Number of found documents: 478
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Notes to multistage Wiener filter in DS-CDMA detector
Šimša, Jan
2010 - English
The contribution follows report oriented towards design of Wiener filter in DS-CDMA detector of signals as a multistage structure. Such approach avoids evaluation of the inverse of a known autocorrelation matrix of a sampled response of the chip matched filter to a wide-sense stationary input signal. The contribution gives more detailed description of detector signal processing and its consequences. Keywords: CDMA; multiuser detector; interference Available at various institutes of the ASCR
Notes to multistage Wiener filter in DS-CDMA detector

The contribution follows report oriented towards design of Wiener filter in DS-CDMA detector of signals as a multistage structure. Such approach avoids evaluation of the inverse of a known ...

Šimša, Jan
Ústav fotoniky a elektroniky, 2010

IMPROVING UNIT CONCATENATIONS IN EXPERIMENTAL SPEECH SYNTHESIS BASED UPON COMPLEX CEPSTRUM IN THE CONCATENATION-BASED TTS SYSTEM EPOS
Staněk, Jan
2010 - English
During testing phase of a new speech analysis and synthesis methods based upon complex cepstrum and implemented in a TTS system Epos, we have discovered disturbing speech artifacts on the borders of the concatenated units. To eliminate these artifacts, we have chosen to practically implement and test usage of smoothing algorithms in the cepstral domain and observe its impact on the resulting synthesized speech. The results of our tests are presented in this paper. Keywords: analysis of speech; speech synthesis Available at various institutes of the ASCR
IMPROVING UNIT CONCATENATIONS IN EXPERIMENTAL SPEECH SYNTHESIS BASED UPON COMPLEX CEPSTRUM IN THE CONCATENATION-BASED TTS SYSTEM EPOS

During testing phase of a new speech analysis and synthesis methods based upon complex cepstrum and implemented in a TTS system Epos, we have discovered disturbing speech artifacts on the borders of ...

Staněk, Jan
Ústav fotoniky a elektroniky, 2010

Surface plasmon resonance biosensors: present and future
Homola, Jiří
2010 - English
Optical biosensors based on the surface plasmon resonance (SPR) have become important tool for real-time study of biomolecular interactions and for detection of various analytes in fields such as food safety, medical diagnostics, or environmental monitoring. This paper reviews the present state of the art in the development of SPR sensor technology, discusses emerging trends, and presents selected results of research into SPR sensors at the Institute of Photonics and Electronics, Prague. Keywords: Surface plasmon resonance imaging; Biosensor; Protein detection Available at various institutes of the ASCR
Surface plasmon resonance biosensors: present and future

Optical biosensors based on the surface plasmon resonance (SPR) have become important tool for real-time study of biomolecular interactions and for detection of various analytes in fields such as food ...

Homola, Jiří
Ústav fotoniky a elektroniky, 2010

Vláknové lasery
Peterka, Pavel
2010 - Czech
Vláknové lasery patří mezi nejpůsobivější úspěchy fotoniky posledních let. Poskytují hrubou sílu využitelnou pro řezání a sváření v průmyslu, ale lze je nalézt i v delikátních zařízeních vyvíjených pro dosud nejpřesnější měření frekvence a času. V příspěvku jsou uvedeny základní principy činnosti vláknových zesilovačů a laserů, některé jejich aplikace a vybrané výsledky výzkumu v tomto oboru v Ústavu fotoniky a elektroniky AV ČR, v.v.i. Fiber lasers are one of the most spectacular achievements of contemporary optoelectronics and photonics. Variety of fiber lasers were demonstrated ranging from mighty continuous-wave systems with multi-kilowatt output powers to elegant femtosecond-pulse sources for precise frequency and time measurements. In the contribution, we present basic principles and applications of these new sources of laser radiation and we present selected research results in this field in the Institute of Photonics and Electronics. Keywords: fiber laser; fiber amplifiers; optical fibers Available at various institutes of the ASCR
Vláknové lasery

Vláknové lasery patří mezi nejpůsobivější úspěchy fotoniky posledních let. Poskytují hrubou sílu využitelnou pro řezání a sváření v průmyslu, ale lze je nalézt i v delikátních zařízeních vyvíjených ...

Peterka, Pavel
Ústav fotoniky a elektroniky, 2010

ZnO NANOPARTICLES AND THEIR APPLICATIONS – NEW ACHIEVMENTS
Nohavica, Dušan; Gladkov, Petar
2010 - English
The advantages of ZnO are a low price, good gas sensing properties, photocatalytic activity, antibacterial activity, possibility to prepare structures with interesting optical properties, like photonic crystals, catalytic materials etc. In our laboratory the special research type of MOCVD apparatus has been developed. In the study we have investigated the influence of the growth rate on the morphology of ZnO deposited on Si (100), GaP (111) as well as nanoporous GaP. The same apparatus has been used for ZnO nanoparticles preparation with the diameter of individual nanoparticles of about 25 nm. Keywords: ZnO; MOCVD; Applications development ZnO Available at various institutes of the ASCR
ZnO NANOPARTICLES AND THEIR APPLICATIONS – NEW ACHIEVMENTS

The advantages of ZnO are a low price, good gas sensing properties, photocatalytic activity, antibacterial activity, possibility to prepare structures with interesting optical properties, like ...

Nohavica, Dušan; Gladkov, Petar
Ústav fotoniky a elektroniky, 2010

Silica optical microresonators
Jelínek, M.; Todorov, Filip; Matějec, Vlastimil; Chomát, Miroslav; Kubeček, V.; Berková, Daniela
2010 - English
The paper deals with the preparation of spherical silica microresonators by melting silica optical fiber with an oxygen-hydrogen flame. Resonant spectra of prepared spherical silica microresonators suitable for telecommunications and sensors purposes are also presented. Keywords: optical microresonator; communications; sensing Available at various institutes of the ASCR
Silica optical microresonators

The paper deals with the preparation of spherical silica microresonators by melting silica optical fiber with an oxygen-hydrogen flame. Resonant spectra of prepared spherical silica microresonators ...

Jelínek, M.; Todorov, Filip; Matějec, Vlastimil; Chomát, Miroslav; Kubeček, V.; Berková, Daniela
Ústav fotoniky a elektroniky, 2010

METALIC NANOPARTICLES AND NANOSTRUCTURES
Nohavica, Dušan
2010 - English
A brief overview of the field of metallic nanoparticles and nanocrystalline materials preparation and their properties is presented. Dependence of the chemical potential on surface curvature is important for particles solubility in the melt, vapour pressure of liquids as a function of droplet radius, Ostwald ripening and sintering of the individual particles. Melting point and lattice constant depends on the radius of nanoparticles as well. The major processing for nanocrystalline materials production includes chemical reaction, vapour condensation, electrodeposition, ball grinding, SPD etc. Keywords: nanocrystalline material; metallic material Available on request at various institutes of the ASCR
METALIC NANOPARTICLES AND NANOSTRUCTURES

A brief overview of the field of metallic nanoparticles and nanocrystalline materials preparation and their properties is presented. Dependence of the chemical potential on surface curvature is ...

Nohavica, Dušan
Ústav fotoniky a elektroniky, 2010

Electric field generated by higher vibration modes of microtubule
Cifra, Michal; Havelka, D.; Kučera, Ondřej; Pokorný, Jiří
2010 - English
Certain structures in a living cell may generate electric oscillations. Microtubules, which form a part of a cellular skeleton, belong to this class of structures and ful-fill all conditions for generation of electric oscillations in kHz÷GHz band. We present selected results from calculations of the oscillatory electric field generated by higher vibration modes of microtubules. We propose that the electric field of certain modes may play specific function in cellular organization Keywords: Bioelectromagnetism; Microtubules; Polar vibration modes Available at various institutes of the ASCR
Electric field generated by higher vibration modes of microtubule

Certain structures in a living cell may generate electric oscillations. Microtubules, which form a part of a cellular skeleton, belong to this class of structures and ful-fill all conditions for ...

Cifra, Michal; Havelka, D.; Kučera, Ondřej; Pokorný, Jiří
Ústav fotoniky a elektroniky, 2010

Complex Cepstrum in Speech Synthesi
Vondra, Martin; Vích, Robert
2010 - English
In the contribution the use of the complex cepstrum in speech modeling and synthesis is shortly described. The obtained mixed phase parametric speech model is of the finite impulse response type and contains also information about the phase properties of the modeled speech frame. The synthesized speech is more natural, but the memory requirements and numerical complexity are much higher than for minimum phase realization. Keywords: speech analysis; speech synthesis Available in a digital repository NRGL
Complex Cepstrum in Speech Synthesi

In the contribution the use of the complex cepstrum in speech modeling and synthesis is shortly described. The obtained mixed phase parametric speech model is of the finite impulse response type and ...

Vondra, Martin; Vích, Robert
Ústav fotoniky a elektroniky, 2010

STUDY OF ELECTROPHORETIC DEPOSITION OF Pd METAL NANOPARTICLES ON InP AND GaN CRYSTAL SEMICONDUCTORS FOR H2 GAS SENSORS
Žďánský, Karel; Yatskiv, Roman; Grym, Jan; Černohorský, O.; Zavadil, Jiří; Kostka, František
2010 - English
Deposition of Pd nanoparticles (NPs) on InP or GaN single crystal wafer was performed from isooctane colloid solution. Diodes were prepared by making Schottky contact with colloidal graphite on Pd NPs partly coated surface and ohmic contact on the blank side of the wafer. It was found that several ppb of hydrogen in nitrogen gas can be detected by monitoring the change of diode current at a constant bias voltage. Diodes made on GaN were about ten times more sensitive to hydrogen than those made on InP. Keywords: semiconductor devices; nanostructures; sensors Available at various institutes of the ASCR
STUDY OF ELECTROPHORETIC DEPOSITION OF Pd METAL NANOPARTICLES ON InP AND GaN CRYSTAL SEMICONDUCTORS FOR H2 GAS SENSORS

Deposition of Pd nanoparticles (NPs) on InP or GaN single crystal wafer was performed from isooctane colloid solution. Diodes were prepared by making Schottky contact with colloidal graphite on Pd NPs ...

Žďánský, Karel; Yatskiv, Roman; Grym, Jan; Černohorský, O.; Zavadil, Jiří; Kostka, František
Ústav fotoniky a elektroniky, 2010

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