3 research outputs found
Modern Methods of Time-Frequency Warping of Sound Signals
Tato práce se zabĂ˝vá reprezentacĂ nestacionárnĂch harmonickĂ˝ch signálĹŻ s ÄŤasovÄ› promÄ›nnĂ˝mi komponentami. PrimárnÄ› je zaměřena na Harmonickou transformaci a jeji variantu se subkvadratickou vĂ˝poÄŤetnĂ sloĹľitostĂ, Rychlou harmonickou transformaci. V tĂ©to práci jsou prezentovány dva algoritmy vyuĹľĂvajĂcĂ Rychlou harmonickou transformaci. Prvni pouĹľĂvá jako metodu odhadu zmÄ›ny základnĂho kmitoÄŤtu sbĂranĂ© logaritmickĂ© spektrum a druhá pouĹľĂvá metodu analĂ˝zy syntĂ©zou. Oba algoritmy jsou pouĹľity k analĂ˝ze Ĺ™eÄŤovĂ©ho segmentu pro porovnánĂ vystupĹŻ. Nakonec je algoritmus vyuĹľĂvajĂcĂ metody analĂ˝zy syntĂ©zou pouĹľit na reálnĂ© zvukovĂ© signály, aby bylo moĹľnĂ© změřit zlepšenĂ reprezentace kmitoÄŤtovÄ› modulovanĂ˝ch signálĹŻ za pouĹľitĂ HarmonickĂ© transformace.This thesis deals with representation of non-stationary harmonic signals with time-varying components. Its main focus is aimed at Harmonic Transform and its variant with subquadratic computational complexity, the Fast Harmonic Transform. Two algorithms using the Fast Harmonic Transform are presented. The first uses the gathered log-spectrum as fundamental frequency change estimation method, the second uses analysis-by-synthesis approach. Both algorithms are used on a speech segment to compare its output. Further the analysis-by-synthesis algorithm is applied on several real sound signals to measure the increase in the ability to represent real frequency-modulated signals using the Harmonic Transform.
2D Audio Scene Analysis and Rendering in Multichannel Sound-Reproduction Systems
Tato práce se zabĂ˝vá podnÄ›ty, kterĂ© ve sluchovĂ© soustavÄ› ÄŤlovÄ›ka zpĹŻsobujĂ prostorovĂ© slyšenĂ a polohovacĂmi metodami, kterĂ© tÄ›chto podnÄ›tĹŻ vyuĹľĂvajĂ. PodrobnÄ›ji se zabĂ˝vá metodou vektorovÄ› bázovĂ©ho amplitudovĂ©ho polohovánĂ a metodou ambisonie. Na základÄ› popisu tÄ›chto metod byl realizován návrh a implementace ve formÄ› plug-in modulu systĂ©mu VST. Tato práce takĂ© obsahuje poslechovĂ˝ test ambisonie druhĂ©ho řádu a analĂ˝zu zĂskanĂ˝ch dat.This thesis deals with cues used by the human auditory system to identify the location of sound and methods for sound localisation based these cues, namely, vector based amplitude panning and ambisonics, which are described in detail. These methods have been implemented as a VST plug-in module. This thesis also contains listening tests of second order ambisonics along with acquired data analysis.
Efficient Spectral Estimation of Non-Stationary Harmonic Signals Using Harmonic Transform
Non-stationary harmonic signals cannot be accuratelyrepresented by Fourier transform (FT). Fortunately, severalmethods for representing non-stationary harmonic signalsexist including Fan-Chirp trasnform (FChT) or Harmonic transform(HT). This article is focused on the Harmonic transform andits computation. Estimation of slope of fundamental frequencychange between analysed segments is essential for computationof the HT. The slope is estimated using several realisations ofHT and comparing the spectral flatness. Optimisation of thisprocedure is presented in the article