The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Joon-hoon Park - One of the best experts on this subject based on the ideXlab platform.
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Design of wireless class-D Stereo Amplifier system using Bluetooth
2010Co-Authors: Joon-hoon Park, Byeong-ju KimAbstract:What with large volume and high power consumption, conventional audio Amplifier is not suitable for resent mobile IT devices such as PMP, MP3 and notebook PC but a class-D Amplifier is more appropriate for such mobile IT devices because a class-D Amplifier has various advantages in digital and compact circuit design. In addition, by applying Li-polymer secondary battery and Bluetooth technology to a class-D Amplifier, the system can be more portable and light. In this paper, a design and implementation method for wireless class-D Stereo Amplifier system is presented.
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design of mobile digital Stereo Amplifier system using tpa2008d2 secondary battery
ITC-CSCC :International Technical Conference on Circuits Systems Computers and Communications, 2008Co-Authors: Joon-hoon Park, Minkyu Park, Kiseo Lee, Younggyu ChoiAbstract:Existing audio power Amplifiers do not satisfy the requirement of recent digital products such as PMP and MP3 that requires mobility and miniaturization, because of large volume due to high power, and inconvenient transfer to direct connection back of power suply. To solve these problems, we designed class-D digital Stereo Amplifier to use TI’s TPA2008D2, which power dissipation and low caloric value. The second lithium ion polymer battery is applied and implemented for low electric power and high effectiveness mobile digital audio system. Designed digital audio system can fill up the battery through power adapter and USB port. We passed through efficient circuit pattern design process and analysis experiment about inside noise for stable digital audio system design. Also, we could improve the reliability of product development by using 3D digital Amplifier circuit, which is applicable to mobile digital audio system design.
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implementation of digital Stereo Amplifier for mobile it devices based on wireless communication system using bluetooth
International Conference on Future Generation Communication and Networking, 2007Co-Authors: Joon-hoon ParkAbstract:Bluetooth was started from concept that connected in all communication environments by single equipment integrating different communication devices. Wireless communications of today are using cellular phone, broadband wireless service, home RF, Bluetooth that supports data and voice and so on. Among these, Bluetooth is very useful wireless communication method. In this paper, a design and implementation method of wireless digital Amplifier for mobile IT devices is presented. Efficiency of analog Amplifier is low and it has disadvantage that do not attach cooling fan by noise of inside. Moreover external form size of analog Amplifier can't but be big because of heat sink. Therefore, analog Amplifier is not suitable to mobile IT device. And today, it is trend that most IT devices that have wireless communication functions.
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FGCN (2) - Implementation of Digital Stereo Amplifier for Mobile IT Devices Based on Wireless Communication System Using Bluetooth
Future Generation Communication and Networking (FGCN 2007), 2007Co-Authors: Joon-hoon ParkAbstract:Bluetooth was started from concept that connected in all communication environments by single equipment integrating different communication devices. Wireless communications of today are using cellular phone, broadband wireless service, home RF, Bluetooth that supports data and voice and so on. Among these, Bluetooth is very useful wireless communication method. In this paper, a design and implementation method of wireless digital Amplifier for mobile IT devices is presented. Efficiency of analog Amplifier is low and it has disadvantage that do not attach cooling fan by noise of inside. Moreover external form size of analog Amplifier can't but be big because of heat sink. Therefore, analog Amplifier is not suitable to mobile IT device. And today, it is trend that most IT devices that have wireless communication functions.
Dofek Přemysl - One of the best experts on this subject based on the ideXlab platform.
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Design of nf electron-valve Stereo Amplifier
Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011Co-Authors: Dofek PřemyslAbstract:This master’s thesis is dealing with low frequency all valve Stereo Amplifier unit conception for an electric guitar. The Amplifier contains two independent output stages with two power tubes EL34, working in AB class, with 40Watts of power. The apparatus is equipped with two channels, EQ correctors, parallel effects loop, output selection with lowered anode power supply, selection between silicon or tube rectifier. The preAmplifier works in mono mode and the Stereophony is reached by dividing the signal in an added effects system. This unusual solution differs from both monaural conceptions and binaural power Amplifiers which contains no preamp. It offers the possibility of Stereophony without the necessity of dividing the guitar signal before the Amplifier’s input. The sound that comes from the speaker on one side is effected and on the other side is dry by using monaural effects apparatus. The sound from both speakers is effected by using binaural effect apparatus. The Amplifier can be used as power Amplifier stage only when the return of the effect loop is used as the Amplifier input. Every available possible solution is discussed in case of each block and then the most suitable is chosen. The biggest attention is paid to a proposal and calculation of both power and output transformer, ergonomical lay-out of the stages in need of the best S/N separation. The stages were simulated in Micro-Cap 9.0 and Tonestack 1.3 computer programmes. The construction was carried out with the emphasis on proper shielding and grounding. The overall stability tests were performed after building the Amplifier as well as frequency characteristics with the scope and distortion with the distortion meter
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Design of nf electron-valve Stereo Amplifier
Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011Co-Authors: Dofek PřemyslAbstract:Tato diplomová práce se zabývá koncepcí nízkofrekvenčního elektronkového Stereofonního zesilovače pro elektrofonickou kytaru. Zesilovač obsahuje dva samostatné koncové stupně s elektronkami EL34 ve třídě AB o výkonu 40W. Je vybaven dvěma kanály, korekcemi, paralelní efektovou smyčkou, přepínáním výkonu pomocí sníženého anodového napětí, volbou elektronkového nebo diodového usměrňovače. Předzesilovač je monofonní a Stereofonie je dosaženo rozdělením signálu v efektové smyčce pomocí zařazeného efektu. Toto neobvyklé řešení se liší jak od klasických monofonních koncepcí, tak od Stereofonních koncových zesilovačů, které předzesilovače neobsahují. Poskytuje však uživateli možnost Stereofonie, aniž by musel dělit signál z nástroje ještě před vstupem zesilovače. Použitím monofonního efektového zařízení bude zvuk z reproboxu na jedné straně efektovaný, na druhé bez efektu, použitím Stereofonního efektového zařízení bude zvuk z reproboxů na obou stranách efektovaný. Zesilovač lze použít i jako čistě výkonový stupeň, při zapojení externího předzesilovače do návratu efektové smyčky. U každého bloku zesilovače jsou diskutována možná řešení a pak vybráno to nejvhodnější. Největší pozornost je pak věnována návrhu a výpočtu síťového a výstupního transformátoru a ergonomickému rozložení prvků pro dosažení co největšího odstupu S/N. Obvody zesilovače byly simulovány v programu Micro-Cap 9.0 a Tonestack 1.3. Při konstrukci byl kladen důraz na správné stínění a vedení společného zemního vodiče. Po sestavení zesilovače byla prověřena jeho stabilita, změřeny kmitočtové charakteristiky pomocí osciloskopu a zkreslení pomocí distortion meteru.This master’s thesis is dealing with low frequency all valve Stereo Amplifier unit conception for an electric guitar. The Amplifier contains two independent output stages with two power tubes EL34, working in AB class, with 40Watts of power. The apparatus is equipped with two channels, EQ correctors, parallel effects loop, output selection with lowered anode power supply, selection between silicon or tube rectifier. The preAmplifier works in mono mode and the Stereophony is reached by dividing the signal in an added effects system. This unusual solution differs from both monaural conceptions and binaural power Amplifiers which contains no preamp. It offers the possibility of Stereophony without the necessity of dividing the guitar signal before the Amplifier’s input. The sound that comes from the speaker on one side is effected and on the other side is dry by using monaural effects apparatus. The sound from both speakers is effected by using binaural effect apparatus. The Amplifier can be used as power Amplifier stage only when the return of the effect loop is used as the Amplifier input. Every available possible solution is discussed in case of each block and then the most suitable is chosen. The biggest attention is paid to a proposal and calculation of both power and output transformer, ergonomical lay-out of the stages in need of the best S/N separation. The stages were simulated in Micro-Cap 9.0 and Tonestack 1.3 computer programmes. The construction was carried out with the emphasis on proper shielding and grounding. The overall stability tests were performed after building the Amplifier as well as frequency characteristics with the scope and distortion with the distortion meter.
Jaša Jakub - One of the best experts on this subject based on the ideXlab platform.
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Integrated Stereo Amplifier for home audio listening
Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012Co-Authors: Jaša JakubAbstract:This bachelor thesis deals with design of a Stereo Amplifier, which consists of several functional blocks for the analog audio processing. This document describes the solution of individual functional audio blocks, detailed design including schematics and contains also other documents for the construction of the Amplifier. The main topic is design, simulation, construction and evaluation of a power Amplifier that uses power transistors ThermalTrak. The evaluation of the results of the whole implementation compares measured parameters with other types of Amplifiers
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Integrated Stereo Amplifier for home audio listening
Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012Co-Authors: Jaša JakubAbstract:Tento dokument pojednává o návrhu Stereofonního zesilovače, který se skládá z více funkčních audio bloků. Součástí dokumentu je řešení jednotlivých bloků, podrobného návrhu, schématu zapojení a dalších konstručních podkladů. Hlavním rozebíraným tématem je návrh, simulace schémat, konstrukce koncového zesilovače a zhodnocení použití tranzistorů ThermalTrak. Součástí je zhodnocení výsledků celé realizace a porovnání výsledků s jinými zesilovači.This bachelor thesis deals with design of a Stereo Amplifier, which consists of several functional blocks for the analog audio processing. This document describes the solution of individual functional audio blocks, detailed design including schematics and contains also other documents for the construction of the Amplifier. The main topic is design, simulation, construction and evaluation of a power Amplifier that uses power transistors ThermalTrak. The evaluation of the results of the whole implementation compares measured parameters with other types of Amplifiers.
Hideki Takegoshi - One of the best experts on this subject based on the ideXlab platform.
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Sound-evoked neurogenic responses with short latency: are they of vestibular origin?
International Congress Series, 2005Co-Authors: Toshihisa Murofushi, Shinichi Iwasaki, Yoshinari Takai, Hideki TakegoshiAbstract:Abstract Background In auditory brainstem responses (ABR), recording a large negative deflection with a latency of 3 ms (N3) could be recorded in patients with peripheral profound deafness. It is suggested that N3 might be of vestibular origin. If we can record N3 potentials in subjects with preserved hearing, recording N3 potential will be a new clinical test of the vestibular system. Methods Twelve healthy volunteers and sixteen patients with vestibular disorders were enrolled. For recording responses, surface electrodes were placed on the ipsilateral mastoid and the vertex. Recording was performed using an auditory evoked potential recording system with a minimixer and a Stereo Amplifier. Signals were amplified and band-pass-filtered (100–3000 Hz). One thousand hertz short tone bursts were presented to either ear through a headphone with or without white noise (WN) to the ipsilateral to the stimulated ear. The stimulation rate was 10 Hz. The responses to 500 stimuli were averaged. Results When 1 kHz STB (95 dBnHL, equivalent to 130 dBSPL) was presented with 100 dBSPL WN, a negative peak with 3 to 4 ms latency (N3) was observed in 23 of the 24 ears of the healthy volunteers. The presence of N3 in the patients was in agreement with the presence of the vestibular evoked myogenic potentials (VEMP), which were also recorded. Conclusion Using techniques of WN exposure to the stimulated ear, we recorded N3 in healthy subjects. On the basis of results in patients, N3 is likely to be of vestibular origin.
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Sound-evoked neurogenic responses with short latency of vestibular origin
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, 2005Co-Authors: Toshihisa Murofushi, Shinichi Iwasaki, Yoshinari Takai, Hideki TakegoshiAbstract:Abstract Objective In ABR recording, a large negative deflection with a latency of 3 ms (N3) has been recorded in patients with peripheral profound deafness. It has been suggested that N3 might be of vestibular origin. So far, N3 has been recorded only in patients with peripheral profound deafness. If we can record N3 potentials in subjects with preserved hearing, recording N3 potentials might be a new clinical test of the vestibular system. To record neurogenic potentials (N3) of vestibular origin in healthy volunteers and patients with vestibular disorders. Methods Twelve healthy volunteers (10 men and two women, aged 23–37 years) and 12 patients with vestibular disorders (6 men and 6 women, aged 29–71 years) were enrolled in this study. To record responses, surface electrodes were placed on the ipsilateral mastoid and the vertex. An electrode on the nasion served as the ground. Recording was performed using an auditory evoked potential recording system with a mini-mixer and a Stereo-Amplifier. Signals at the vertex to the ispilateral mastoid were amplified and bandpass filtered (100–3000 Hz). One thousand-hertz short tone bursts (1 kHz STB; rise/fall time=0.5 ms, plateau time=1 ms) were presented to either ear through a headphone with or without white noise (WN) ipsilateral to the stimulated ear. The stimulation rate was 10 Hz, and the analysis time was 10 ms. The responses to 500 stimuli were averaged twice. Results When 1 kHz STB (95 dBnHL, equivalent to 130 dBSPL) were presented with 100 dBSPL WN (ipsilateral to the stimulated ear), a negative peak with 3–4 ms latency (N3) was observed in 23 of the 24 ears (95.8%) with reproducibility in healthy subjects. Without WN, N3 was observed in 17 of the 24 ears (70.8%). The threshold of N3 was 90.2 dBnHL on the average. The presence of N3 in the patients was in agreement with the presence of the VEMP, which were also recorded. Conclusions Using techniques of WN exposure ipsilateral to the stimulated ear, we recorded N3 in healthy subjects and in vestibular disorder patients with preserved hearing. This negative peak is likely to be of vestibular origin. Significance N3 may be measured from subjects who cannot contract neck muscles due to their ages, mental states, or consciousness disorders. In other words, N3 may be measured from subjects from whom VEMP cannot be recorded. In combination with VEMP, N3 may be useful for the detection of lesion sites.
Bronec David - One of the best experts on this subject based on the ideXlab platform.
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Design of switching class audio power Amplifier
Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013Co-Authors: Bronec DavidAbstract:This bachelor thesis is dealing with the issues of the switched category output Amplifiers and its aim is to design and to construct a Stereo Amplifier with the energy output about 100W. The Amplifier is constructed in the switched category D. The design of the corrective preAmplifier with the correction of depths, heights and the balance functions is also described. Furthermore, this thesis deals with the description of the switched power supply with the TOPswitch control circuit. The design is also supplemented by the simulations and the printed circuits of each part. There are also some photographs of the device and the measurement protocol is included too
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Design of switching class audio power Amplifier
Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013Co-Authors: Bronec DavidAbstract:Obsahem této bakalářské práce je prostudovat problematiku výkonových zesilovačů spínané třídy a na základě získaných informací navrhnou a sestavit Stereo zesilovač o výkonu cca 100W. Zesilovač je konstruován ve spínané třídě D. Je zde popsán i návrh korekčního předzesilovače s korekcí hloubek, výšek a funkcí balanc. Dále v práci najdeme popis konstrukce spínaného zdroje s řídícím obvodem TOPSwitch. Návrh je doplněn simulacemi a plošnými spoji jednotlivých částí. Jsou zde uvedeny i fotografie vyrobeného zařízení se záznamem o měření.This bachelor thesis is dealing with the issues of the switched category output Amplifiers and its aim is to design and to construct a Stereo Amplifier with the energy output about 100W. The Amplifier is constructed in the switched category D. The design of the corrective preAmplifier with the correction of depths, heights and the balance functions is also described. Furthermore, this thesis deals with the description of the switched power supply with the TOPswitch control circuit. The design is also supplemented by the simulations and the printed circuits of each part. There are also some photographs of the device and the measurement protocol is included too.