analizuojami akies inertiškumo ypatumai. Išnagrinėta mokslinės literatūros žmogaus regos, akies inertiškumo, akipločio klausimais. Išanalizuota žmogaus regėjimo sistema, regos fiziologija. Pristatoma akies skiriamoji geba, pateikta jos matematinė išraiška, akies inertiškumo pavyzdžiai. Atliktas tyrimas, kurio metu nustatoma akies dažninės skiriamosios gebos priklausomybė nuo žiūros kampo. Tyrime dalyvavo 36 žmonės. Tiriamieji suskirstyti į dvi: 10-25 ir 26-50 metų amžiaus grupes. Tyrime nustatyta, tiriamųjų dažninės skiriamosios gebos priklausomybė nuo žiūros kampo, apskaičiuoti vidutiniai tyrimo duomenų rezultatai, pateikti įvairūs, tyrimo eigoje išryškėję nukrypimai nuo vidurkio. Šie tyrimo duomenys pavaizduoti grafiškai. Analizuojant teorinę medžiagą pastebėta, kad Lietuvoje, tai mažai tyrinėta sritis. Gauti tyrimo rezultatai rodo, kad padarius didesnius, daug daugiau tiriamųjų, kriterijų, apimančius tyrimus, būtų galima gauti įdomių rezultatų. / The subject of the work is the investigation of the dependence of human eye frequency resolution on a viewing angle. The final work analysis the features of eye inertia. Scientific literature was studied to look into the issues of human’s eyesight, eye inertia and the range of vision. The system and physiology of human’s eyesight have been examined as well. The work introduces eye resolution and its mathematical expression, and gives inertia examples. The investigation has been carried out to determine the dependence of human eye frequency resolution on a viewing angle with 36 people participating in it. The people were divided into two groups according to their age: 10-25 and 26-50. The investigation has determined the people’s dependence of eye frequency resolution on a viewing angle. The average data of the results have been estimated and various deviations from the mean shown up during the investigation are graphically presented in the work. While studying the theoretical material it was noticed that this field is still a byway in Lithuania. The findings suggest that if deeper and more criteria spanning researches were carried out, more revealing results could be expected.

No description available.